Deposits - Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2023 USD ($)		Dec. 31, 2023 USD ($)		Dec. 31, 2022 USD ($)		Dec. 31, 2021 USD ($)	Nov. 30, 2023 quarterlyAssessmentPeriod
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Deposits	$ 121,283	[1]	$ 121,283	[1]	$ 123,223	[1]	$ 143,032
Overdraft deposits	91		91		205
FDIC assessment fees	243
Number of quarterly assessment periods | quarterlyAssessmentPeriod								8
Other Expense
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
FDIC assessment fees			322		54		$ 63
Deposits
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Deposits, fair value	$ 1,821		$ 1,821		$ 1,554

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at December 31, 2023 and 2022. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 27, "Variable Interest Entities," for additional information. At December 31,20232022(in millions)AssetsLoans, net$— $162 Other assets23 44 Total assets$23 $206 LiabilitiesInterest, taxes and other liabilities$17 $22 Total liabilities$17 $22