CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - 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, 2012		0	560
Beginning balance at Dec. 31, 2012	$ 24,129	$ 0	$ 6	$ 18,589	$ 5,846	$ 0	$ (312)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to RBS	(185)				(185)
Dividends to RBS — exchange transactions	(1,000)				(1,000)
Capital contribution	14			14
Employee stock purchase plan shares purchased	0
Total comprehensive income:
Net income (loss)	(3,426)				(3,426)
Other comprehensive income (loss)	(336)						(336)
Total comprehensive income (loss)	(3,762)				(3,426)		(336)
Ending balance (in shares) at Dec. 31, 2013		0	560
Ending balance at Dec. 31, 2013	19,196	$ 0	$ 6	18,603	1,235	0	(648)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders	(16)				(16)
Dividends to RBS	(124)				(124)
Dividends to RBS — exchange transactions	(666)				(666)
Common shares repurchased from RBS (in shares)			(14)
Common shares repurchased from RBS	(334)					(334)
Share-based compensation plans	69			71		(2)
Employee stock purchase plan shares purchased	2			2
Total comprehensive income:
Net income (loss)	865				865
Other comprehensive income (loss)	276						276
Total comprehensive income (loss)	1,141				865		276
Ending balance (in shares) at Dec. 31, 2014		0	546
Ending 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	(143)				(143)
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	18			40		(22)
Employee stock purchase plan shares purchased	9			9
Total comprehensive income:
Net income (loss)	840				840
Other comprehensive income (loss)	(15)						(15)
Total comprehensive income (loss)	825				840		(15)
Ending balance (in shares) at Dec. 31, 2015		0	528
Ending balance at Dec. 31, 2015	$ 19,646	$ 247	$ 6	$ 18,725	$ 1,913	$ (858)	$ (387)