RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME - Reclassifications out of Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	$ 159		$ 149
Interest expense	(106)		(85)
Net impairment losses recognized in earnings	(1)		(4)
Salaries and employee benefits	419		405
Income before income tax expense	315		235
Income tax expense	106		69
NET INCOME	209		166
Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	3		2
NET INCOME	4		6
Reclassification adjustment for net derivative gains (losses) included in net income (loss): | Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income	18	[1]	18	[1]
Interest expense	(15)	[1]	(29)	[1]
Other income	0		0
Income before income tax expense	3		(11)
Income tax expense	1		(4)
NET INCOME	2		(7)
Reclassification of net securities gains (losses) to net income (loss): | Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Securities gains, net	8		25
Net impairment losses recognized in earnings	(1)		(4)
Income before income tax expense	7		21
Income tax expense	3		7
NET INCOME	4		14
Reclassification of changes related to defined benefit pension plans: | Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits	(3)		(2)
Income before income tax expense	(3)		(2)
Income tax expense	(1)		(1)
NET INCOME	$ (2)		$ (1)

[1] This amount includes both (a) the amortization of effective gains and losses associated with the Company’s terminated cash flow hedges and (b) the current reporting period’s interest settlements realized on the Company’s active cash flow hedges. Both (a) and (b) were previously included on the accumulated other comprehensive loss line item on the Consolidated Balance Sheets and were subsequently recorded as adjustments to the interest expense of the underlying hedged item.