Restricted Cash and Other Restricted Assets (Details) - USD ($) $ in Billions	Mar. 31, 2022	Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	$ 30.8	$ 19.7
Cash and securities pledged with clearing organizations for the benefit of customers	41.5	47.5
Fair value of securities restricted in relation to customer activity	34.4	30.0
Deposits with banks
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	29.6	18.4
Cash and due from banks
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	1.2	1.3
Segregated for the benefit of securities and cleared derivative customers
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	23.4	14.6
Cash reserves at non-U.S. central banks and held for other general purposes
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash	$ 7.4	$ 5.1