FAIR VALUE MEASUREMENTS - Schedule of Financial Instruments not Recorded at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities held to maturity, carrying value	$ 4,992	$ 5,071
Securities held-to-maturity, fair value	4,995	5,058
Other investment securities, at cost, carrying value	939	942
Other investment securities, at cost, fair value	939	942
Other loans held for sale, carrying value	221	42
Other loans held for sale, fair value	221	42
Loans and leases, carrying value	108,111	107,669
Loans and leases, fair value	108,851	107,537
Deposits, carrying value	112,112	109,804
Deposits, fair value	112,096	109,796
Federal funds purchased and securities sold under agreements to repurchase, carrying value	1,093	1,148
Federal funds purchased and securities sold under agreements to repurchase, fair value	1,093	1,148
Other short-term borrowed funds, carrying value	2,762	3,211
Other short-term borrowed funds, fair value	2,762	3,211
Long-term borrowed funds, carrying value	11,780	12,790
Long-term borrowed funds, fair value	11,877	12,849
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities held to maturity, carrying value	0	0
Securities held-to-maturity, fair value	0	0
Other investment securities, at cost, carrying value	0	0
Other investment securities, at cost, fair value	0	0
Other loans held for sale, carrying value	0	0
Other loans held for sale, fair value	0	0
Loans and leases, carrying value	0	0
Loans and leases, fair value	0	0
Deposits, carrying value	0	0
Deposits, fair value	0	0
Federal funds purchased and securities sold under agreements to repurchase, carrying value	0	0
Federal funds purchased and securities sold under agreements to repurchase, fair value	0	0
Other short-term borrowed funds, carrying value	0	0
Other short-term borrowed funds, fair value	0	0
Long-term borrowed funds, carrying value	0	0
Long-term borrowed funds, fair value	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities held to maturity, carrying value	4,992	5,071
Securities held-to-maturity, fair value	4,995	5,058
Other investment securities, at cost, carrying value	939	942
Other investment securities, at cost, fair value	939	942
Other loans held for sale, carrying value	0	0
Other loans held for sale, fair value	0	0
Loans and leases, carrying value	366	355
Loans and leases, fair value	366	355
Deposits, carrying value	112,112	109,804
Deposits, fair value	112,096	109,796
Federal funds purchased and securities sold under agreements to repurchase, carrying value	1,093	1,148
Federal funds purchased and securities sold under agreements to repurchase, fair value	1,093	1,148
Other short-term borrowed funds, carrying value	2,762	3,211
Other short-term borrowed funds, fair value	2,762	3,211
Long-term borrowed funds, carrying value	11,780	12,790
Long-term borrowed funds, fair value	11,877	12,849
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities held to maturity, carrying value	0	0
Securities held-to-maturity, fair value	0	0
Other investment securities, at cost, carrying value	0	0
Other investment securities, at cost, fair value	0	0
Other loans held for sale, carrying value	221	42
Other loans held for sale, fair value	221	42
Loans and leases, carrying value	107,745	107,314
Loans and leases, fair value	108,485	107,182
Deposits, carrying value	0	0
Deposits, fair value	0	0
Federal funds purchased and securities sold under agreements to repurchase, carrying value	0	0
Federal funds purchased and securities sold under agreements to repurchase, fair value	0	0
Other short-term borrowed funds, carrying value	0	0
Other short-term borrowed funds, fair value	0	0
Long-term borrowed funds, carrying value	0	0
Long-term borrowed funds, fair value	$ 0	$ 0

Investments In Federal Home Loan Bank Stock, Amortized Cost Basis

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The amount of other loans receivable that will be sold to other entities.

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Fair value portion of other loans receivable held-for-sale.

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Fair value portion of short-term borrowings not otherwise specified in the taxonomy having initial terms less than one year or the normal operating cycle, if longer.

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No definition available.

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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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.

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No definition available.

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Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

+ References

No definition available.

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Amount after offset of short term borrowing where a bank borrows, at the federal funds rate, from another bank and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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- Definition

Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Amount of borrowings classified as other, maturing within one year or the normal operating cycle, if longer.

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