Investment Securities (Investment Securities Available-for-Sale in an Unrealized Loss Position) (Details) (USD $) In Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2011		Dec. 31, 2010
Unrealized loss position, Impaired Less than 12 months, Fair Value	$ 1,263		$ 1,702
Unrealized loss position, Impaired Less than 12 months, Unrealized Losses	11		39
Unrealized loss position, Impaired 12 months or more, Fair Value	370		474
Unrealized loss position, Impaired 12 months or more, Unrealized Losses	38		37
Impaired, Total Fair Value	1,633		2,176
Impaired, Total Unrealized Losses	49		76
Residential Mortgage-Backed Securities [Member]
Unrealized loss position, Impaired Less than 12 months, Fair Value	1,263	[1]	1,702	[1]
Unrealized loss position, Impaired Less than 12 months, Unrealized Losses	11	[1]	39	[1]
Impaired, Total Fair Value	1,263	[1]	1,702	[1]
Impaired, Total Unrealized Losses	11	[1]	39	[1]
State And Municipal Securities [Member]
Unrealized loss position, Impaired 12 months or more, Fair Value	25	[2]	38	[2]
Unrealized loss position, Impaired 12 months or more, Unrealized Losses	6	[2]	7	[2]
Impaired, Total Fair Value	25	[2]	38	[2]
Impaired, Total Unrealized Losses	6	[2]	7	[2]
Auction-Rate Preferred Securities [Member]
Unrealized loss position, Impaired 12 months or more, Fair Value	345		436
Unrealized loss position, Impaired 12 months or more, Unrealized Losses	32		30
Impaired, Total Fair Value	345		436
Impaired, Total Unrealized Losses	$ 32		$ 30

[1] Residential mortgage-backed securities issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises.

[2] Primarily auction-rate securities.