Business Segments Additional Information (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Loans held for sale (includes $48 million and $36 million designated under fair value option at December 31, 2021 and 2020, respectively, and $2,441 million related to branch disposal group held for sale at December 31, 2021)	[1]		$ 4,217	$ 337
Credit cards
Segment Reporting Information [Line Items]
Loans held for sale (includes $48 million and $36 million designated under fair value option at December 31, 2021 and 2020, respectively, and $2,441 million related to branch disposal group held for sale at December 31, 2021)		$ 1,100
Consumer loans:
Segment Reporting Information [Line Items]
Loans held for sale (includes $48 million and $36 million designated under fair value option at December 31, 2021 and 2020, respectively, and $2,441 million related to branch disposal group held for sale at December 31, 2021)			3,756	208
Consumer loans: | Credit cards
Segment Reporting Information [Line Items]
Loans held for sale (includes $48 million and $36 million designated under fair value option at December 31, 2021 and 2020, respectively, and $2,441 million related to branch disposal group held for sale at December 31, 2021)			195	0
Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio | Consumer loans:
Segment Reporting Information [Line Items]
Loans held for sale (includes $48 million and $36 million designated under fair value option at December 31, 2021 and 2020, respectively, and $2,441 million related to branch disposal group held for sale at December 31, 2021)		3,616	3,681
Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio | Consumer loans: | Credit cards
Segment Reporting Information [Line Items]
Loans held for sale (includes $48 million and $36 million designated under fair value option at December 31, 2021 and 2020, respectively, and $2,441 million related to branch disposal group held for sale at December 31, 2021)		829	195
Occupancy Expense, Net | Write Down of Leasehold Improvement Assets
Segment Reporting Information [Line Items]
Fixed asset impairment charges		$ 18	$ 18	$ 16

[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