Derivatives Derivatives (Derivatives Pertaining to Hedged Items) (Details) - 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]
Net Derivative Gains (Losses) Recognized for Hedged Items	$ (27)	$ (2)	$ (27)	$ 8
Amount of Gains (Losses) deferred in AOCI	73	108	39	35
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	(4)	(5)	(4)	(2)
Amount of Gains (Losses) deferred in AOCI	0	0	0	0
Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	(23)	0	(23)	0
Amount of Gains (Losses) deferred in AOCI	73	108	39	35
Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items		3		10
Amount of Gains (Losses) deferred in AOCI		0		0
Net derivative gains (losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	135	(276)	(1,175)	(573)
Net derivative gains (losses) | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	112	(283)	(1,223)	(579)
Net derivative gains (losses) | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	23	9	48	16
Net derivative gains (losses) | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		(2)		(10)
Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	8	9	17	15
Net Investment Income | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Net Investment Income | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	8	9	17	15
Net Investment Income | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		0		0
Policyholder benefits and claims
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(1)	0	(2)
Policyholder benefits and claims | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(1)	0	(2)
Policyholder benefits and claims | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder benefits and claims | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		0		0
Interest rate derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0	0	0
Amount of Gains (Losses) deferred in AOCI	0	0	0	0
Interest rate derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0	0	0
Amount of Gains (Losses) deferred in AOCI	0	0	0	(2)
Interest rate derivatives | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items		3		10
Amount of Gains (Losses) deferred in AOCI		0		0
Interest rate derivatives | Net derivative gains (losses) | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	917	(151)	1,249	(924)
Interest rate derivatives | Net derivative gains (losses) | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	6	10	28	17
Interest rate derivatives | Net derivative gains (losses) | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		(2)		(10)
Interest rate derivatives | Net Investment Income | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Interest rate derivatives | Net Investment Income | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	2	1	4
Interest rate derivatives | Net Investment Income | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		0		0
Interest rate derivatives | Policyholder benefits and claims | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Interest rate derivatives | Policyholder benefits and claims | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Interest rate derivatives | Policyholder benefits and claims | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net		0		0
Foreign currency exchange rate derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	(4)	(5)	(4)	(2)
Amount of Gains (Losses) deferred in AOCI	0	0	0	0
Foreign currency exchange rate derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	(23)	0	(23)	0
Amount of Gains (Losses) deferred in AOCI	73	108	39	37
Foreign currency exchange rate derivatives | Net derivative gains (losses) | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	30	60	22	23
Foreign currency exchange rate derivatives | Net derivative gains (losses) | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	17	(1)	20	(1)
Foreign currency exchange rate derivatives | Net Investment Income | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Foreign currency exchange rate derivatives | Net Investment Income | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	8	7	16	11
Foreign currency exchange rate derivatives | Policyholder benefits and claims | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Foreign currency exchange rate derivatives | Policyholder benefits and claims | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Credit derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0	0	0
Amount of Gains (Losses) deferred in AOCI	0	0	0	0
Credit derivatives | Net derivative gains (losses) | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	11	0	29	(4)
Credit derivatives | Net Investment Income | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Credit derivatives | Policyholder benefits and claims | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Equity derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0	0	0
Amount of Gains (Losses) deferred in AOCI	0	0	0	0
Equity derivatives | Net derivative gains (losses) | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(344)	(424)	(1,790)	(458)
Equity derivatives | Net Investment Income | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Equity derivatives | Policyholder benefits and claims | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Embedded derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0	0	0
Amount of Gains (Losses) deferred in AOCI	0	0	0	0
Embedded derivatives | Net derivative gains (losses) | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(502)	232	(733)	784
Embedded derivatives | Net Investment Income | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Embedded derivatives | Policyholder benefits and claims | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ (1)	$ 0	$ (2)