Selected Quarterly Financial Data (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net interest income	$ 569	$ 543	$ 673	$ 519	$ 526	$ 492	$ 518	$ 505	$ 2,304	[1]	$ 2,041	[1]	$ 2,158	[1]
Provision for credit losses	64	23	85	16	51	54	67	21	188		193		293
Net interest income after provision for credit losses	505	520	588	503	475	438	451	484	2,116		1,848		1,865
Other revenues	459	386	261	500	267	432	566	592	1,606		1,857		1,973
Operating expenses	864	934	876	750	1,519	834	766	768	3,424	[2]	3,887	[2]	4,664	[2]
Income (loss) from continuing operations before income tax	100	(28)	(27)	253	(777)	36	251	308	298		(182)		(826)
Income tax expense (benefit)	30	(29)	(206)	149	(72)	32	71	125	(56)		156		422
Net income (loss)	$ 70	$ 1	$ 179	$ 104	$ (705)	$ 4	$ 180	$ 183	$ 354		$ (338)		$ (1,045)

[1] Net interest income of each segment represents the difference between actual interest earned on assets and interest paid on liabilities of the segment adjusted for a funding charge or credit. Segments are charged a cost to fund assets (e.g. customer loans) and receive a funding credit for funds provided (e.g. customer deposits) based on equivalent market rates. The objective of these charges/credits is to transfer interest rate risk from the segments to one centralized unit in Balance Sheet Management and more appropriately reflect the profitability of segments.

[2] Expenses for the segments include fully apportioned corporate overhead expenses.