Allowance for Credit Losses - Allowance for Credit Losses and Liability for Off-balance Sheet Credit Exposures (Details) - USD ($)	Mar. 31, 2022		Dec. 31, 2021		Mar. 31, 2021	Dec. 31, 2020
Credit Loss [Abstract]
Loans	$ 467,000,000	[1]	$ 447,000,000	[1]	$ 853,000,000	$ 1,015,000,000
Securities held-to-maturity	1,000,000		1,000,000
Other financial assets measured at amortized cost	1,000,000		1,000,000
Securities available-for-sale	0		1,000,000
Total allowance for credit losses	469,000,000		450,000,000
Liability for off-balance sheet credit exposures	$ 84,000,000		$ 103,000,000		$ 155,000,000	$ 237,000,000

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at March 31, 2022 and December 31, 2021. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. March 31, 2022December 31, 2021(in millions)AssetsLoans$128 $46 Other assets51 55 Total assets$179 $101 LiabilitiesInterest, taxes and other liabilities$31 $9 Total liabilities$31 $9