Other Assets - Schedule of Equity Securities without Readily Determinable Fair Value (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Other Assets [Abstract]
FRB stock	$ 425,000,000		$ 425,000,000		$ 392,000,000
FHLB stock	272,000,000		272,000,000		392,000,000
Equity investments without a readily determinable fair value
Cost basis at acquisition	78,000,000		78,000,000		74,000,000
Upward adjustments	53,000,000		53,000,000		51,000,000
Downward adjustments (including impairment)	(39,000,000)		(39,000,000)		(23,000,000)
Carrying amount, equity investments without a readily determinable fair value	92,000,000		92,000,000		102,000,000
Nonmarketable equity investments	789,000,000		789,000,000		$ 886,000,000
Upward adjustments	1,000,000	$ 0	2,000,000	$ 7,000,000
Downward adjustments (including impairment)	(5,000,000)	0	(19,000,000)	(17,000,000)
Impairment of FHLB and FRB stock	$ 0	$ 0	$ 0	$ 0