CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) shares in Millions, $ in Millions	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock, at Cost	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2013		0	560
Beginning balance at Dec. 31, 2013	$ 19,196	$ 0	$ 6	$ 18,603	$ 1,235	$ 0	$ (648)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to RBS	(85)				(85)
Dividends to RBS — exchange transactions	(666)				(666)
Share-based compensation plans	57			57
Total comprehensive income:
Net income	668				668
Other comprehensive income	213						213
Total comprehensive income	881				668		213
Ending balance (in shares) at Sep. 30, 2014		0	560
Ending balance at Sep. 30, 2014	19,383	$ 0	$ 6	18,660	1,152	0	(435)
Beginning balance (in shares) at Dec. 31, 2014		0	546
Beginning balance at Dec. 31, 2014	19,268	$ 0	$ 6	18,676	1,294	(336)	(372)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders	(90)				(90)
Dividends to RBS	(71)				(71)
Dividend to preferred stockholders	(7)				(7)
Issuance of preferred stock (in shares)		0
Issuance of preferred stock	247	$ 247
Treasury stock purchased (in shares)			(20)
Treasury stock purchased	(500)					(500)
Share-based compensation plans (in shares)			2
Share-based compensation plans	14			35		(21)
Employee stock purchase plan shares issued	7			7
Total comprehensive income:
Net income	619				619
Other comprehensive income	113						113
Total comprehensive income	732				619		113
Ending balance (in shares) at Sep. 30, 2015		0	528
Ending balance at Sep. 30, 2015	$ 19,600	$ 247	$ 6	$ 18,718	$ 1,745	$ (857)	$ (259)