Loans and Allowance for Credit Losses - Net Loans (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	$ 31,585	$ 27,925
Allowance for credit losses	(118)	(122)
Loans, net of allowance	31,467	27,803
Geographic Distribution, Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	22,723	21,132
Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	8,862	6,793
Fund Finance | Securities Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	1,110	1,911
Fund Finance | Municipal Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	831	754
Fund Finance | Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	51	54
Fund Finance | Geographic Distribution, Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	11,054	11,531
Fund Finance | Geographic Distribution, Domestic | 40 Act Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	6,288	6,391
Fund Finance | Geographic Distribution, Domestic | Private Equity Capital Call Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	8,450	8,380
Fund Finance | Geographic Distribution, Domestic | Business Development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	832	821
Fund Finance | Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	4,768	4,432
Leveraged loans | Geographic Distribution, Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	3,103	2,923
Leveraged loans | Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	1,109	1,242
Overdrafts | Geographic Distribution, Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	4,507	1,894
Overdrafts | Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,956	1,088
Other | Geographic Distribution, Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	1,963	2,688
Other | Non-U.S.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	29	31
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,096	2,096
Commercial real estate | Geographic Distribution, Domestic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	$ 2,096	$ 2,096