DERIVATIVES - Effect of Customer Derivatives and Economic Hedges on Net Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ 33		$ 70		$ 26
Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(4)		0
Customer derivative contracts | Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	240	[1]	79	[1]	292	[1]
Customer derivative contracts | Other Income | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(59)	[1]	18	[1]	10	[1]
Customer derivative contracts | Mortgage Banking Fees | Residential loan commitments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	6	[2]	(7)	[2]	11	[2]
Economic hedges | Other Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(209)	[1]	(30)	[1]	(285)	[1]
Economic hedges | Foreign Exchange and Trade Finance Fees | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	58	[3]	(15)	[3]	(10)	[3]
Economic hedges | Mortgage Banking Fees | Forward sale contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ (3)	[2]	$ 25	[2]	$ 8	[2]

[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.