Premises, Equipment, and Leases - Schedule of Lease Expense and Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Lease cost
Operating lease cost	$ 46	$ 44	$ 45
Sublease income	(1)	(1)	(2)
Total lease cost	45	43	43
Other information
(Gain) loss on right-of-use asset impairment - operating leases	1	0	1
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	34	43	46
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	$ 60	$ 22	$ 11