Loans and Allowance for Credit Losses - Net Loans (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	$ 44,685	$ 43,200
Allowance for credit losses	(176)	(174)
Loans, net of allowance	44,509	43,026
Commercial and financial | Securities Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,480	3,010
Commercial and financial | Municipal Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	214	214
Commercial and financial | Floating Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	38,900
Commercial and financial | Fixed Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,760
Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	26,286	26,409
Domestic | Commercial and financial | Fund Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	16,413	16,347
Domestic | Commercial and financial | Leveraged Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,795	2,742
Domestic | Commercial and financial | Overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	1,596	1,208
Domestic | Commercial and financial | Collateralized Loan Obligations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	95	50
Domestic | Commercial and financial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,691	3,220
Domestic | Commercial and financial | Private Equity Capital Call Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	11,780	11,540
Domestic | Commercial and financial | Real Money Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	7,840	8,090
Domestic | Commercial and financial | Business Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	1,500	1,440
Domestic | Commercial real estate | Commercial Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,696	2,842
Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	18,399	16,791
Non-U.S. | Commercial and financial | Fund Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	6,736	6,601
Non-U.S. | Commercial and financial | Leveraged Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	1,069	1,082
Non-U.S. | Commercial and financial | Overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	1,424	772
Non-U.S. | Commercial and financial | Collateralized Loan Obligations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	$ 9,170	$ 8,336