| **LOANS AND ALLOWANCE FOR CREDIT LOSSES (Consumer Lending Asset Quality Indicators - FICO and CLTV Range) (Details) - Consumer - USD ($) $ in Thousands** | Jun. 30, 2016 | Dec. 31, 2015 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| Residential mortgages                                                                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | $ 6,572,498   | $ 6,467,755   |
| Home Equity Loans and Lines of Credit                                                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 6,078,463     | 6,151,232     |
| LTV not applicable | Residential mortgages                                                                                                                |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 574,665       | 462,640       |
| LTV not applicable | Home Equity Loans and Lines of Credit                                                                                                |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 263,905       | 286,419       |
| LTV less than or equal to 70% | Residential mortgages                                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 4,047,911     | 3,842,373     |
| LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 3,366,229     | 3,241,188     |
| LTV of 70.01% to 80% | Residential mortgages                                                                                                              |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 1,330,860     | 1,440,194     |
| LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                                                              |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 1,992,187     | 2,088,030     |
| LTV of 80.01% to 90% | Residential mortgages                                                                                                              |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 319,570       | 336,893       |
| LTV of 90.01% to 100% | Residential mortgages                                                                                                             |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 183,780       | 227,494       |
| LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                                                             |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 282,724       | 332,064       |
| LTV of 100.01% to 110% | Residential mortgages                                                                                                            |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 48,475        | 64,578        |
| LTV greater than 110% | Residential mortgages                                                                                                             |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 67,237        | 93,583        |
| LTV greater than 110% | Home Equity Loans and Lines of Credit                                                                                             |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 173,418       | 203,531       |
| FICO score not applicable | Residential mortgages                                                                                                         |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 603,313       | 476,858       |
| FICO score not applicable | Home Equity Loans and Lines of Credit                                                                                         |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 190,166       | 193,074       |
| FICO score not applicable | LTV not applicable | Residential mortgages                                                                                    |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 573,780       | 461,839       |
| FICO score not applicable | LTV not applicable | Home Equity Loans and Lines of Credit                                                                    |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 186,139       | 192,379       |
| FICO score not applicable | LTV less than or equal to 70% | Residential mortgages                                                                         |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 28,688        | 12,250        |
| FICO score not applicable | LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                                         |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 2,217         | 390           |
| FICO score not applicable | LTV of 70.01% to 80% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 845           | 2,769         |
| FICO score not applicable | LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 1,810         | 305           |
| FICO score not applicable | LTV of 80.01% to 90% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 0             | 0             |
| FICO score not applicable | LTV of 90.01% to 100% | Residential mortgages                                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 0             | 0             |
| FICO score not applicable | LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 0             | 0             |
| FICO score not applicable | LTV of 100.01% to 110% | Residential mortgages                                                                                |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 0             | 0             |
| FICO score not applicable | LTV greater than 110% | Residential mortgages                                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 0             | 0             |
| FICO score not applicable | LTV greater than 110% | Home Equity Loans and Lines of Credit                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 0             | 0             |
| FICO score less than 600 | Residential mortgages                                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 336,710       | 362,824       |
| FICO score less than 600 | Home Equity Loans and Lines of Credit                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 269,914       | 290,439       |
| FICO score less than 600 | LTV not applicable | Residential mortgages                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 119           | 128           |
| FICO score less than 600 | LTV not applicable | Home Equity Loans and Lines of Credit                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 10,831        | 11,110        |
| FICO score less than 600 | LTV less than or equal to 70% | Residential mortgages                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 224,445       | 226,185       |
| FICO score less than 600 | LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 154,748       | 155,306       |
| FICO score less than 600 | LTV of 70.01% to 80% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 55,551        | 69,698        |
| FICO score less than 600 | LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 67,073        | 79,389        |
| FICO score less than 600 | LTV of 80.01% to 90% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 25,527        | 30,491        |
| FICO score less than 600 | LTV of 90.01% to 100% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 15,296        | 18,279        |
| FICO score less than 600 | LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 19,757        | 22,373        |
| FICO score less than 600 | LTV of 100.01% to 110% | Residential mortgages                                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 7,614         | 8,441         |
| FICO score less than 600 | LTV greater than 110% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 8,158         | 9,602         |
| FICO score less than 600 | LTV greater than 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 17,505        | 22,261        |
| FICO score of 600 to 639 | Residential mortgages                                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 231,683       | 252,976       |
| FICO score of 600 to 639 | Home Equity Loans and Lines of Credit                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 255,467       | 265,987       |
| FICO score of 600 to 639 | LTV not applicable | Residential mortgages                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 53            | 1             |
| FICO score of 600 to 639 | LTV not applicable | Home Equity Loans and Lines of Credit                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 8,426         | 8,871         |
| FICO score of 600 to 639 | LTV less than or equal to 70% | Residential mortgages                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 153,871       | 158,290       |
| FICO score of 600 to 639 | LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 143,840       | 140,277       |
| FICO score of 600 to 639 | LTV of 70.01% to 80% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 38,696        | 43,002        |
| FICO score of 600 to 639 | LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 75,934        | 83,548        |
| FICO score of 600 to 639 | LTV of 80.01% to 90% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 21,344        | 23,281        |
| FICO score of 600 to 639 | LTV of 90.01% to 100% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 8,341         | 15,585        |
| FICO score of 600 to 639 | LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 16,056        | 20,766        |
| FICO score of 600 to 639 | LTV of 100.01% to 110% | Residential mortgages                                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 4,271         | 5,238         |
| FICO score of 600 to 639 | LTV greater than 110% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 5,107         | 7,579         |
| FICO score of 600 to 639 | LTV greater than 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 11,211        | 12,525        |
| FICO Score of 640 to 679 | Residential mortgages                                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 439,896       | 419,770       |
| FICO Score of 640 to 679 | Home Equity Loans and Lines of Credit                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 497,602       | 500,728       |
| FICO Score of 640 to 679 | LTV not applicable | Residential mortgages                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 64            | 230           |
| FICO Score of 640 to 679 | LTV not applicable | Home Equity Loans and Lines of Credit                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 10,988        | 12,534        |
| FICO Score of 640 to 679 | LTV less than or equal to 70% | Residential mortgages                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 268,152       | 252,727       |
| FICO Score of 640 to 679 | LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 270,010       | 254,481       |
| FICO Score of 640 to 679 | LTV of 70.01% to 80% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 83,716        | 81,552        |
| FICO Score of 640 to 679 | LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 163,122       | 174,223       |
| FICO Score of 640 to 679 | LTV of 80.01% to 90% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 39,648        | 35,001        |
| FICO Score of 640 to 679 | LTV of 90.01% to 100% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 33,110        | 29,125        |
| FICO Score of 640 to 679 | LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 32,871        | 32,925        |
| FICO Score of 640 to 679 | LTV of 100.01% to 110% | Residential mortgages                                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 7,054         | 9,101         |
| FICO Score of 640 to 679 | LTV greater than 110% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 8,152         | 12,034        |
| FICO Score of 640 to 679 | LTV greater than 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 20,611        | 26,565        |
| FICO Score of 680 to 719 | Residential mortgages                                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 761,864       | 792,060       |
| FICO Score of 680 to 719 | Home Equity Loans and Lines of Credit                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 846,702       | 851,662       |
| FICO Score of 680 to 719 | LTV not applicable | Residential mortgages                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 79            | 19            |
| FICO Score of 680 to 719 | LTV not applicable | Home Equity Loans and Lines of Credit                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 11,301        | 14,273        |
| FICO Score of 680 to 719 | LTV less than or equal to 70% | Residential mortgages                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 487,517       | 462,180       |
| FICO Score of 680 to 719 | LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 456,666       | 431,818       |
| FICO Score of 680 to 719 | LTV of 70.01% to 80% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 150,971       | 183,568       |
| FICO Score of 680 to 719 | LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 300,494       | 317,260       |
| FICO Score of 680 to 719 | LTV of 80.01% to 90% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 62,688        | 62,670        |
| FICO Score of 680 to 719 | LTV of 90.01% to 100% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 39,056        | 51,659        |
| FICO Score of 680 to 719 | LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 51,404        | 56,589        |
| FICO Score of 680 to 719 | LTV of 100.01% to 110% | Residential mortgages                                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 6,924         | 9,194         |
| FICO Score of 680 to 719 | LTV greater than 110% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 14,629        | 22,770        |
| FICO Score of 680 to 719 | LTV greater than 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 26,837        | 31,722        |
| FICO Score of 720 to 759 | Residential mortgages                                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 1,184,154     | 1,183,942     |
| FICO Score of 720 to 759 | Home Equity Loans and Lines of Credit                                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 1,154,015     | 1,156,986     |
| FICO Score of 720 to 759 | LTV not applicable | Residential mortgages                                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 106           | 339           |
| FICO Score of 720 to 759 | LTV not applicable | Home Equity Loans and Lines of Credit                                                                     |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 10,028        | 12,673        |
| FICO Score of 720 to 759 | LTV less than or equal to 70% | Residential mortgages                                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 727,348       | 681,473       |
| FICO Score of 720 to 759 | LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                                          |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 649,337       | 614,748       |
| FICO Score of 720 to 759 | LTV of 70.01% to 80% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 324,614       | 341,934       |
| FICO Score of 720 to 759 | LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 406,400       | 425,744       |
| FICO Score of 720 to 759 | LTV of 80.01% to 90% | Residential mortgages                                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 64,785        | 72,729        |
| FICO Score of 720 to 759 | LTV of 90.01% to 100% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 43,882        | 55,461        |
| FICO Score of 720 to 759 | LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 52,877        | 63,840        |
| FICO Score of 720 to 759 | LTV of 100.01% to 110% | Residential mortgages                                                                                 |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 9,229         | 11,024        |
| FICO Score of 720 to 759 | LTV greater than 110% | Residential mortgages                                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 14,190        | 20,982        |
| FICO Score of 720 to 759 | LTV greater than 110% | Home Equity Loans and Lines of Credit                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 35,373        | 39,981        |
| FICO Score Equal to or Greater than 760 | Residential mortgages                                                                                           |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 3,014,878     | 2,979,325     |
| FICO Score Equal to or Greater than 760 | Home Equity Loans and Lines of Credit                                                                           |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 2,864,597     | 2,892,356     |
| FICO Score Equal to or Greater than 760 | LTV not applicable | Residential mortgages                                                                      |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 464           | 84            |
| FICO Score Equal to or Greater than 760 | LTV not applicable | Home Equity Loans and Lines of Credit                                                      |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 26,192        | 34,579        |
| FICO Score Equal to or Greater than 760 | LTV less than or equal to 70% | Residential mortgages                                                           |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 2,157,890     | 2,049,268     |
| FICO Score Equal to or Greater than 760 | LTV less than or equal to 70% | Home Equity Loans and Lines of Credit                                           |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 1,689,411     | 1,644,168     |
| FICO Score Equal to or Greater than 760 | LTV of 70.01% to 80% | Residential mortgages                                                                    |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 676,467       | 717,671       |
| FICO Score Equal to or Greater than 760 | LTV of 70.01% to 90% | Home Equity Loans and Lines of Credit                                                    |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 977,354       | 1,007,561     |
| FICO Score Equal to or Greater than 760 | LTV of 80.01% to 90% | Residential mortgages                                                                    |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 105,578       | 112,721       |
| FICO Score Equal to or Greater than 760 | LTV of 90.01% to 100% | Residential mortgages                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 44,095        | 57,385        |
| FICO Score Equal to or Greater than 760 | LTV of 90.01% to 110% | Home Equity Loans and Lines of Credit                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 109,759       | 135,571       |
| FICO Score Equal to or Greater than 760 | LTV of 100.01% to 110% | Residential mortgages                                                                  |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 13,383        | 21,580        |
| FICO Score Equal to or Greater than 760 | LTV greater than 110% | Residential mortgages                                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | 17,001        | 20,616        |
| FICO Score Equal to or Greater than 760 | LTV greater than 110% | Home Equity Loans and Lines of Credit                                                   |          |          |
| **Loans Receivable [Line Items]**                                                                                                                         |          |          |
| Financing receivables                                                                                                                                     | $ 61,881      | $ 70,477      |

| X                                                                                                                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The balance of financing receivables including loans held-for-sale, before allowance for credit losses.
+ References
No definition available.
+ Details**Name:**sov_FinancingReceivableIncludingReceivableHeldForSaleGross**Namespace Prefix:**sov_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
+ Details**Name:**us-gaap_AccountsNotesAndLoansReceivableLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialMortgageMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=sov_HomeEquityLoansandLinesofCreditMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LtvNotApplicableMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LTVlessthanorequalto70Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LTVof70.01to80Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LTVof70.01to90Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LtvOf8001To90Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LtvOf9001To100Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LTVof90.01to110Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                          |
|--------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LTVof100.01to110Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_LoanToValueAxis=sov_LTVgreaterthan110Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CreditScoreFicoAxis=sov_FicoScoreNotRefreshedMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CreditScoreFicoAxis=sov_FICOScoreLessthan600Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CreditScoreFicoAxis=sov_FICOScoreof640to679Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CreditScoreFicoAxis=sov_FICOScoreof680to719Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CreditScoreFicoAxis=sov_FICOScoreof720to759Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_CreditScoreFicoAxis=sov_FICOScoreEqualtoorGreaterthan760Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |