Loans - Components of Loans (Details) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	[1]	$ 58,987	$ 59,380
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		39,957	41,817
Commercial loans | Real estate, including construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		7,087	7,963
Commercial loans | Business and corporate banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		15,724	16,075
Commercial loans | Global banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		10,725	10,578
Commercial loans | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		6,421	7,201
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		19,030	17,563
Consumer loans | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		18,341	16,838
Consumer loans | Home equity mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		389	370
Consumer loans | Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		199	213
Consumer loans | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		101	142
Consumer loans | Student loans held for investment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, designated under fair value option		15	20
Affiliates | Commercial loans | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		2,618	3,557
Other | Commercial loans | Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		$ 3,803	$ 3,644

[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