Investment Securities (Summary Of Investment Securities Available-For-Sale) (Details) - USD ($) $ in Millions		Sep. 30, 2017	Dec. 31, 2016
Investment securities available-for-sale, Amortized Cost	[1]	$ 11,022	$ 10,829
Investment securities available-for-sale securities, Gross Unrealized Gains	[1]	54	57
Investment securities available-for-sale securities, Gross Unrealized Losses	[1]	78	99
Investment securities available-for-sale, Fair Value	[1]	10,998	10,787
Investment securities held-to-maturity, Amortized Cost		1,344	1,582
Investment securities held-to-maturity, Fair Value		1,339
Net unrealized losses on available-for-sale securities transferred to held-to-maturity		(9)	12
U.S. Treasury and other U.S. government agency securities
Investment securities available-for-sale, Amortized Cost		2,763	2,772
Investment securities available-for-sale securities, Gross Unrealized Gains		8	8
Investment securities available-for-sale securities, Gross Unrealized Losses		1	1
Investment securities available-for-sale, Fair Value		2,770	2,779
Residential mortgage-backed securities
Investment securities available-for-sale, Amortized Cost	[2]	8,168	7,921
Investment securities available-for-sale securities, Gross Unrealized Gains	[2]	44	48
Investment securities available-for-sale securities, Gross Unrealized Losses	[2]	75	97
Investment securities available-for-sale, Fair Value	[2]	8,137	7,872
Investment securities held-to-maturity, Amortized Cost	[2],[3]	1,344	1,582
Investment securities held-to-maturity, Gross Unrealized Gains	[2],[3]	1	1
Investment securities held-to-maturity, Gross Unrealized Losses	[2],[3]	6	7
Investment securities held-to-maturity, Fair Value	[2],[3]	1,339	1,576
State and municipal securities
Investment securities available-for-sale, Amortized Cost		5	7
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		5	7
Equity and other non-debt securities
Investment securities available-for-sale, Amortized Cost		86	129
Investment securities available-for-sale securities, Gross Unrealized Gains		2	1
Investment securities available-for-sale securities, Gross Unrealized Losses		2	1
Investment securities available-for-sale, Fair Value		86	129
Auction-rate securities
Investment securities available-for-sale, Amortized Cost		52	55
Investment securities available-for-sale, Fair Value		$ 50	$ 54

[1] Included auction-rate securities at amortized cost and fair value of $52 million and $50 million, respectively as of September 30, 2017 and $55 million and $54 million, respectively, as of December 31, 2016.

[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 $9 million at September 30, 2017 and $12 million at December 31, 2016 related to securities transferred from available-for-sale, which are included in accumulated other comprehensive loss.