Premises, Equipment, and Leases - Schedule of Lease Expense and Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lease cost
Operating lease cost	$ 45	$ 47	$ 48
Sublease income	(2)	(2)	(1)
Total lease cost	43	45	47
Other information
(Gain) loss on right-of-use asset impairment - operating leases	1	1	3
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	46	50	53
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	$ 11	$ 31	$ 19