Allowance for Credit Losses - Allowance for Credit Losses and Liability for Off-balance Sheet Credit Exposures (Details) - USD ($)	Sep. 30, 2024		Jun. 30, 2024	Dec. 31, 2023		Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Credit Loss [Abstract]
Loans	$ 547,000,000	[1]	$ 583,000,000	$ 591,000,000	[1]	$ 576,000,000	$ 605,000,000	$ 584,000,000
Securities held-to-maturity	0			0
Other financial assets measured at amortized cost	0			0
Securities available-for-sale	0			0
Total allowance for credit losses	547,000,000			591,000,000
Liability for off-balance sheet credit exposures	$ 135,000,000		$ 118,000,000	$ 111,000,000		$ 133,000,000	$ 143,000,000	$ 117,000,000

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at September 30, 2024 and December 31, 2023. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 15, "Variable Interest Entities," for additional information. September 30, 2024December 31, 2023(in millions)AssetsOther assets$13 $23 Total assets$13 $23 LiabilitiesInterest, taxes and other liabilities$21 $17 Total liabilities$21 $17