Loans - Components of Loans (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	[1]	$ 55,864	$ 62,088
Loans, designated under fair value option		0	32
Commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		39,796	41,599
Commercial loans: | Real Estate, including Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		8,234	10,464
Commercial loans: | Business and corporate banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		13,958	13,479
Loans funded under the Payroll Protection Program		262	1,043
Commercial loans: | Global banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		11,109	13,519
Commercial loans: | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		6,495	4,137
Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		16,068	20,489
Consumer loans: | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		15,469	18,377
Consumer loans: | Home equity mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		325	727
Consumer loans: | Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		204	1,066
Consumer loans: | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		70	319
Consumer loans: | Student Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, designated under fair value option		25	32
Affiliated Entity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,793	1,100
Affiliated Entity | Commercial loans: | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,793	1,100
Other [Member] | Commercial loans: | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 3,702	$ 3,037

[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