Derivatives Derivatives (Derivatives Pertaining to Hedged Items) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	$ (7)	$ 0
Amount of Gains (Losses) deferred in AOCI	553	(34)
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	(7)	0
Amount of Gains (Losses) deferred in AOCI	0	0
Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0
Amount of Gains (Losses) deferred in AOCI	553	(34)
Net Derivative Gains (Losses) Recognized for Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	6,754	(1,310)
Net Derivative Gains (Losses) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	6,753	(1,335)
Net Derivative Gains (Losses) Recognized for Derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	25
Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	12	9
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
Net Investment Income | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	12	9
Policyholder benefits and claims
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0
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
Policyholder benefits and claims | Cash flow 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
Amount of Gains (Losses) deferred in AOCI	0	0
Interest rate derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0
Amount of Gains (Losses) deferred in AOCI	97	0
Interest rate derivatives | Net Derivative Gains (Losses) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	4,921	332
Interest rate derivatives | Net Derivative Gains (Losses) Recognized for Derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	22
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
Interest rate derivatives | Net Investment Income | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	1
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
Interest rate derivatives | Policyholder benefits and claims | Cash flow 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	(7)	0
Amount of Gains (Losses) deferred in AOCI	0	0
Foreign currency exchange rate derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	0	0
Amount of Gains (Losses) deferred in AOCI	456	(34)
Foreign currency exchange rate derivatives | Net Derivative Gains (Losses) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	132	(8)
Foreign currency exchange rate derivatives | Net Derivative Gains (Losses) Recognized for Derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	3
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
Foreign currency exchange rate derivatives | Net Investment Income | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	11	8
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
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
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
Amount of Gains (Losses) deferred in AOCI	0	0
Credit derivatives | Net Derivative Gains (Losses) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(31)	18
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
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
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
Amount of Gains (Losses) deferred in AOCI	0	0
Equity derivatives | Net Derivative Gains (Losses) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1,964	(1,446)
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
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
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
Amount of Gains (Losses) deferred in AOCI	0	0
Embedded derivatives | Net Derivative Gains (Losses) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(233)	(231)
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
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	$ 0