Investment Securities (Summary Of Investment Securities Available-For-Sale) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Amortized Cost	$ 9,491	[1]	$ 9,414	[1]
Gross Unrealized Gains	107	[1]	92	[1]
Gross Unrealized Losses	130	[1]	199	[1]
Investment securities available-for-sale	9,468	[1]	9,307	[1]
U.S. Treasury and Other U.S. Government Agency Securities
Amortized Cost	45		45
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Investment securities available-for-sale	45		45
Residential Mortgage-Backed Securities
Amortized Cost	9,131	[2]	9,023	[2]
Gross Unrealized Gains	106	[2]	91	[2]
Gross Unrealized Losses	128	[2]	188	[2]
Investment securities available-for-sale	9,109	[2]	8,926	[2]
State And Municipal Securities
Amortized Cost	24		24
Gross Unrealized Gains	0		0
Gross Unrealized Losses	1		2
Investment securities available-for-sale	23		22
Corporate Debt Securities
Amortized Cost	53		56
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Investment securities available-for-sale	53		56
Equity and Other Non-Debt Securities
Amortized Cost	238		266
Gross Unrealized Gains	1		1
Gross Unrealized Losses	1		9
Investment securities available-for-sale	238		258
Auction-Rate Securities
Amortized Cost	138		169
Investment securities available-for-sale	$ 137		$ 159

[1] Included auction-rate securities at amortized cost and fair value of $138 million and $137 million, respectively, as of September 30, 2014 and $169 million and $159 million, respectively, as of December 31, 2013.

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