DERIVATIVES - Effect of Customer Derivatives and Economic Hedges on Net Income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income		$ 6	$ 4
Customer derivative contracts | Noninterest Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[1]	97	73
Customer derivative contracts | Noninterest Income | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[1]	51	(35)
Customer derivative contracts | Mortgage Banking Fees | Residential loan commitments
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[2]	4	0
Economic hedges | Noninterest Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[1]	(91)	(68)
Economic hedges | Foreign Exchange and Trade Finance Fees | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[3]	(50)	35
Economic hedges | Mortgage Banking Fees | Forward sale contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Recognized in Noninterest Income	[2]	$ (5)	$ (1)

[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 letter of credit fees on the Consolidated Statements of Operations.