Derivative Financial Instruments - Net Realized Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (50)	$ 48	$ (220)	$ 132
Net Investment Income	413	425	1,235	1,204
Other net realized capital gains (losses)	7	(38)	2	(198)
Other Net Realized Capital Gains (Losses) | Fixed maturities
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2	(1)	4	(5)
Other Net Realized Capital Gains (Losses) | Product
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(36)	24	(49)	56
Interest Credited and Other Benefits to Contract Owners | Reinsurance agreements
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(29)	4	(106)	53
Designated as Hedging Instrument | Other Net Realized Capital Gains (Losses) | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2	0
Designated as Hedging Instrument | Cash flow hedges | Other Net Realized Capital Gains (Losses) | Interest rate contracts
Derivatives, Fair Value [Line Items]
Net realized gains (losses) on derivatives	0		0
Designated as Hedging Instrument | Cash flow hedges | Other Net Realized Capital Gains (Losses) | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Net realized gains (losses) on derivatives	0		0
Designated as Hedging Instrument | Cash flow hedges | Other Comprehensive Income (Loss) | Interest rate contracts
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0		2
Designated as Hedging Instrument | Cash flow hedges | Other Comprehensive Income (Loss) | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	28		36
Designated as Hedging Instrument | Cash flow hedges | Net Investment Income | Interest rate contracts
Derivatives, Fair Value [Line Items]
Net realized gains (losses) on derivatives			0
Designated as Hedging Instrument | Cash flow hedges | Net Investment Income | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Net realized gains (losses) on derivatives			7
Designated as Hedging Instrument | Cash flow hedges | Investment Income | Interest rate contracts
Derivatives, Fair Value [Line Items]
Net realized gains (losses) on derivatives	0		0
Designated as Hedging Instrument | Cash flow hedges | Investment Income | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Net realized gains (losses) on derivatives	2		7
Not Designated as Hedging Instrument | Other Net Realized Capital Gains (Losses) | Credit contracts
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	2	2	2
Not Designated as Hedging Instrument | Other Net Realized Capital Gains (Losses) | Interest rate contracts
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	10	19	(76)	26
Not Designated as Hedging Instrument | Other Net Realized Capital Gains (Losses) | Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net			4	0
Not Designated as Hedging Instrument | Other Net Realized Capital Gains (Losses) | Equity contract
Derivatives, Fair Value [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ 0	$ 1	$ 0