Investment Securities (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) security	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) security	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Schedule of Investments [Line Items]
Securities with no credit impairment in unrealized loss position | security	1,274		1,274
Loan interest receivable	$ 41		$ 41		$ 49
Securities gains and losses	0	$ 0	0	$ 0
Carrying value of securities pledged	17,000		17,000
Federal reserve bank pledges	8,900		8,900
Pledged to the FHLB as collateral for potential future borrowings	6,400		6,400
Collateral for potential future borrowings	1,700		1,700
Liabilities secured by pledged collateral	$ 784		$ 784
U.S. Treasury securities
Schedule of Investments [Line Items]
Securities with no credit impairment in unrealized loss position | security	20		20
Residential mortgage-backed securities
Schedule of Investments [Line Items]
Securities with no credit impairment in unrealized loss position | security	1,001		1,001
Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Securities with no credit impairment in unrealized loss position | security	253		253