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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
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]	$ (1,113)	$ (213)	$ 1,161	$ (1,392)
Investment Segment | 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]	(1,697)	(150)	(229)	(1,251)
Investment Segment | 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]	584	(68)	1,390	(132)
Investment Segment | 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]		5		(9)
Energy Segment | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedging instruments recognized in income		$ 20	$ 4	$ 65	$ 20	[1]

[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.