FAIR VALUE ELECTIONS (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Federal funds sold and securities borrowed or purchased under agreements to resell
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	$ (628)	$ (409)
Trading account assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	(190)	836
Investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	(39)	(50)
Corporate
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	72	77
Consumer loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	(155)	(104)
Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	(83)	(27)
Mortgage servicing rights
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	553	(427)
Certain mortgage loans held for sale
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	951	2,514
Certain equity method investments
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	(9)	3
Other assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	1,495	2,090
Total assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	555	2,440
Interest-bearing deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	166	(218)
Federal funds purchased and securities loaned or sold under agreements to repurchase
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	110	66
Trading account liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	30	(143)
Short-term borrowings
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	76	145
Long-term debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	113	(2,008)
Total liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions.
Fair value elections, changes in fair value gains (losses)	$ 495	$ (2,158)