Loans - Summary by Portfolio Segment (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Loan balances by portfolio segment
Retained loans	$ 712,898,000,000	$ 675,437,000,000	$ 718,997,000,000
Held-for-sale	5,781,000,000		2,626,000,000
At fair value	2,288,000,000		2,097,000,000
Total loans	720,967,000,000		723,720,000,000
Loans And Leases Receivable Deferred Costs	2,700,000,000		2,700,000,000
Loan purchases and sales, and reclassifications from retained loans to loans held-for-sale excludes loans recorded at fair value
Purchases	2,080,000,000	2,115,000,000
Sales	1,220,000,000	1,134,000,000
Retained loans reclassified to held-for-sale	985,000,000	2,089,000,000
Loan sales by portfolio segment [Abstract]
Net gains/(losses) on sales of loans (including lower of cost or fair value adjustments)	46,000,000	66,000,000
Wholesale
Loan balances by portfolio segment
Retained loans	283,653,000,000		278,395,000,000
Held-for-sale	4,925,000,000		2,524,000,000
At fair value	2,288,000,000		2,097,000,000
Total loans	290,866,000,000		283,016,000,000
Loan purchases and sales, and reclassifications from retained loans to loans held-for-sale excludes loans recorded at fair value
Purchases	321,000,000	123,000,000
Sales	863,000,000	877,000,000
Retained loans reclassified to held-for-sale	62,000,000	177,000,000
Loan sales by portfolio segment [Abstract]
Net gains/(losses) on sales of loans (including lower of cost or fair value adjustments)	32,000,000	61,000,000
Consumer Excluding Credit Card
Loan balances by portfolio segment
Retained loans	304,770,000,000		308,427,000,000
Held-for-sale	0		0
At fair value	0		0
Total loans	304,770,000,000		308,427,000,000
Loan purchases and sales, and reclassifications from retained loans to loans held-for-sale excludes loans recorded at fair value
Purchases	1,759,000,000	1,992,000,000
Sales	357,000,000	257,000,000
Retained loans reclassified to held-for-sale	0	0
Loan sales by portfolio segment [Abstract]
Net gains/(losses) on sales of loans (including lower of cost or fair value adjustments)	32,000,000	25,000,000
Credit Card
Loan balances by portfolio segment
Retained loans	124,475,000,000		132,175,000,000
Held-for-sale	856,000,000		102,000,000
At fair value	0		0
Total loans	125,331,000,000		132,277,000,000
Loan purchases and sales, and reclassifications from retained loans to loans held-for-sale excludes loans recorded at fair value
Purchases	0	0
Sales	0	0
Retained loans reclassified to held-for-sale	923,000,000	1,912,000,000
Loan sales by portfolio segment [Abstract]
Net gains/(losses) on sales of loans (including lower of cost or fair value adjustments)	$ (18,000,000)	$ (20,000,000)