Branch Assets and Liabilities Held for Sale - Narrative (Details)		1 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended
		May 31, 2021 branch	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Revenues associated with the disposal group as percent of consolidated revenues (percent)						7.00%
Loans held for sale	[1]		$ 4,217,000,000		$ 4,217,000,000	$ 4,217,000,000	$ 337,000,000
Reduction to the provision for credit losses			22,000,000
Consumer loans:
Restructuring Cost and Reserve [Line Items]
Loans held for sale			3,756,000,000		3,756,000,000	3,756,000,000	208,000,000
Reduction to the provision for credit losses			22,000,000
Credit cards
Restructuring Cost and Reserve [Line Items]
Loans held for sale				$ 1,100,000,000
Credit cards | Consumer loans:
Restructuring Cost and Reserve [Line Items]
Loans held for sale			195,000,000		195,000,000	195,000,000	$ 0
Retail Branches Sold
Restructuring Cost and Reserve [Line Items]
Assets held for sale			2,690,000,000		2,690,000,000	2,690,000,000
Liabilities held for sale			8,902,000,000		8,902,000,000	8,902,000,000
Transaction cost						8,000,000
Loans held for sale			2,441,000,000		2,441,000,000	2,441,000,000
Retail Branches Sold | Credit cards
Restructuring Cost and Reserve [Line Items]
Loans held for sale			178,000,000		178,000,000	178,000,000
Rebranding of Retail Branches | Minimum
Restructuring Cost and Reserve [Line Items]
Number of bank branches | branch		20
Rebranding of Retail Branches | Maximum
Restructuring Cost and Reserve [Line Items]
Number of bank branches | branch		25
Exit of Mass Market Retail Banking Business
Restructuring Cost and Reserve [Line Items]
Number of branches sold | branch		90
Assets held for sale				2,900,000,000
Liabilities held for sale				10,100,000,000
Lower of amortized cost or fair value adjustment				0
Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Restructuring Cost and Reserve [Line Items]
Lower of amortized cost or fair value adjustment				0
Reduction to the provision for credit losses				101,000,000
Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio | Consumer loans:
Restructuring Cost and Reserve [Line Items]
Lower of amortized cost or fair value adjustment				0	7,000,000
Loans held for sale			3,681,000,000	3,616,000,000	3,681,000,000	3,681,000,000
Reduction to the provision for credit losses				100,000,000
Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio | Credit cards | Consumer loans:
Restructuring Cost and Reserve [Line Items]
Loans held for sale			$ 195,000,000	$ 829,000,000	$ 195,000,000	$ 195,000,000

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at December 31, 2021 and 2020. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 27, "Variable Interest Entities," for additional information. At December 31,20212020(in millions)AssetsLoans$46 $10 Other assets55 79 Total assets$101 $89 LiabilitiesInterest, taxes and other liabilities$9 $10 Total liabilities$9 $10