Derivative Instruments - Credit Derivatives, Protection Sold, Notional and Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Protection sold credit derivatives and credit related notes ratings/maturity profile
Less than 1 year	$ (161,340)	$ (232,680)
From 1-5 years	(521,673)	(453,851)
More than 5 years	(55,451)	(57,868)
Total notional amount	(738,464)	(744,399)
Fair value of receivables	10,439	15,923
Fair value of payables	(8,451)	(6,447)
Net fair value	1,988	9,476
Investment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Less than 1 year	(115,443)	(159,286)
From 1-5 years	(402,325)	(319,726)
More than 5 years	(43,611)	(39,429)
Total notional amount	(561,379)	(518,441)
Fair value of receivables	5,720	8,516
Fair value of payables	(2,791)	(1,134)
Net fair value	2,929	7,382
Noninvestment-grade
Protection sold credit derivatives and credit related notes ratings/maturity profile
Less than 1 year	(45,897)	(73,394)
From 1-5 years	(119,348)	(134,125)
More than 5 years	(11,840)	(18,439)
Total notional amount	(177,085)	(225,958)
Fair value of receivables	4,719	7,407
Fair value of payables	(5,660)	(5,313)
Net fair value	$ (941)	$ 2,094