Offsetting Arrangements - Liabilities With Offsetting Arrangements (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	$ 13,792	$ 16,684
Derivatives, Gross amounts offset in statement of condition	(7,340)	(10,682)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	6,452	6,002
Derivative, Net Amount	6,134	5,822
Derivatives, Cash and collateral securities netting, offset	(1,193)	(2,356)
Derivatives, Cash and collateral securities netting, Cash and Securities Provided	(318)	(180)
Derivatives, Cash and collateral securities netting, Net	(1,511)	(2,536)
Resale agreements and securities lending, Gross Amounts of Recognized Liabilities(1)(2)	43,168	44,933
Resale agreements and securities lending, Gross Amounts Offset in Statement of Condition(3)	(34,997)	(35,517)
Resale agreements and securities lending, Net Amounts of Liabilities Presented in Statement of Condition	8,171	9,416
Resale agreements and securities lending, Cash and Securities Provided	(5,844)	(7,059)
Resale agreements and securities lending, Net Amount	2,327	2,357
Total derivatives and other financial instruments, Gross Amounts of Recognized Liabilities	56,960	61,617
Total derivatives and other financial instruments, Gross Amounts Offset in Statement of Condition	(42,337)	(46,199)
Total derivatives and other financial instruments, Net Amounts of Liabilities Presented in Statement of Condition	14,623	15,418
Total derivatives and other financial instruments, Cash and Securities Provided	(6,162)	(7,239)
Total derivatives and other financial instruments, Net Amount	8,461	8,179
Securities sold under repurchase agreements	3,856	4,400
Securities lending, fair value, amount not offset against collateral	4,315	5,016
Foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	13,312	15,956
Derivatives, Gross amounts offset in statement of condition	(6,145)	(8,253)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	7,167	7,703
Derivative, Net Amount	7,167	7,703
Interest-rate contracts(6)
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	124	348
Derivatives, Gross amounts offset in statement of condition	(2)	(73)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	122	275
Derivative, Net Amount	122	275
Other derivative contracts
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	356	380
Derivatives, Gross amounts offset in statement of condition	0	0
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	356	380
Derivative, Net Amount	$ 356	$ 380