CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net unrealized derivative instrument gains arising during the periods, tax	$ 30	$ 10	$ 66	$ 80
Reclassification adjustment for net derivative (losses) gains included in net income, tax	(3)	2	(5)	9
Net unrealized securities available for sale gains (losses) arising during the periods, tax	37	(36)	25	73
Other-than-temporary impairment not recognized in earnings on securities, tax	(4)	0	(15)	(12)
Reclassification of net securities gains to net income, tax	0	0	(5)	(7)
Actuarial loss, tax	0	(35)	0	(35)
Net prior service credit, tax	0	3	0	3
Amortization of actuarial loss, tax	0	1	3	2
Divestitures to RBS effective September 1, 2014, tax	$ 0	$ 13	$ 0	$ 13