BUSINESS SEGMENTS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net interest income	$ 836	$ 808
Noninterest income	347	358
Total revenue	1,183	1,166
Noninterest expense	810	810
Profit (loss) before provision for credit losses	373	356
Provision for credit losses	58	121
Income before income tax expense	315	235
Income tax expense	106	69
NET INCOME	209	166
Total Average Assets	133,325	123,904
Consumer Banking
Segment Reporting Information [Line Items]
Net interest income	533	537
Noninterest income	219	219
Total revenue	752	756
Noninterest expense	596	638
Profit (loss) before provision for credit losses	156	118
Provision for credit losses	63	70
Income before income tax expense	93	48
Income tax expense	32	16
NET INCOME	61	32
Total Average Assets	51,602	47,610
Commercial Banking
Segment Reporting Information [Line Items]
Net interest income	276	256
Noninterest income	100	107
Total revenue	376	363
Noninterest expense	173	153
Profit (loss) before provision for credit losses	203	210
Provision for credit losses	(21)	(5)
Income before income tax expense	224	215
Income tax expense	77	74
NET INCOME	147	141
Total Average Assets	41,606	36,955
Other
Segment Reporting Information [Line Items]
Net interest income	27	15
Noninterest income	28	32
Total revenue	55	47
Noninterest expense	41	19
Profit (loss) before provision for credit losses	14	28
Provision for credit losses	16	56
Income before income tax expense	(2)	(28)
Income tax expense	(3)	(21)
NET INCOME	1	(7)
Total Average Assets	$ 40,117	$ 39,339