Offsetting Arrangements - Liabilities With Offsetting Arrangements (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	$ 11,597	$ 16,807
Derivatives, Gross amounts offset in statement of condition	(7,519)	(11,564)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	4,078	5,243
Derivative, Net Amount	3,445	5,028
Derivative liability, collateral, cash offset	(1,192)	(1,341)
Derivatives, Cash and collateral securities netting, Cash and Securities Provided	(633)	(215)
Derivatives, Cash and collateral securities netting, Net	(1,825)	(1,556)
Resale agreements and securities lending, Gross Amounts of Recognized Liabilities(1)(2)	93,272	104,494
Resale agreements and securities lending, Gross Amounts Offset in Statement of Condition(3)	(77,842)	(91,889)
Resale agreements and securities lending, Net Amounts of Liabilities Presented in Statement of Condition	15,430	12,605
Resale agreements and securities lending, Cash and Securities Provided	(14,103)	(11,543)
Resale agreements and securities lending, Net Amount	1,327	1,062
Total derivatives and other financial instruments, Gross Amounts of Recognized Liabilities	104,869	121,301
Total derivatives and other financial instruments, Gross Amounts Offset in Statement of Condition	(85,361)	(103,453)
Total derivatives and other financial instruments, Net Amounts of Liabilities Presented in Statement of Condition	19,508	17,848
Total derivatives and other financial instruments, Cash and Securities Provided	(14,736)	(11,758)
Total derivatives and other financial instruments, Net Amount	4,772	6,090
Securities sold under repurchase agreements	1,420	1,082
Foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	11,300	16,522
Derivatives, Gross amounts offset in statement of condition	(6,327)	(10,223)
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	4,973	6,299
Derivative, Net Amount	4,973	6,299
Interest rate contracts
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	69	71
Derivatives, Gross amounts offset in statement of condition	0	0
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	69	71
Derivative, Net Amount	69	71
Other derivative contracts
Offsetting Liabilities [Line Items]
Derivatives, Gross amounts of recognized liabilities	228	214
Derivatives, Gross amounts offset in statement of condition	0	0
Derivatives, Net Amounts of Liabilities Presented in Statement of Condition	228	214
Derivative, Net Amount	$ 228	$ 214