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	$ (5)	$ (2)	$ (17)	$ (29)
Amount of Gains (Losses) Deferred in AOCI	(183)	157	231	196
Derivatives Not Designated or Not Qualifying as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivative Gains (Losses) Recognized for Hedged Items	(2)	(2)	(11)	(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	(183)	157	231	196
Net Derivative Gains (Losses) Recognized for Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1,865)	986	2,244	(189)
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	(1,873)	986	2,231	(237)
Net Derivative Gains (Losses) Recognized for Derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	8	0	13	48
Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	9	10	30	27
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	30	27
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)	1,656	4,321	2,905
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	(2)	(2)	(11)	(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	(182)	106	139	145
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	(49)	49	56	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	8	0	12	20
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	28	25
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	3	2	1	31
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	(751)	(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	(641)	(703)	(1,754)	(1,436)
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