| **OTHER ASSETS**                                                                 | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| **Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| OTHER ASSETS                                                                     | OTHER ASSETSThe following is a detail of items that comprise other assets at March 31, 2016 and December 31, 2015:  March 31, 2016 December 31, 2015  (in thousands)Income tax receivables $600,936 $607,817Derivative assets at fair value 481,733 355,169Other repossessed assets 190,565 204,494MSRs, at fair value 130,742 147,233Prepaid expenses 176,733 162,879OREO 36,981 38,959Miscellaneous assets and receivables 551,309 290,055Total other assets $2,168,999 $1,806,606Refer to Note 12 to the Condensed Consolidated Financial Statements for further details about income tax receivables and Note 11 to the Condensed Consolidated Financial Statements for further details about derivative assets. Other repossessed assets primarily consist of SC's vehicle inventory, which is obtained through repossession. OREO consists primarily of the Bank's foreclosed properties. Miscellaneous assets and receivables includes, but is not limited to, subvention receivables in connection with the Chrysler Agreement, investment and capital market receivables, and unapplied payments. Mortgage Servicing Residential real estateThe Company maintains an MSR asset for sold residential real estate loans serviced for others. At March 31, 2016 and December 31, 2015, the balance of these loans serviced for others was $15.8 billion, and $15.9 billion, respectively. The Company accounts for residential MSRs using the FVO. Changes in fair value are recorded through the Mortgage banking income, net line of the Condensed Consolidated Statements of Operations. The fair value of the MSRs at March 31, 2016 and December 31, 2015 were $130.7 million and $147.2 million, respectively. See further discussion on the valuation of the MSRs in Note 16. As deemed appropriate, the Company economically hedges MSRs using interest rate swaps and forward contracts to purchase MBS. See further discussion on these derivative activities in Note 11 to these Condensed Consolidated Financial Statements. NOTE 8. OTHER ASSETS (continued)For the three-month periods endedMarch 31, 2016 and March 31, 2015, the Company recorded net changes in the fair value of MSRs due to valuation totaling $(14.4) million and $(7.0) million, respectively.The following table presents a summary of year to date activity for the Company's residential MSRs that are included in the Condensed Consolidated Balance Sheets. Three-Month Period Ended March 31, 2016 March 31, 2015 (in thousands)Fair value at beginning of period$147,233 $145,047Mortgage servicing assets recognized3,591 3,526Principal reductions(5,726) (6,131)Change in fair value due to valuation assumptions(14,356) (6,990)Fair value at end of period$130,742 $135,452Fee income and gain/loss on sale of mortgage loansIncluded in Mortgage banking income, net on the Condensed Consolidated Statements of Operations was mortgage servicing fee income of $10.8 million for the three-month period endedMarch 31, 2016, compared to $11.2 million for the corresponding period in 2015. The Company had gains on sales of mortgage loans included in Mortgage banking income, net on the Condensed Consolidated Statements of Operations of $3.1 million and $6.2 million for the three-month periods endedMarch 31, 2016 and March 31, 2015, respectively. |

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| - Definition
The entire disclosure for other assets. This disclosure includes other current assets and other noncurrent assets.
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