Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Summary of Pledged Assets Included in Consolidated Balance Sheet (Detail) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Interest bearing deposits with banks		$ 3,225	$ 2,952
Trading assets	[1]	2,465	3,185
Securities available-for-sale	[2]	7,440	7,210
Securities held to maturity	[2]	1,747	2,131
Loans	[3]	18,189	17,404
Other assets	[4]	2,289	2,253
Total		$ 35,355	$ 35,135

[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.