RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME - Effects to Net Income of Amounts Reclassified Out of OCI (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net interest income	$ 820	$ 770	$ 2,461	$ 2,279
Provision for credit losses	77	145	247	347
Noninterest income	341	383	1,339	1,253
Noninterest expense	810	788	2,568	6,861
Income before income tax expense (benefit)	274	220	985	(3,676)
Income tax expense (benefit)	85	76	317	(98)
Net income (loss)	189	144	668	(3,578)
Amount Reclassified from OCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net interest income	820	770	2,461	2,279
Provision for credit losses	77	145	247	347
Noninterest income	341	383	1,339	1,253
Noninterest expense	810	788	2,568	6,861
Income before income tax expense (benefit)	274	220	985	(3,676)
Income tax expense (benefit)	85	76	317	(98)
Net income (loss)	189	144	668	(3,578)
Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net interest income	(5)	(30)	(25)	(122)
Noninterest income	1	22	20	110
Noninterest expense	(52)	3	(49)	9
Income tax expense (benefit)	16	(5)	15	(8)
Net income (loss)	32	(6)	29	(13)
Net Unrealized Gains (Losses) on Derivatives | Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income tax expense (benefit)	(5)	(30)	(25)	(124)
Income tax expense (benefit)	2	11	9	45
Net income (loss)	$ (3)	$ (19)	$ (16)	$ (79)