Segment Information (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Number of Operating Segments									2
Segment Reporting Information [Line Items]
Net operating interest income									$ 1,086	$ 1,074	$ 969
Total non-interest income (loss)									342	740	754
Total net revenue	$ 454	$ 73	$ 445	$ 456	$ 461	$ 440	$ 438	$ 475	1,428	1,814	1,723
Provision (benefit) for loan losses									(40)	36	143
Total operating expense									1,207	1,145	1,275
Income (loss) before other income (expense) and income taxes									261	633	305
Total other income (expense)									(170)	(181)	(110)
Income (loss) before income taxes									91	452	195
Income tax expense (benefit)									(177)	159	109
Net income	89	(153)	$ 292	40	41	$ 86	$ 69	$ 97	268	293	86
Total assets	45,427				45,530				45,427	45,530	46,280
Extinguishment of Debt Disclosures [Abstract]
Reclassification of deferred losses on cash flow hedges		(370)							(370)	0	0
Losses on early extinguishment of debt		$ (39)		$ (73)					(112)	(71)	0
Corporate/Other
Segment Reporting Information [Line Items]
Net operating interest income									1	1	0
Total non-interest income (loss)									0	0	0
Total net revenue									1	1	0
Total operating expense									275	231	213
Income (loss) before other income (expense) and income taxes									(274)	(230)	(213)
Total other income (expense)									(170)	(181)	(110)
Income (loss) before income taxes									(444)	(411)	(323)
Total assets	595				423				595	423	676
Trading And Investing | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net operating interest income									702	618	527
Total non-interest income (loss)									667	697	690
Total net revenue									1,369	1,315	1,217
Total operating expense									827	766	883
Income (loss) before other income (expense) and income taxes									542	549	334
Income (loss) before income taxes									542	549	334
Total assets	11,554				12,032				11,554	12,032	10,820
Balance Sheet Management | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net operating interest income									383	455	442
Total non-interest income (loss)									(325)	43	64
Total net revenue									58	498	506
Provision (benefit) for loan losses									(40)	36	143
Total operating expense									105	148	179
Income (loss) before other income (expense) and income taxes									(7)	314	184
Income (loss) before income taxes									(7)	314	184
Total assets	$ 33,278				$ 33,075				$ 33,278	$ 33,075	$ 34,784
Minimum [Member] | Customer Concentration Risk [Member] | Gross Revenues [Member]
Segment Reporting Information [Line Items]
Number Of Customer Accounts	0				0				0	0	0
Concentration Risk, Percentage									10.00%	10.00%	10.00%