Derivative Instruments - Credit Derivatives, Protection Sold, Notional and Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
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	$ (138,396)	$ (161,340)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from 1-5 years	(418,380)	(521,673)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than 5 years	(112,181)	(55,451)
Total notional amount	(668,957)	(738,464)
Fair value of receivables	9,834	10,439
Fair value of payables	(5,695)	(8,451)
Net fair value	4,139	1,988
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	(99,793)	(115,443)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from 1-5 years	(320,772)	(402,325)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than 5 years	(84,703)	(43,611)
Total notional amount	(505,268)	(561,379)
Fair value of receivables	5,166	5,720
Fair value of payables	(1,473)	(2,791)
Net fair value	3,693	2,929
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	(38,603)	(45,897)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - from 1-5 years	(97,608)	(119,348)
Protection sold credit derivatives and credit-related notes ratings/maturity profile - more than 5 years	(27,478)	(11,840)
Total notional amount	(163,689)	(177,085)
Fair value of receivables	4,668	4,719
Fair value of payables	(4,222)	(5,660)
Net fair value	$ 446	$ (941)