Derivative Instruments - Credit Derivatives (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Total credit derivatives and credit-related notes
Protection sold	$ (785,141)	$ (744,399)
Protection purchased with identical underlyings	800,282	761,256
Net protection (sold)/purchased	15,141	16,857
Other protection purchased	25,557	24,707
Total credit derivatives
Total credit derivatives and credit-related notes
Protection sold	(785,123)	(744,381)
Protection purchased with identical underlyings	800,282	761,256
Net protection (sold)/purchased	15,159	16,875
Other protection purchased	17,904	16,792
Credit default swaps
Total credit derivatives and credit-related notes
Protection sold	(746,195)	(690,224)
Protection purchased with identical underlyings	754,889	702,098
Net protection (sold)/purchased	8,694	11,874
Other protection purchased	6,341	5,045
Other credit derivatives
Total credit derivatives and credit-related notes
Protection sold	(38,928)	(54,157)
Protection purchased with identical underlyings	45,393	59,158
Net protection (sold)/purchased	6,465	5,001
Other protection purchased	11,563	11,747
Credit-related notes
Total credit derivatives and credit-related notes
Protection sold	(18)	(18)
Protection purchased with identical underlyings	0	0
Net protection (sold)/purchased	(18)	(18)
Other protection purchased	$ 7,653	$ 7,915