Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Summary of Pledged Assets Included in Consolidated Balance Sheet (Detail) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Interest bearing deposits with banks		$ 4,816	$ 2,682
Trading assets	[1]	6,633	525
Securities available-for-sale	[2]	14,986	6,814
Securities held to maturity	[2]	1,573	1,688
Loans	[3]	13,316	14,342
Other assets	[4]	6,634	3,517
Total		$ 47,958	$ 29,568

[1] Trading assets are primarily pledged against liabilities associated with repurchase agreements.

[2] Securities are primarily pledged against derivatives, public fund deposits, trust deposits and various short-term and long term borrowings, as well as providing capacity for potential secured borrowings from the FHLB and the Federal Reserve Bank of New York.

[3] Loans are primarily residential mortgage loans pledged against current and potential borrowings from the FHLB and the Federal Reserve Bank of New York.

[4] Other assets represent cash on deposit with non-banks related to derivative collateral support agreements.