Investment Securities (Summary Of Investment Securities Available-For-Sale) (Details) - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Investment securities available-for-sale, Amortized Cost	[1]	$ 8,622	$ 8,035
Investment securities available-for-sale securities, Gross Unrealized Gains	[1]	147	123
Investment securities available-for-sale securities, Gross Unrealized Losses	[1]	20	42
Investment securities available-for-sale, Fair Value	[1]	8,749	8,116
Investment securities held-to-maturity, Amortized Cost		1,863	1,935
Investment securities held-to-maturity, Fair Value		1,872
Net unrealized losses on available-for-sale securities transferred to held-to-maturity		17	23
U.S. Treasury and Other U.S. Government Agency Securities
Investment securities available-for-sale, Amortized Cost		917	526
Investment securities available-for-sale securities, Gross Unrealized Gains		13	0
Investment securities available-for-sale securities, Gross Unrealized Losses		0	0
Investment securities available-for-sale, Fair Value		930	526
Residential Mortgage-Backed Securities
Investment securities available-for-sale, Amortized Cost	[2]	7,445	7,192
Investment securities available-for-sale securities, Gross Unrealized Gains	[2]	133	122
Investment securities available-for-sale securities, Gross Unrealized Losses	[2]	19	40
Investment securities available-for-sale, Fair Value	[2]	7,559	7,274
Investment securities held-to-maturity, Amortized Cost	[2],[3]	1,863	1,935
Investment securities held-to-maturity, Gross Unrealized Gains	[2],[3]	10	0
Investment securities held-to-maturity, Gross Unrealized Losses	[2],[3]	1	2
Investment securities held-to-maturity, Fair Value	[2],[3]	1,872	1,933
State And Municipal Securities
Investment securities available-for-sale, Amortized Cost		9	24
Investment securities available-for-sale securities, Gross Unrealized Gains		0	0
Investment securities available-for-sale securities, Gross Unrealized Losses		0	1
Investment securities available-for-sale, Fair Value		9	23
Corporate Debt Securities
Investment securities available-for-sale, Amortized Cost		45	51
Investment securities available-for-sale securities, Gross Unrealized Gains		0	0
Investment securities available-for-sale securities, Gross Unrealized Losses		0	0
Investment securities available-for-sale, Fair Value		45	51
Equity and Other Non-Debt Securities
Investment securities available-for-sale, Amortized Cost		206	242
Investment securities available-for-sale securities, Gross Unrealized Gains		1	1
Investment securities available-for-sale securities, Gross Unrealized Losses		1	1
Investment securities available-for-sale, Fair Value		206	242
Auction-Rate Securities
Investment securities available-for-sale, Amortized Cost		80	137
Investment securities available-for-sale, Fair Value		$ 79	$ 136

[1] Included auction-rate securities at amortized cost and fair value of $80 million and $79 million, respectively as of September 30, 2015 and $137 million and $136 million, respectively, as of December 31, 2014.

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

[3] The amortized cost of investment securities held-to-maturity included net unrealized losses of $17 million at September 30, 2015 and $23 million at December 31, 2014 related to securities transferred from available-for-sale, which are included in accumulated other comprehensive loss.