Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	$ 37	$ 28
Loans held for sale	51	0
Accrued income and other assets	12	80
Total assets at fair value	100	108
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 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 at fair value	0	0
Level 3
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	37	28
Loans held for sale	51	0
Accrued income and other assets	12	80
Total assets at fair value	$ 100	$ 108