Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	$ 96	$ 152
Loans held for sale	3	0
Accrued income and other assets	32	14
Total assets on a recurring basis at fair value	131	166
Level 1
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	0	0
Loans held for sale	0	0
Accrued income and other assets	0	0
Total assets on a recurring basis at fair value	0	0
Level 2
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	0	0
Loans held for sale	0	0
Accrued income and other assets	0	0
Total assets on a recurring basis at fair value	0	0
Level 3
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	96	152
Loans held for sale	3	0
Accrued income and other assets	32	14
Total assets on a recurring basis at fair value	$ 131	$ 166