Investment Securities (Summary Of Investment Securities In Unrealized Loss Positions) (Details)		Jun. 30, 2024 USD ($) security	Dec. 31, 2023 USD ($) security
Schedule of Investments [Line Items]
Less than 12 months, Fair Value		$ 37,000,000	$ 10,000,000
Less than 12 Months, Unrealized Losses		0	0
12 months or more, Fair Value		15,618,000,000	16,857,000,000
12 Months or more, Unrealized Losses		2,954,000,000	2,672,000,000
Total, Fair Value		15,655,000,000	16,867,000,000
Total, Unrealized Losses		$ 2,954,000,000	$ 2,672,000,000
Securities with no credit impairment in unrealized loss position		1,215	1,250
U.S. Treasury securities
Schedule of Investments [Line Items]
Less than 12 months, Fair Value		$ 35,000,000	$ 0
Less than 12 Months, Unrealized Losses		0	0
12 months or more, Fair Value		1,269,000,000	1,605,000,000
12 Months or more, Unrealized Losses		50,000,000	76,000,000
Total, Fair Value		1,304,000,000	1,605,000,000
Total, Unrealized Losses		$ 50,000,000	$ 76,000,000
Securities with no credit impairment in unrealized loss position | security		16	19
Residential mortgage-backed securities
Schedule of Investments [Line Items]
Less than 12 months, Fair Value	[1]	$ 2,000,000	$ 10,000,000
Less than 12 Months, Unrealized Losses	[1]	0	0
12 months or more, Fair Value	[1]	9,675,000,000	10,507,000,000
12 Months or more, Unrealized Losses	[1]	2,327,000,000	2,088,000,000
Total, Fair Value	[1]	9,677,000,000	10,517,000,000
Total, Unrealized Losses	[1]	$ 2,327,000,000	$ 2,088,000,000
Securities with no credit impairment in unrealized loss position | security	[1]	947	978
Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Less than 12 months, Fair Value	[1]	$ 0	$ 0
Less than 12 Months, Unrealized Losses	[1]	0	0
12 months or more, Fair Value	[1]	4,674,000,000	4,745,000,000
12 Months or more, Unrealized Losses	[1]	577,000,000	508,000,000
Total, Fair Value	[1]	4,674,000,000	4,745,000,000
Total, Unrealized Losses	[1]	$ 577,000,000	$ 508,000,000
Securities with no credit impairment in unrealized loss position | security	[1]	252	253

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