Derivative Instruments - Credit Derivatives, Protection Sold, Notional and Fair Value (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Protection sold credit derivatives and credit related notes ratings/maturity profile
Protection sold credit derivatives and credit related notes ratings/maturity profile - less than 1 year	$ (184,526)	$ (232,680)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from 1-5 years	(505,729)	(453,851)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than 5 years	(59,840)	(57,868)
Total notional amount	(750,095)	(744,399)
Fair value of receivables	13,756	15,923
Fair value of payables	(6,361)	(6,447)
Net fair value	7,395	9,476
Investment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Protection sold credit derivatives and credit related notes ratings/maturity profile - less than 1 year	(124,866)	(159,286)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from 1-5 years	(359,780)	(319,726)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than 5 years	(43,198)	(39,429)
Total notional amount	(527,844)	(518,441)
Fair value of receivables	6,831	8,516
Fair value of payables	(1,926)	(1,134)
Net fair value	4,905	7,382
Noninvestment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Protection sold credit derivatives and credit related notes ratings/maturity profile - less than 1 year	(59,660)	(73,394)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from 1-5 years	(145,949)	(134,125)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than 5 years	(16,642)	(18,439)
Total notional amount	(222,251)	(225,958)
Fair value of receivables	6,925	7,407
Fair value of payables	(4,435)	(5,313)
Net fair value	$ 2,490	$ 2,094