Collateralized Agreements and Financings - Schedule of Repurchase Agreements and Securities Loaned (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Offsetting Liabilities [Line Items]
Repurchase agreements	$ 143,597	$ 128,452
Securities loaned	15,505	$ 12,495
No Stated Maturity and Overnight [Member]
Offsetting Liabilities [Line Items]
Repurchase agreements	45,786
Securities loaned	7,010
2 - 30 Days [Member]
Offsetting Liabilities [Line Items]
Repurchase agreements	48,967
Securities loaned	3,770
31 - 90 Days [Member]
Offsetting Liabilities [Line Items]
Repurchase agreements	11,632
Securities loaned	595
91 Days - 1 Year [Member]
Offsetting Liabilities [Line Items]
Repurchase agreements	24,929
Securities loaned	3,126
Greater than 1 Year [Member]
Offsetting Liabilities [Line Items]
Repurchase agreements	12,283
Securities loaned	$ 1,004