Collateralized Agreements and Financings - Other Secured Financings (Parenthetical) (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Other Secured Financings [Line Items]
Nonrecourse obligations included in other secured financings	$ 13,030	$ 10,910
Transfers of financial assets accounted for as financings included in other secured financings	2,030	2,160
Financial assets collateralizing other secured financings related to failed sales	2,040	2,210
Other secured financings collateralized by financial instruments owned	10,700	9,090
Other secured financings collateralized by financial instruments received as collateral and repledged	$ 4,690	$ 2,930
U.S. Dollar [Member]
Other Secured Financings [Line Items]
Weighted average interest rates	1.13%	2.79%
Weighted average interest rates		4.32%