Allowance for Credit Losses - Change in Liability for Off-balance Sheet Credit Exposures (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Balance at beginning of period	$ 125	$ 84	$ 117	$ 103
Provision charged (credited) to income	18	5	26	(14)
Balance at end of period	$ 143	$ 89	$ 143	$ 89