Derivative Financial Instrument - Effect of derivative qualified as hedge accounting (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	$ (85)	$ (168)	$ (233)	$ (348)
Interest rate contracts | Other net realized capital gains/(losses) | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	4	(79)	(33)	(131)
Interest rate contracts | Other Comprehensive Income (Loss) | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income	0	1	2	2
Interest rate contracts | Net Investment Income | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income	0	0	0	0
Foreign exchange contracts | Other net realized capital gains/(losses) | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	(1)	2	6	4
Foreign exchange contracts | Other net realized capital gains/(losses) | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	0	0	0	0
Foreign exchange contracts | Other Comprehensive Income (Loss) | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income	(19)	20	73	10
Foreign exchange contracts | Net Investment Income | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	3	3	6	6
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income	3	3	6	6
Equity contracts | Other net realized capital gains/(losses) | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	(9)	(4)	(9)	(21)
Fixed maturities | Other net realized capital gains/(losses)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	(1)	2	7	3
Within products | Other net realized capital gains/(losses)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	36	(26)	(131)	(84)
Embedded derivative on reinsurance | Policyholder Benefits
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	(125)	(63)	(60)	(122)
Managed custody guarantees | Other net realized capital gains/(losses)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	9	0	(17)	0
Credit contracts | Other net realized capital gains/(losses) | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	2	0	4	3
Discontinued Operations, Held-for-sale
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	3	78	(2)	80
Discontinued Operations, Held-for-sale | Foreign exchange contracts | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	0	0	1	0
Discontinued Operations, Held-for-sale | Equity contracts | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	92	15	(61)	78
Discontinued Operations, Held-for-sale | Fixed maturities
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	0	1	2	1
Discontinued Operations, Held-for-sale | Within products
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	(89)	62	56	0
Discontinued Operations, Held-for-sale | Credit contracts | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative, net	$ 0	$ 0	$ 0	$ 1