Sale of Certain Branch Assets and Liabilities - Narrative (Details) $ in Millions		3 Months Ended		12 Months Ended
		Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) branch	Dec. 31, 2021 USD ($) branch
Restructuring Cost and Reserve [Line Items]
Gain on sale of branch disposal group, net				$ 0	$ 113	$ 0
Loans held for sale	[1]			$ 339	354
Consumer loans
Restructuring Cost and Reserve [Line Items]
Reduction to the provision for credit losses		$ 22
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Retail Branches Sold
Restructuring Cost and Reserve [Line Items]
Gain on sale of branch disposal group, net					113
Loans held for sale					2,148
Properties and equipment held for sale					45
Cash held for sale					16
Deposits held for sale					6,919
Lease liabilities held for sale					145
Other liabilities held for sale					$ 6
Exit of Mass Market Retail Banking Business
Restructuring Cost and Reserve [Line Items]
Number of branches sold | branch						90
Reduction to the provision for credit losses			$ 101
Exit of Mass Market Retail Banking Business | Consumer loans
Restructuring Cost and Reserve [Line Items]
Reduction to the provision for credit losses			$ 100
Rebranding of Retail Branches
Restructuring Cost and Reserve [Line Items]
Number of branches rebranded | branch					22

[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