Other Assets - Schedule of Equity Securities without Readily Determinable Fair Value (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Other Assets [Abstract]
FRB stock	$ 432,000,000		$ 432,000,000		$ 440,000,000
FHLB stock	290,000,000		290,000,000		258,000,000
Equity investments without a readily determinable fair value
Cost basis	84,000,000		84,000,000		74,000,000
Upward adjustments	53,000,000		53,000,000		53,000,000
Downward adjustments (including impairment)	(38,000,000)		(38,000,000)		(36,000,000)
Carrying amount, equity investments without a readily determinable fair value	99,000,000		99,000,000		91,000,000
Nonmarketable equity investments	821,000,000		821,000,000		$ 789,000,000
Upward adjustments	0	$ 0	0	$ 1,000,000
Downward adjustments (including impairment)	(2,000,000)	(14,000,000)	(2,000,000)	(14,000,000)
Impairment of FHLB and FRB stock	$ 0	$ 0	$ 0	$ 0