Offsetting Arrangements - Assets With Offsetting Arrangements (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Offsetting Assets [Line Items]
Derivatives, gross amounts of recognized assets	$ 21,380	$ 11,456
Derivatives, gross amounts offset in statement of condition	(12,596)	(6,679)
Net Amounts of Assets Presented in Statement of Condition	8,784	4,777
Derivative, collateral, cash offset	(1,966)	(776)
Resale agreements and securities borrowing, gross amounts of recognized assets	60,336	62,522
Resale agreements and securities borrowing, gross amounts offset in statement of condition	(38,251)	(38,997)
Net Amounts of Assets Presented in Statement of Condition	22,085	23,525
Total, gross amounts of recognized assets	81,716	73,978
Total, gross amounts offset in statement of condition	(50,847)	(45,676)
Total, net amounts of assets presented in statement of condition	30,869	28,302
Securities purchased under resale agreements	2,010	3,404
Securities borrowed subject to master netting arrangements	20,075	20,121
Foreign exchange contracts
Offsetting Assets [Line Items]
Derivatives, gross amounts of recognized assets	20,868	11,316
Derivatives, gross amounts offset in statement of condition	(10,615)	(5,896)
Net Amounts of Assets Presented in Statement of Condition	10,253	5,420
Interest-rate contracts
Offsetting Assets [Line Items]
Derivatives, gross amounts of recognized assets	507	135
Derivatives, gross amounts offset in statement of condition	(10)	(5)
Net Amounts of Assets Presented in Statement of Condition	497	130
Other derivative contracts
Offsetting Assets [Line Items]
Derivatives, gross amounts of recognized assets	5	5
Derivatives, gross amounts offset in statement of condition	(5)	(2)
Net Amounts of Assets Presented in Statement of Condition	$ 0	$ 3