DERIVATIVES - Effect of Customer Derivatives and Economic Hedges on Net Income (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total		$ 16,000,000	$ 4,000,000	$ 23,000,000	$ 21,000,000
Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total		16,000,000	0	22,000,000	0
Customer derivative contracts | Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total	[1]	85,000,000	2,000,000	149,000,000	151,000,000
Customer derivative contracts | Other Income | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total	[1]	(4,000,000)	(60,000,000)	(21,000,000)	(54,000,000)
Customer derivative contracts | Mortgage Banking Fees | Residential loan commitments
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total	[2]	9,000,000	(4,000,000)	2,000,000	4,000,000
Economic hedges | Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total	[1]	(75,000,000)	5,000,000	(126,000,000)	(130,000,000)
Economic hedges | Foreign Exchange and Trade Finance Fees | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total	[3]	5,000,000	59,000,000	21,000,000	52,000,000
Economic hedges | Mortgage Banking Fees | Forward sale contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income, Total	[2]	$ (4,000,000)	$ 2,000,000	$ (2,000,000)	$ (2,000,000)

[1] Reported in other income on the Consolidated Statements of Operations.

[2] Reported in mortgage banking fees on the Consolidated Statements of Operations.

[3] Reported in foreign exchange and trade finance fees on the Consolidated Statements of Operations.