Investment Securities (Summary Of Investment Securities Available-For-Sale) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Investment securities available-for-sale, Amortized Cost	[1]	$ 10,829	$ 10,491
Investment securities available-for-sale, Gross Unrealized Gains	[1]	57	79
Investment securities available-for-sale, Gross Unrealized Losses	[1]	99	51
Investment securities available-for-sale, Fair Value	[1]	10,787	10,519
Investment securities held-to-maturity, Amortized Cost		1,582	1,981
Investment securities held-to-maturity, Fair Value		1,576
Unrealized losses on available-for-sale securities transferred to held-to-maturity		12	15
U.S. Treasury and other U.S. government agency securities
Investment securities available-for-sale, Amortized Cost		2,772	2,769
Investment securities available-for-sale, Gross Unrealized Gains		8	1
Investment securities available-for-sale, Gross Unrealized Losses		1	7
Investment securities available-for-sale, Fair Value		2,779	2,763
Residential mortgage-backed securities
Investment securities available-for-sale, Amortized Cost	[2]		7,513
Investment securities available-for-sale, Gross Unrealized Gains	[2]	48	76
Investment securities available-for-sale, Gross Unrealized Losses	[2]	97	44
Investment securities available-for-sale, Fair Value	[2]	7,872	7,545
Investment securities held-to-maturity, Amortized Cost	[2],[3]		1,981
Investment securities held-to-maturity, Gross Unrealized Gains	[2],[3]	1	2
Investment securities held-to-maturity, Gross Unrealized Losses	[2],[3]	7	10
Investment securities held-to-maturity, Fair Value	[2],[3]	1,576	1,973
State and municipal securities
Investment securities available-for-sale, Amortized Cost		7	9
Investment securities available-for-sale, Gross Unrealized Gains		0	0
Investment securities available-for-sale, Gross Unrealized Losses		0	0
Investment securities available-for-sale, Fair Value		7	9
Corporate debt securities
Investment securities available-for-sale, Amortized Cost			1
Investment securities available-for-sale, Gross Unrealized Gains			0
Investment securities available-for-sale, Gross Unrealized Losses			0
Investment securities available-for-sale, Fair Value			1
Equity and other non-debt securities
Investment securities available-for-sale, Amortized Cost		129	199
Investment securities available-for-sale, Gross Unrealized Gains		1	2
Investment securities available-for-sale, Gross Unrealized Losses		1	0
Investment securities available-for-sale, Fair Value		129	201
Investment securities held-to-maturity, Amortized Cost		0
Investment securities held-to-maturity, Fair Value		0
Auction-rate securities
Investment securities available-for-sale, Amortized Cost		55	76
Investment securities available-for-sale, Fair Value		$ 54	$ 77

[1] Included auction-rate securities at amortized cost and fair value of $55 million and $54 million, respectively, as of December 31, 2016 and $76 million and $77 million, respectively, as of December 31, 2015.

[2] 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 $12 million at December 31, 2016 and $15 million at December 31, 2015 related to securities transferred from available-for-sale, which are included in accumulated other comprehensive loss.