| **BORROWINGS (Tables)**                          | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| **Debt Instrument [Line Items]**                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| Schedule of Maturities of Long-term Debt         | The following table sets forth the maturities of the Company’s consolidated borrowings and debt obligations at December 31, 2015:  (in thousands)2016$13,998,34720179,308,02420188,013,39120196,270,71820205,403,368Thereafter6,092,255Total$49,086,103                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        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| SHUSA                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| **Debt Instrument [Line Items]**                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| Schedule of Borrowings and Other Debt Obligation | The following table presents information regarding the parent holding company ("Holding Company") borrowings and other debt obligations at the dates indicated: December 31, 2015 December 31, 2014 Balance EffectiveRate Balance EffectiveRate (dollars in thousands)3.00% senior notes, due September 2015$— —% $598,788 3.28%4.625% senior notes, due April 2016 475,723 4.85% 474,718 4.85%3.45% senior notes, due August 2018497,800 3.62% 497,025 3.62%2.65% senior notes, due April 2020993,151 2.82% — —%4.50% senior notes, due July 20251,094,483 4.56% — —%Junior subordinated debentures - Capital Trust VI, due June 203669,775 7.91% 69,751 7.91%Common securities - Capital Trust VI10,000 7.91% 10,000 7.91%Junior subordinated debentures - Capital Trust IX, due July 2036149,404 2.18% 149,375 2.04%Common securities - Capital Trust IX4,640 2.18% 4,640 2.04%     Total holding company borrowings and other debt obligations$3,294,976 3.91% $1,804,297 3.89% 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| Santander Bank                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| **Debt Instrument [Line Items]**                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| Schedule of Borrowings and Other Debt Obligation | The following table presents information regarding the Bank's borrowings and other debt obligations at the dates indicated:  December 31, 2015 December 31, 2014 Balance EffectiveRate Balance EffectiveRate (dollars in thousands)2.00% senior notes, due January 2018$746,381 2.24% $— —%Senior notes, due January 2018(1)249,415 1.31% — —%8.750% subordinated debentures, due May 2018498,175 8.92% 497,530 8.92%FHLB advances, maturing through July 201913,885,000 1.40% 9,455,000 2.06%Subordinated term loan, due February 2019130,899 6.15% 139,180 6.00%REIT (2) preferred, due May 2020154,930 13.66% 153,417 13.64%Subordinated term loan, due August 202230,344 7.89% 31,428 7.77%     Total Bank borrowings and other debt obligations$15,695,144 1.85% $10,276,555 2.64%(1)  These notes will bear interest at a rate equal to three-month London Interbank Offered Rate ("LIBOR") plus 93 basis points per annum.(2)  Real estate investment trust ("REIT")                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    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| SC                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| **Debt Instrument [Line Items]**                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| Schedule of Borrowings and Other Debt Obligation | FacilitiesThe following tables present information regarding SC's credit facilities as of December 31, 2015 and December 31, 2014: December 31, 2015 Balance EffectiveRate Assets Pledged Restricted Cash Pledged (dollars in thousands)Warehouse line, maturing on various dates(1)$808,135 1.29% $1,137,257 $24,942Warehouse line, due June 2016378,301 1.48% 535,737 —Warehouse line, due November 2016(2)175,000 1.90% — —Warehouse line, due November 2016(2)250,000 1.90% — 2,501Warehouse line, due July 2017(3)682,720 1.35% 809,185 20,852Warehouse line, due July 2017(4)2,247,443 1.41% 3,412,321 48,589Warehouse line, due September 2017565,399 1.20% 824,327 15,759Warehouse line, due December 2017(5)944,877 1.56% 1,345,051 32,038Repurchase facility, due December 2016(6)850,904 2.07% — 34,166Line of credit with related party, due December 2016(7)500,000 2.65% — —Line of credit with related party, due December 2016(7)1,000,000 2.61% — —Line of credit with related party, due December 2018(7)800,000 2.84% — —     Total SC revolving credit facilities$9,202,779 1.81% $8,063,878 $178,847(1)  As of December 31, 2015, half of the outstanding balance on this facility matured in March 2016 and half matured in March 2017. On March 29, 2016, the facility was amended to, among other changes, extend the maturity for half of the balance to March 2017 and half to March 2018.(2)  These lines are collateralized by residuals retained by SC(3)  This line is held exclusively for financing Chrysler loans.(4)  This line is held exclusively for financing Chrysler leases.(5)  In December 2015, the commitment on this warehouse was amended to extend the commitment termination date to December 2017.(6)  This repurchase facility is collateralized by securitization notes payable retained by SC. No portion of this facility is unsecured. This facility has rolling 30-day and 90 -day maturities.(7)  These lines are also collateralized by securitization notes payable and residuals retained by SC. As of December 31, 2015, $1.4 billion of the aggregate outstanding balances on these credit facilities was unsecured.NOTE 12. BORROWINGS (continued) December 31, 2014 Balance EffectiveRate Assets Pledged Restricted Cash Pledged (dollars in thousands)Warehouse line, maturing on various dates(1)$397,452 1.26% $589,529 $20,661Warehouse line, due March 2015(2)250,594 0.98% — —Warehouse line, due June 2015243,736 1.17% 344,822 —Warehouse line, due September 2015(3)199,980 1.96% 351,755 13,169Warehouse line, due December 2015468,565 0.93% 641,709 16,467Warehouse line, due June 2016(4)2,201,511 0.98% 3,249,263 65,414Warehouse line, due June 20161,051,777 1.06% 1,481,135 28,316Warehouse line, due October 2016(3)240,487 2.02% 299,195 17,143Warehouse line, due November 2016(5)175,000 1.71% — —Warehouse line, due November 2016(5)250,000 1.71% — 2,500Repurchase facility, maturing on various dates(6)923,225 1.63% — 34,184Line of credit with related party, due December 2016(7)500,000 2.46% 1,340 —Line of credit with related party, due December 2016(7)1,750,000 2.33% — —Line of credit with related party, due December 2018(7)1,140,000 2.85% 9,701 —     Total SC revolving credit facilities$9,792,327 1.68% $6,968,449 $197,854(1)  Half of the outstanding balance on this facility had maturity dates in March 2015 and half matures in March 2016.(2)  This line is collateralized by securitization notes payable retained by SC.(3)  These lines are held exclusively for personal consumer term loans.(4)  This line is held exclusively for Chrysler Capital retail loan and lease financing.(5)  These lines are collateralized by residuals retained by SC.(6)  This repurchase facility is collateralized by securitization notes payable retained by SC. No portion of this facility is unsecured. This facility has rolling 30-day and 90-day maturities.(7)  These lines are also collateralized by securitization notes payable and residuals retained by SC. As of December 31, 2014, $2.2 billion of the aggregate outstanding balances on these credit facilities wasFinancingsThe following tables present information regarding SC's secured structured financings as of December 31, 2015 and December 31, 2014: December 31, 2015 Balance Initial Note Amounts Issued Initial Weighted Average Interest Rate Range Collateral Restricted Cash (dollars in thousands)SC public securitizations, maturing on various dates(1)$12,679,987 $24,923,292 0.89% - 2.29% $16,256,067 $1,242,857SC privately issued amortizing notes, maturing on various dates(1)8,213,217 11,729,171 0.88% - 2.81% 11,495,352 457,840     Total SC secured structured financings$20,893,204 $36,652,463 0.88% - 2.81% $27,751,419 $1,700,697NOTE 12. BORROWINGS (continued) December 31, 2014 Balance Initial Note Amounts Issued Initial Weighted Average Interest Rate Range Collateral Restricted Cash (dollars in thousands)SC public securitizations, maturing on various dates(1)$11,523,729 $26,682,930 0.89% - 2.80% $14,345,242 $1,184,047SC privately issued amortizing notes, maturing on various dates(1)6,282,474 8,499,111 1.05% - 1.85% 9,114,997 281,038     Total SC secured structured financings$17,806,203 $35,182,041 0.89% - 2.80% $23,460,239 $1,465,085(1)  SC has entered into various securitization transactions involving its retail automotive installment loans and leases. These transactions are accounted for as secured financings and therefore both the securitized RIC and the related securitization debt issued by SPEs, remain on the Consolidated Balance Sheet. The maturity of this debt is based on the timing of repayments from the securit |

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| - 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.
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| - Definition
Tabular disclosure of information pertaining to short-term and long-debt instruments or arrangements, including but not limited to identification of terms, features, collateral requirements and other information necessary to a fair presentation.
+ References
No definition available.
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| - Definition
Tabular disclosure of the combined aggregate amount of maturities and sinking fund requirements for all long-term borrowings for each of the five years following the date of the latest balance sheet date presented.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601
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