Loans Held for Sale - Additional Information (Details) - USD ($)		3 Months Ended			6 Months Ended	12 Months Ended
		Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	[1]	$ 4,217,000,000			$ 4,217,000,000	$ 4,217,000,000	$ 337,000,000
Loans, designated under fair value option		0			0	0	32,000,000
Loans	[1]	55,864,000,000			55,864,000,000	55,864,000,000	62,088,000,000
Revenue (losses) associated with the economic hedging program						1,055,000,000	824,000,000	$ 2,082,000,000
Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lower of amortized cost or fair value adjustment				$ 0
Commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		461,000,000			461,000,000	461,000,000	129,000,000
Loans		39,796,000,000			39,796,000,000	39,796,000,000	41,599,000,000
Valuation allowance		5,000,000			5,000,000	5,000,000	1,000,000
Commercial loans: | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		79,000,000		149,000,000	79,000,000	79,000,000
Lower of amortized cost or fair value adjustment				0
Consumer loans held for sale | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		778,000,000			778,000,000	778,000,000
Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		3,756,000,000			3,756,000,000	3,756,000,000	208,000,000
Loans		16,068,000,000			16,068,000,000	16,068,000,000	20,489,000,000
Valuation allowance		7,000,000			7,000,000	7,000,000	0
Consumer loans: | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		3,681,000,000		3,616,000,000	3,681,000,000	3,681,000,000
Lower of amortized cost or fair value adjustment				0	7,000,000
Commercial Loans - Transferred to Held for Sale | Commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		359,000,000			359,000,000	359,000,000	93,000,000
Commercial Real Estate Loans - Transferred to Held for Sale | Commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lower of amortized cost or fair value adjustment			$ 0
Sales of loans held for sale		1,032,000,000
Gain on sale of loans		0
Commercial Loans - Fair Value Option | Commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		23,000,000			23,000,000	23,000,000	36,000,000
Residential mortgages | Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		3,082,000,000			3,082,000,000	3,082,000,000	208,000,000
Loans		15,469,000,000			15,469,000,000	15,469,000,000	18,377,000,000
Residential mortgages | Consumer loans: | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		3,007,000,000		2,364,000,000	3,007,000,000	3,007,000,000
Home Equity Mortgages | Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		275,000,000			275,000,000	275,000,000	0
Home Equity Mortgages | Consumer loans: | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		275,000,000		265,000,000	275,000,000	275,000,000
Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale				1,100,000,000
Credit cards | Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		195,000,000			195,000,000	195,000,000	0
Loans		204,000,000			204,000,000	204,000,000	1,066,000,000
Credit cards | Consumer loans: | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		195,000,000		829,000,000	195,000,000	195,000,000
Sales of loans held for sale		382,000,000
Gain on sale of loans		$ 9,000,000
Credit cards | Consumer loans: | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period of loan servicing after sale		1 year
Student Loans | Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, designated under fair value option		$ 25,000,000			25,000,000	25,000,000	32,000,000
Other consumer | Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		204,000,000			204,000,000	204,000,000	0
Loans		70,000,000			70,000,000	70,000,000	319,000,000
Other consumer | Consumer loans: | Exit of Mass Market Retail Banking Business and Remaining Retail Credit Card Portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale		$ 204,000,000		$ 158,000,000	$ 204,000,000	204,000,000
Other income (loss) | Commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lower of amortized cost or fair value adjustment						7,000,000	23,000,000	0
Residential mortgage banking revenue (expense)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Revenue (losses) associated with the economic hedging program						$ (2,000,000)	$ (6,000,000)	$ (1,000,000)

[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