Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Details) - Fair Value, Nonrecurring - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	$ 28	$ 108
Accrued income and other assets	80	56
Total assets on a recurring basis at fair value	108	164
Level 1
ASSETS MEASURED ON A NONRECURRING BASIS
Collateral-dependent loans	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
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	28	108
Accrued income and other assets	80	56
Total assets on a recurring basis at fair value	$ 108	$ 164