Pledged Assets, Accepted Collateral and Restricted Assets - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Financial Instruments Owned and Pledged as Collateral [Line Items]
Cash, held in foreign currency	$ 722,200,000	$ 330,400,000
Restricted cash	575,200,000	574,200,000
Average deposits maintained to meet Federal Reserve Bank reserve requirements	0	0
Debt Securities And Loans
Financial Instruments Owned and Pledged as Collateral [Line Items]
Collateral that may be repledged or sold	$ 1,100,000,000	$ 453,900,000