| **BORROWINGS (SHUSA) (Details) (SHUSA [Member], USD $)Share data in Millions, unless otherwise specified**                                                                                                                                                                                                                                                                                                                                                                                                                |               |               | 0 Months Ended |               |               |               |               |               |               | 0 Months Ended |        |     |             |     |        |     |         |     |        |     |            |     |            |            |
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| **Debt Instrument [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |          |          |           |          |          |          |          |          |          |           |   |     |        |     |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
| Senior notes, Balance                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |          |          |           | $ 599,258,000 | $ 598,965,000 | $ 474,666,000 | $ 474,306,000 | $ 499,232,000 | $ 499,148,000 |           |   |     |        |     |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
| Subordinated notes, due March 2020, Balance                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |          |          |           |          |          |          |          |          |          |           | 0      | [1] | 756,829,000 | [1] |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
| Subordinated debentures, Balance                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |          |          |           |          |          |          |          |          |          |           |   |     |        |     | 0      | [2] | 611,000 | [2] |   |     |       |     | 70,262,000 | 70,262,000 |   |   | 150,000,000 | 150,000,000 |   |   |
| Common securties, Balance                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |          |          |           |          |          |          |          |          |          |           |   |     |        |     |   |     |    |     | 0      | [2] | 24,742,000 | [2] |       |       | 10,000,000 | 10,000,000 |   |   | 4,640,000 | 4,640,000 |
| Total holding company borrowings and other debt obligations                                                                                                                                                                                                                                                                                                                                                                                                                                                               | 1,808,058,000 | 2,589,503,000 |           |          |          |          |          |          |          |           |   |     |        |     |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
| Effective Rate                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | 3.88%         | 4.50%         |           | 3.28%         | 3.28%         | 4.85%         | 4.85%         | 3.62%         | 3.62%         |           | 0.00%  | [1] | 5.96%       | [1] | 0.00%  | [2] | 12.84%  | [2] | 0.00%  | [2] | 4.38%      | [2] | 7.91%      | 7.91%      | 7.91% | 7.91% | 2.02% | 2.04% | 2.02% | 2.04% |
| Stated Rate                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |          |          |           | 3.00%         |          | 4.625%        |          | 3.45%         |          |           |   |     |        |     |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
| Subordinated debt converted, original value                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |          |          |           |          |          |          |          |          |          | 750,000,000    |   |     |        |     |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
| Number of shares issued upon conversion                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |          |          |           |          |          |          |          |          |          | 3.0            |   |     |        |     |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
| Amount of securities called and retired                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |          |          | $ 24,700,000   |          |          |          |          |          |          |           |   |     |        |     |   |     |    |     |   |     |       |     |       |       |   |   |   |   |   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| [1]On February 21, 2014, the subordinated note, with a value of $750.0 million, was converted to 3.0 million shares of SHUSA common stock.[2]In December 2012, a settlement agreement was executed with respect to the Company's Trust PIERS litigation. The settlement agreement required the Company to make additional offers to purchase the Trust PIERS until no Trust PIERS remain outstanding. On February 28, 2014, the Company called and retired the remaining PIERS securities in the amount of $24.7 million. |

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Common Securties
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| - Definition
Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.
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| - Definition
The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.
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| - Definition
The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.
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| - Definition
Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.
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| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
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| - Definition
Gross amount of debt extinguished.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.
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| - Definition
Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.
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