SECURITIES - Schedule of Investments (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Equity Securities Available-for-sale, Amortized Cost	$ 18,553	$ 16,010
Equity Securities Available-for-sale, Gross Unrealized Gains	216	159
Equity Securities Available-for-sale, Gross Unrealized Losses	(103)	(174)
Equity Securities Available-for-sale, Fair Value	18,666	15,995
Securities Held-to-maturity, Amortized Cost	5,289	4,315
Securities Held-to-maturity, Gross Unrealized Gain	35	0
Securities Held-to-maturity, Gross Unrealized Losses	(46)	(58)
Securities held-to-maturity, Fair Value	5,278	4,257
Other Investment Securities, Amortized Cost	893	935
Other Investment Securities, Gross Unrealized Gains	0	0
Other Investment Securities, Gross Unrealized Losses	0	0
Other Investment Securities, Fair Value	893	935
U.S. Treasury
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities Available-for-sale, Amortized Cost	15	15
Debt Securities Available-for-sale, Gross Unrealized Gains	0	0
Debt Securities Available-for-sale, Gross Unrealized Losses	0	0
Debt Securities Available-for-sale, Fair Value	15	15
State and political subdivisions
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities Available-for-sale, Amortized Cost	10	11
Debt Securities Available-for-sale, Gross Unrealized Gains	0	0
Debt Securities Available-for-sale, Gross Unrealized Losses	0	(1)
Debt Securities Available-for-sale, Fair Value	10	10
Federal agencies and U.S. government sponsored entities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities Available-for-sale, Amortized Cost	17,759	14,970
Debt Securities Available-for-sale, Gross Unrealized Gains	207	151
Debt Securities Available-for-sale, Gross Unrealized Losses	(68)	(128)
Debt Securities Available-for-sale, Fair Value	17,898	14,993
Securities Held-to-maturity, Amortized Cost	3,833	2,940
Securities Held-to-maturity, Gross Unrealized Gain	9	0
Securities Held-to-maturity, Gross Unrealized Losses	(46)	(33)
Securities held-to-maturity, Fair Value	3,796	2,907
Other/non-agency
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities Available-for-sale, Amortized Cost	747	992
Debt Securities Available-for-sale, Gross Unrealized Gains	6	5
Debt Securities Available-for-sale, Gross Unrealized Losses	(35)	(45)
Debt Securities Available-for-sale, Fair Value	718	952
Securities Held-to-maturity, Amortized Cost	1,456	1,375
Securities Held-to-maturity, Gross Unrealized Gain	26	0
Securities Held-to-maturity, Gross Unrealized Losses	0	(25)
Securities held-to-maturity, Fair Value	1,482	1,350
Total mortgage-backed securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities Available-for-sale, Amortized Cost	18,506	15,962
Debt Securities Available-for-sale, Gross Unrealized Gains	213	156
Debt Securities Available-for-sale, Gross Unrealized Losses	(103)	(173)
Debt Securities Available-for-sale, Fair Value	18,616	15,945
Total debt securities available for sale
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Debt Securities Available-for-sale, Amortized Cost	18,531	15,988
Debt Securities Available-for-sale, Gross Unrealized Gains	213	156
Debt Securities Available-for-sale, Gross Unrealized Losses	(103)	(174)
Debt Securities Available-for-sale, Fair Value	18,641	15,970
Marketable equity securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Equity Securities Available-for-sale, Amortized Cost	10	10
Equity Securities Available-for-sale, Gross Unrealized Gains	3	3
Equity Securities Available-for-sale, Gross Unrealized Losses	0	0
Equity Securities Available-for-sale, Fair Value	13	13
Other equity securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Equity Securities Available-for-sale, Amortized Cost	12	12
Equity Securities Available-for-sale, Gross Unrealized Gains	0	0
Equity Securities Available-for-sale, Gross Unrealized Losses	0	0
Equity Securities Available-for-sale, Fair Value	12	12
Total equity securities available for sale
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Equity Securities Available-for-sale, Amortized Cost	22	22
Equity Securities Available-for-sale, Gross Unrealized Gains	3	3
Equity Securities Available-for-sale, Gross Unrealized Losses	0	0
Equity Securities Available-for-sale, Fair Value	25	25
Federal Reserve Bank stock
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Federal Reserve Bank Stock, Amortized Cost	470	462
Federal Reserve Bank Stock, Gross Unrealized Gains	0	0
Federal Reserve Bank Stock, Gross Unrealized Loss	0	0
Federal Reserve Bank Stock, Fair Value	470	462
Federal Home Loan Bank stock
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Federal Home Loan Bank Stock, Amortized Cost	417	468
Federal Home Loan Bank Stock, Gross Unrealized Gain	0	0
Federal Home Loan Bank Stock, Gross Unrealized Loss	0	0
Federal Home Loan Bank Stock, Fair Value	417	468
Total other investment securities
Schedule of Available-for-sale and Held-to-maturity Securities [Line Items]
Venture Capital, Amortized Cost	6	5
Venture Capital, Gross Unrealized Gain	0	0
Venture Capital, Gross Unrealized Loss	0	0
Venture Capital, Fair Value	$ 6	$ 5