Investment Securities (Summary Of Investment Securities Available-For-Sale In Unrealized Loss Positions) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Temporarily Impaired Less than 12 months, Fair Value	$ 1,434		$ 5,825
Temporarily Impaired Less than 12 Months, Unrealized Losses	11		187
Temporarily Impaired 12 months or more, Fair Value	3,656		182
Temporarily Impaired 12 Months or more, Unrealized Losses	119		12
Temporarily Impaired Total, Fair Value	5,090		6,007
Temporarily Impaired Total, Unrealized Losses	130		199
Residential Mortgage-Backed Securities
Temporarily Impaired Less than 12 months, Fair Value	1,434	[1]	5,825	[1]
Temporarily Impaired Less than 12 Months, Unrealized Losses	11	[1]	187	[1]
Temporarily Impaired 12 months or more, Fair Value	3,519	[1]	11	[1]
Temporarily Impaired 12 Months or more, Unrealized Losses	117	[1]	1	[1]
Temporarily Impaired Total, Fair Value	4,953	[1]	5,836	[1]
Temporarily Impaired Total, Unrealized Losses	128	[1]	188	[1]
State And Municipal Securities
Temporarily Impaired Less than 12 months, Fair Value	0	[2]	0	[2]
Temporarily Impaired Less than 12 Months, Unrealized Losses	0	[2]	0	[2]
Temporarily Impaired 12 months or more, Fair Value	23	[2]	22	[2]
Temporarily Impaired 12 Months or more, Unrealized Losses	1	[2]	2	[2]
Temporarily Impaired Total, Fair Value	23	[2]	22	[2]
Temporarily Impaired Total, Unrealized Losses	1	[2]	2	[2]
Corporate Debt Securities
Temporarily Impaired Less than 12 months, Fair Value	0	[2]	0	[2]
Temporarily Impaired Less than 12 Months, Unrealized Losses	0	[2]	0	[2]
Temporarily Impaired 12 months or more, Fair Value	1	[2]	1	[2]
Temporarily Impaired 12 Months or more, Unrealized Losses	0	[2],[3]	0	[2],[3]
Temporarily Impaired Total, Fair Value	1	[2]	1	[2]
Temporarily Impaired Total, Unrealized Losses	0	[2],[3]	0	[2],[3]
Equity and Other Non-Debt Securities
Temporarily Impaired Less than 12 months, Fair Value	0	[2]	0	[2]
Temporarily Impaired Less than 12 Months, Unrealized Losses	0	[2]	0	[2]
Temporarily Impaired 12 months or more, Fair Value	113	[2]	148	[2]
Temporarily Impaired 12 Months or more, Unrealized Losses	1	[2]	9	[2]
Temporarily Impaired Total, Fair Value	113	[2]	148	[2]
Temporarily Impaired Total, Unrealized Losses	$ 1	[2]	$ 9	[2]

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

[2] Auction-rate securities.

[3] Unrealized losses less than $0.5 million.