Securities - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) security	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) security	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) security
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Number of available-for-sale debt securities in an unrealized loss position | security	481		481		547
Debt Securities, AFS, allowance for credit loss | $	$ 0		$ 0		$ 0
Provision (reversal of provision) for credit losses | $	0	$ 0	0	$ 0
HTM securities allowance for credit loss | $	0		0		0
Asset Pledged as Collateral
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
AFS and HTM debt securities carrying value | $	$ 5,800,000,000		$ 5,800,000,000		$ 7,000,000,000.0
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Number of available-for-sale debt securities in an unrealized loss position | security	240		240		255
Non-agency mortgage-backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Number of available-for-sale debt securities in an unrealized loss position | security	88		88		99
Corporate debt securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Number of available-for-sale debt securities in an unrealized loss position | security	54		54		66