Financial Instruments Gain (Loss) Recognized on Derivatives Not Designated as Hedging Table (Details) - Not designated as hedging instrument - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]			$ (1,372)	$ 78
Equity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]			(1,251)	(89)
Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]			(132)	53
Commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]			11	114
Net gain from investment activities
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]	$ (209)	$ (128)
Net gain from investment activities | Equity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]	(150)	(147)
Net gain from investment activities | Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]	(68)	0
Net gain from investment activities | Commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]	9	19
Investment Segment | Net gain from investment activities
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]	(213)	(139)	(1,392)	8
Energy Segment | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income	[1]	$ 4	$ 11	$ 20	$ 70

[1] Gains (losses) recognized on derivatives are classified in net gain (loss) from investment activities in our condensed consolidated statements of operations for our Investment segment and are included in cost of goods sold for our Energy segment. (Losses) gains recognized on derivatives for our Investment segment were $(213) million and $(139) million for the three months ended June 30, 2019 and 2018, respectively, and $(1,392) million and $8 million for the six months ended June 30, 2019 and 2018, respectively. Gains recognized on derivatives for our Energy segment were $4 million and $11 million for the three months ended June 30, 2019 and 2018, respectively, and $20 million and $70 million for the six months ended June 30, 2019 and 2018, respectively.