Offsetting Arrangements - Assets With Enforceable Netting Arrangements (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Offsetting [Abstract]
Derivative, net amount of assets presented in statement of condition	$ 5,813	$ 4,777
Derivatives, counterparty netting	0	0
Derivatives, collateral received	(403)	(405)
Derivatives, net amount	5,410	4,372
Resale agreements and securities borrowing, resale agreements and securities borrowing, net amount of assets presented in statement of condition	25,464	23,525
Resale agreements and securities borrowing, counterparty netting	(92)	(63)
Resale agreements and securities borrowing, collateral received	(24,882)	(22,812)
Resale agreements and securities borrowing, net amount	490	650
Total, net amounts of assets presented in statement of condition	31,277	28,302
Total, counterparty netting	(92)	(63)
Total, collateral received	(25,285)	(23,217)
Total, net amount	$ 5,900	$ 5,022