Investment Securities (Summary Of Investment Securities In Unrealized Loss Positions) (Details) - USD ($) $ in Millions		Mar. 31, 2023	Dec. 31, 2022
Less than 12 months, Fair Value		$ 4,069	$ 8,504
Less than 12 Months, Unrealized Losses		236	771
12 months or more, Fair Value		14,220	10,506
12 Months or more, Unrealized Losses		2,488	2,262
Total, Fair Value		18,289	19,010
Total, Unrealized Losses		2,724	3,033
U.S. Treasury securities
Less than 12 months, Fair Value		299	996
Less than 12 Months, Unrealized Losses		1	5
12 months or more, Fair Value		1,685	1,668
12 Months or more, Unrealized Losses		118	141
Total, Fair Value		1,984	2,664
Total, Unrealized Losses		119	146
Residential mortgage-backed securities
Less than 12 months, Fair Value	[1]	728	3,500
Less than 12 Months, Unrealized Losses	[1]	40	361
12 months or more, Fair Value	[1]	10,797	8,153
12 Months or more, Unrealized Losses	[1]	2,094	1,967
Total, Fair Value	[1]	11,525	11,653
Total, Unrealized Losses	[1]	2,134	2,328
Commercial mortgage-backed securities
Less than 12 months, Fair Value	[1]	3,042	4,008
Less than 12 Months, Unrealized Losses	[1]	195	405
12 months or more, Fair Value	[1]	1,738	685
12 Months or more, Unrealized Losses	[1]	276	154
Total, Fair Value	[1]	4,780	4,693
Total, Unrealized Losses	[1]	$ 471	$ 559

[1] Issued and/or guaranteed by U.S. government agencies or U.S. government-sponsored enterprises.