Financial Instruments Gain (Loss) Recognized on Derivatives Not Designated as Hedging Table (Details) - Investment Segment - Net gain (loss) from investment activities - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative gain (loss) recognized in income	$ (2,502)	$ 798	$ (1,969)
Equity Contract [Member]
Derivative [Line Items]
Derivative gain (loss) recognized in income	(2,152)	603	(1,815)
Credit Risk Contract [Member]
Derivative [Line Items]
Derivative gain (loss) recognized in income	(342)	129	(42)
Commodity Contract [Member]
Derivative [Line Items]
Derivative gain (loss) recognized in income	$ (8)	$ 66	$ (112)