| **FAIR VALUE (Fair Value Measurements, Recurring) (Details) (USD $)**                                                                                   | Mar. 31, 2015                                                                                                                                                                                                                                                                                                            | Dec. 31, 2014                                                                                                                                                                                                                                                                                                            |
|---------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | $ 18,429,023,000us-gaap_AvailableForSaleSecurities                                                                                                                                                                                                                                                                       | $ 15,908,078,000us-gaap_AvailableForSaleSecurities                                                                                                                                                                                                                                                                       |
| Trading securities                                                                                                                                      | 0us-gaap_TradingSecurities                                                                                                                                                                                                                                                                                               | 833,936,000us-gaap_TradingSecurities                                                                                                                                                                                                                                                                                     |
| Retail installment contracts held for investment                                                                                                        | 676,100,000us-gaap_LoansReceivableFairValueDisclosure                                                                                                                                                                                                                                                                    | 845,900,000us-gaap_LoansReceivableFairValueDisclosure                                                                                                                                                                                                                                                                    |
| Mortgage servicing rights                                                                                                                               | 135,452,000us-gaap_ServicingAssetAtFairValueAmount                                                                                                                                                                                                                                                                       | 145,047,000us-gaap_ServicingAssetAtFairValueAmount                                                                                                                                                                                                                                                                       |
| Derivative assets at fair value                                                                                                                         | 451,267,000us-gaap_DerivativeAssets                                                                                                                                                                                                                                                                                      | 366,061,000us-gaap_DerivativeAssets                                                                                                                                                                                                                                                                                      |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 338,481,000us-gaap_DerivativeLiabilities                                                                                                                                                                                                                                                                                 | 353,882,000us-gaap_DerivativeLiabilities                                                                                                                                                                                                                                                                                 |
| US Treasury and government agency securities [Member]                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,154,164,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember                                                                                                                                                                                  | 1,695,767,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember                                                                                                                                                                                  |
| Corporate debt [Member]                                                                                                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,139,039,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember                                                                                                                                                                                  | 2,182,401,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember                                                                                                                                                                                  |
| Asset-backed securities [Member]                                                                                                                        |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,997,885,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember                                                                                                                                                                                    | 2,720,403,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember                                                                                                                                                                                    |
| Equity securities [Member]                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 10,475,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                                                                                                                                                                                            | 10,343,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                                                                                                                                                                                            |
| State and municipal securities [Member]                                                                                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 1,442,353,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                                                                                                                                                                                           | 1,823,462,000us-gaap_AvailableForSaleSecurities/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                                                                                                                                                                                           |
| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]                                                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 10,475,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                        | 10,343,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                        |
| Trading securities                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     | 0us-gaap_TradingSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                                          |
| Loans held-for-sale                                                                                                                                     | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                        | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                        |
| Mortgage servicing rights                                                                                                                               | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                            | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                            |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                                           | 0us-gaap_DerivativeAssets/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                                           |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                                      | 0us-gaap_DerivativeLiabilities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member                                                                                                                                                                                                      |
| Significant Other Observable Inputs (Level 2) [Member]                                                                                                  |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 16,904,031,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                    | 14,630,092,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                    |
| Trading securities                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     | 833,936,000us-gaap_TradingSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                                |
| Loans held-for-sale                                                                                                                                     | 1,418,646,000us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                            | 260,251,000us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                              |
| Mortgage servicing rights                                                                                                                               | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                            | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                            |
| Derivative assets at fair value                                                                                                                         | 456,644,000us-gaap_DerivativeAssets/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                                 | 384,100,000us-gaap_DerivativeAssets/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                                 |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 478,553,000us-gaap_DerivativeLiabilities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                            | 374,636,000us-gaap_DerivativeLiabilities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member                                                                                                                                                                                            |
| Significant Unobservable Inputs (Level 3) [Member]                                                                                                      |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 1,514,517,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                     | 1,267,643,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                     |
| Trading securities                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     | 0us-gaap_TradingSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                                          |
| Loans held-for-sale                                                                                                                                     | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                        | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                        |
| Mortgage servicing rights                                                                                                                               | 135,452,000us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                  | 145,047,000us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                  |
| Derivative assets at fair value                                                                                                                         | 7,022,000us-gaap_DerivativeAssets/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                                   | 3,070,000us-gaap_DerivativeAssets/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                                   |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 385,000us-gaap_DerivativeLiabilities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                                | 355,000us-gaap_DerivativeLiabilities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member                                                                                                                                                                                                |
| Recurring [Member]                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 18,429,023,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                              | 15,908,078,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                              |
| Trading securities                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     | 833,936,000us-gaap_TradingSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                                          |
| Retail installment contracts held for investment                                                                                                        | 676,097,000us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                         | 845,911,000us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                         |
| Loans held-for-sale                                                                                                                                     | 316,026,000us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                        | 213,666,000us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                        |
| Mortgage servicing rights                                                                                                                               | 135,452,000us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                            | 145,047,000us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                            |
| Total financial assets                                                                                                                                  | 20,020,264,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                               | 18,333,808,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                               |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Total financial liabilities                                                                                                                             | 478,938,000us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                             | 374,991,000us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                                                                             |
| Recurring [Member] | Mortgage banking interest rate lock commitments [Member]                                                                           |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 6,999,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                            | 3,063,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                            |
| Recurring [Member] | Mortgage banking forward sell commitments [Member]                                                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 2,611,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                         | 2,424,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                         |
| Recurring [Member] | Customer related [Member]                                                                                                          |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 377,309,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               | 289,240,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 340,666,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                          | 252,955,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                          |
| Recurring [Member] | Total return swap [Member]                                                                                                         |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 1,704,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                   | 2,018,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                   |
| Recurring [Member] | Foreign exchange [Member]                                                                                                          |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 31,997,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               | 20,033,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 30,228,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                          | 17,390,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                          |
| Recurring [Member] | Mortgage servicing [Member]                                                                                                        |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 2,237,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                    | 7,432,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                    |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 3,473,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               | 7,448,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               |
| Recurring [Member] | Interest rate cap agreements [Member]                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 31,585,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                       | 49,762,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                       |
| Recurring [Member] | Interest rate swap agreements [Member]                                                                                             |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         |                                                                                                                                                                                                                                                                                                                     | 535,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                         |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 14,767,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                 | 12,743,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                 |
| Recurring [Member] | Option for interest rate cap [Member]                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 31,614,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                             | 49,806,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                             |
| Recurring [Member] | Other [Member]                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 8,804,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                          | 6,543,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                          |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 11,267,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                    | 7,896,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                                     |
| Recurring [Member] | Fair value [Member]                                                                                                                |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 4,624,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             | 2,943,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 4,239,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                        | 1,759,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                        |
| Recurring [Member] | Cash flow [Member]                                                                                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 111,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                | 7,619,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                              |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 38,369,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                        | 20,552,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                        |
| Recurring [Member] | US Treasury and government agency securities [Member]                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,154,164,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember                                                                                       | 1,695,767,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember                                                                                       |
| Recurring [Member] | Corporate debt [Member]                                                                                                            |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,139,039,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember                                                                                       | 2,182,401,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember                                                                                       |
| Recurring [Member] | Asset-backed securities [Member]                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,997,885,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember                                                                                         | 2,720,403,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember                                                                                         |
| Recurring [Member] | Equity securities [Member]                                                                                                         |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 10,475,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                                                                                                 | 10,343,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                                                                                                 |
| Recurring [Member] | State and municipal securities [Member]                                                                                            |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 1,442,353,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                                                                                                | 1,823,462,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                                                                                                |
| Recurring [Member] | Mortgage backed securities [Member]                                                                                                |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 9,685,107,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember                                                                                      | 7,475,702,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember                                                                                      |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]                                                            |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 10,475,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             | 10,343,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             |
| Trading securities                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     | 0us-gaap_TradingSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               |
| Retail installment contracts held for investment                                                                                                        | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                              | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                              |
| Loans held-for-sale                                                                                                                                     | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             |
| Mortgage servicing rights                                                                                                                               | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                 | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                 |
| Total financial assets                                                                                                                                  | 10,475,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                              | 10,343,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                              |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Total financial liabilities                                                                                                                             | 0us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                  | 0us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                  |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage banking interest rate lock commitments [Member] |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage banking forward sell commitments [Member]       |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                            | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                            |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Customer related [Member]                                |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                    | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                    |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Total return swap [Member]                               |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                      | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                      |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign exchange [Member]                                |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                   | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                   |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                              | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                              |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage servicing [Member]                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                       | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                       |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                  | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                  |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest rate cap agreements [Member]                    |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                           | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                           |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest rate swap agreements [Member]                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         |                                                                                                                                                                                                                                                                                                                     | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                          |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                     | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                     |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Option for interest rate cap [Member]                    |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                 | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                 |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other [Member]                                           |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                             | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                             |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                        | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                        |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair value [Member]                                      |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember           | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember           |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash flow [Member]                                       |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                 | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                 |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember            | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember            |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | US Treasury and government agency securities [Member]    |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember              | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember              |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate debt [Member]                                  |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember              | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember              |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Asset-backed securities [Member]                         |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember                |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity securities [Member]                               |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 10,475,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember            | 10,343,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember            |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | State and municipal securities [Member]                  |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                       | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                       |
| Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage backed securities [Member]                      |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember             | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel1Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember             |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]                                                                             |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 16,904,031,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                         | 14,630,092,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                         |
| Trading securities                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     | 833,936,000us-gaap_TradingSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                     |
| Retail installment contracts held for investment                                                                                                        | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                              | 0us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                              |
| Loans held-for-sale                                                                                                                                     | 316,026,000us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                   | 213,666,000us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                   |
| Mortgage servicing rights                                                                                                                               | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                 | 0us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                 |
| Total financial assets                                                                                                                                  | 17,676,701,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                          | 16,061,794,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                          |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Total financial liabilities                                                                                                                             | 478,553,000us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                        | 374,636,000us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                        |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage banking interest rate lock commitments [Member]                  |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage banking forward sell commitments [Member]                        |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 2,611,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                    | 2,424,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                    |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Customer related [Member]                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 377,309,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                          | 289,240,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                          |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 340,666,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                     | 252,955,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                     |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Total return swap [Member]                                                |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 1,422,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                              | 1,736,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                              |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign exchange [Member]                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 31,997,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                          | 20,033,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                          |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 30,228,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                     | 17,390,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                     |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage servicing [Member]                                               |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 2,237,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               | 7,432,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 3,473,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                          | 7,448,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                          |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest rate cap agreements [Member]                                     |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 31,585,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                  | 49,762,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                  |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest rate swap agreements [Member]                                    |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         |                                                                                                                                                                                                                                                                                                                     | 535,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                    |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 14,767,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                            | 12,743,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                            |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Option for interest rate cap [Member]                                     |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 31,614,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                        | 49,806,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                        |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other [Member]                                                            |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 8,781,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                     | 6,536,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 11,164,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               | 7,823,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value [Member]                                                       |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 4,624,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember        | 2,943,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember        |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 4,239,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember   | 1,759,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember   |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Cash flow [Member]                                                        |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 111,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember           | 7,619,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember         |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 38,369,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember   | 20,552,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember   |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | US Treasury and government agency securities [Member]                     |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,154,164,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember  | 1,695,767,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember  |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Corporate debt [Member]                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 2,139,039,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember  | 2,182,401,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember  |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Asset-backed securities [Member]                                          |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 1,483,368,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember    | 1,452,760,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember    |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Equity securities [Member]                                                |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                     | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                     |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | State and municipal securities [Member]                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 1,442,353,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember           | 1,823,462,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember           |
| Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage backed securities [Member]                                       |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 9,685,107,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember | 7,475,702,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel2Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]                                                                                 |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 1,514,517,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                          | 1,267,643,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                          |
| Trading securities                                                                                                                                      |                                                                                                                                                                                                                                                                                                                     | 0us-gaap_TradingSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                                               |
| Retail installment contracts held for investment                                                                                                        | 676,097,000us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                    | 845,911,000us-gaap_LoansReceivableFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                    |
| Loans held-for-sale                                                                                                                                     | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             | 0us-gaap_LoansHeldForSaleFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                             |
| Mortgage servicing rights                                                                                                                               | 135,452,000us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                       | 145,047,000us-gaap_ServicingAssetAtFairValueAmount/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                       |
| Total financial assets                                                                                                                                  | 2,333,088,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                           | 2,261,671,000us-gaap_AssetsFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                           |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Total financial liabilities                                                                                                                             | 385,000us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                            | 355,000us-gaap_LiabilitiesFairValueDisclosure/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                                                                            |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage banking interest rate lock commitments [Member]                      |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 6,999,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                       | 3,063,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateLockCommitmentsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                       |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage banking forward sell commitments [Member]                            |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                            | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_ForwardCommitmentsToSellLoansMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                            |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Customer related [Member]                                                     |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                    | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                    |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_CustomerRelatedDerivativesMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                               |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Total return swap [Member]                                                    |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 282,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                | 282,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_TotalReturnSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Foreign exchange [Member]                                                     |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                   | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                   |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                              | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_ForeignExchangeContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                              |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage servicing [Member]                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                       | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                       |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                  | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_MortgageServicingRightsMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                  |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest rate cap agreements [Member]                                         |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                           | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                           |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Interest rate swap agreements [Member]                                        |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         |                                                                                                                                                                                                                                                                                                                     | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                          |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                     | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_InterestRateSwapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                     |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Option for interest rate cap [Member]                                         |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                 | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= sov_OptionforInterestRateCapMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                 |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other [Member]                                                                |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 23,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                        | 7,000us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                         |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 103,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                  | 73,000us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentRiskAxis= us-gaap_OtherContractMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                                   |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value [Member]                                                           |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember           | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_FairValueHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember           |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Cash flow [Member]                                                            |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivative assets at fair value                                                                                                                         | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                 | 0us-gaap_DerivativeAssets/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember                 |
| **Financial liabilities:**                                                                                                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Derivatives                                                                                                                                             | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember            | 0us-gaap_DerivativeLiabilities/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis= us-gaap_CashFlowHedgingMember/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember            |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | US Treasury and government agency securities [Member]                         |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember              | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_USTreasuryAndGovernmentMember              |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Corporate debt [Member]                                                       |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember              | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_CorporateDebtSecuritiesMember              |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Asset-backed securities [Member]                                              |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 1,514,517,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember    | 1,267,643,000us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_AssetBackedSecuritiesMember    |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Equity securities [Member]                                                    |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                     | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_EquitySecuritiesMember                     |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | State and municipal securities [Member]                                       |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                       | 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MunicipalBondsMember                       |
| Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage backed securities [Member]                                           |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| **Financial assets:**                                                                                                                                   |                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale investment securities                                                                                                                | $ 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember           | $ 0us-gaap_AvailableForSaleSecurities/ us-gaap_FairValueByFairValueHierarchyLevelAxis= us-gaap_FairValueInputsLevel3Member/ us-gaap_FairValueByMeasurementFrequencyAxis= us-gaap_FairValueMeasurementsRecurringMember/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis= us-gaap_MortgageBackedSecuritiesMember           |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value of financial and nonfinancial obligations.
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| X                                                                                                                                                                                                                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878
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