Derivatives (Derivatives Pertaining to Hedged Items) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	$ (6)	$ (3)	$ (18)	$ (29)
Amount of Gains (Losses) Deferred in AOCI	(185)	160	235	201
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	(3)	(3)	(12)	(6)
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	(3)	0	(6)	(23)
Amount of Gains (Losses) Deferred in AOCI	(185)	160	235	201
Net Derivative Gains (Losses) Recognized for Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1,851)	1,060	2,410	(68)
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	(1,861)	1,060	2,396	(115)
Net Derivative Gains (Losses) Recognized for Derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	10	0	14	47
Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	9	10	31	28
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	9	10	31	28
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	(1)	51	92	51
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	(435)	1,657	4,321	2,906
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	0	0	1	28
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	1	1	2	2
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	(3)	(3)	(12)	(6)
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	(3)	0	(6)	(23)
Amount of Gains (Losses) Deferred in AOCI	(184)	109	143	150
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	(50)	49	57	71
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	10	0	13	19
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	9	29	26
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) 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	2	1	32
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
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) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(752)	(18)	(393)	(1,808)
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
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) Recognized for Derivatives | Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(628)	(630)	(1,590)	(1,316)
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