Investment Securities (Summary Of Investment Securities) (Details) $ in Millions	Dec. 31, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Investment securities available-for-sale, Amortized Cost	$ 19,541	$ 22,045
Investment securities available-for-sale, Gross Unrealized Gains	0	0
Investment securities available-for-sale, Gross Unrealized Losses	2,672	3,033
Investment securities available-for-sale, Fair Value	16,869	19,012
Debt Securities, Available-for-Sale, Unrealized Loss Position	16,867	19,010
Temporarily Impaired Total, Unrealized Losses	$ 2,672	$ 3,033
Debt Securities Count \| security	1,250	1,289
Temporarily Impaired Less than 12 Months, Fair Value	$ 10	$ 8,504
Temporarily Impaired, Less than 12 Months, Unrealized Losses	0	771
Temporarily Impaired 12 Months or more, Fair Value	16,857	10,506
Temporarily Impaired, 12 Months or more, Unrealized Losses	2,672	2,262
U.S. Treasury and other U.S. government agency securities
Investment securities available-for-sale, Amortized Cost	1,681	2,810
Investment securities available-for-sale, Gross Unrealized Gains	0	0
Investment securities available-for-sale, Gross Unrealized Losses	76	146
Investment securities available-for-sale, Fair Value	1,605	2,664
Debt Securities, Available-for-Sale, Unrealized Loss Position	1,605	2,664
Temporarily Impaired Total, Unrealized Losses	$ 76	$ 146
Debt Securities Count	19	27
Temporarily Impaired Less than 12 Months, Fair Value	$ 0	$ 996
Temporarily Impaired 12 Months or more, Fair Value	1,605	1,668
Temporarily Impaired, 12 Months or more, Unrealized Losses	76	141
Residential mortgage-backed securities
Investment securities available-for-sale, Amortized Cost	12,607	13,983
Investment securities available-for-sale, Gross Unrealized Gains	0	0
Investment securities available-for-sale, Gross Unrealized Losses	2,088	2,328
Investment securities available-for-sale, Fair Value	10,519	11,655
Debt Securities, Available-for-Sale, Unrealized Loss Position	10,517	11,653
Temporarily Impaired Total, Unrealized Losses	$ 2,088	$ 2,328
Debt Securities Count	978	1,008
Temporarily Impaired Less than 12 Months, Fair Value	$ 10	$ 3,500
Temporarily Impaired 12 Months or more, Fair Value	10,507	8,153
Temporarily Impaired, 12 Months or more, Unrealized Losses	2,088	1,967
Commercial Mortgage Backed Securities
Investment securities available-for-sale, Amortized Cost	5,253	5,252
Investment securities available-for-sale, Gross Unrealized Gains	0	0
Investment securities available-for-sale, Gross Unrealized Losses	508	559
Investment securities available-for-sale, Fair Value	4,745	4,693
Debt Securities, Available-for-Sale, Unrealized Loss Position	4,745	4,693
Temporarily Impaired Total, Unrealized Losses	$ 508	$ 559
Debt Securities Count	253	254
Temporarily Impaired Less than 12 Months, Fair Value	$ 0	$ 4,008
Temporarily Impaired 12 Months or more, Fair Value	4,745	685
Temporarily Impaired, 12 Months or more, Unrealized Losses	$ 508	$ 154

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