Derivatives - Derivative Balance Sheet Classification (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 13,706	$ 12,291
Fair Value	(66)	(61)
Asset Derivatives	40	31
Liability Derivatives	(106)	(92)
Fixed maturities, available-for-sale
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	244	153
Fair Value	0	0
Asset Derivatives	0	0
Liability Derivatives	0	0
Other investments
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,277	9,864
Fair Value	12	7
Asset Derivatives	13	23
Liability Derivatives	(1)	(16)
Other liabilities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	12,185	2,274
Fair Value	(78)	(68)
Asset Derivatives	27	8
Liability Derivatives	(105)	(76)
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,310	2,193
Fair Value	(1)	(5)
Asset Derivatives	4	4
Liability Derivatives	(5)	(9)
Designated as Hedging Instrument \| Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,040	2,040
Fair Value	0	1
Asset Derivatives	1	2
Liability Derivatives	(1)	(1)
Designated as Hedging Instrument \| Foreign currency swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	270	153
Fair Value	(1)	(6)
Asset Derivatives	3	2
Liability Derivatives	(4)	(8)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	11,396	10,098
Fair Value	(65)	(56)
Asset Derivatives	36	27
Liability Derivatives	(101)	(83)
Not Designated as Hedging Instrument \| Interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	7,600	7,100
Not Designated as Hedging Instrument \| Interest rate swaps and futures
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	9,338	8,451
Fair Value	(59)	(62)
Asset Derivatives	3	8
Liability Derivatives	(62)	(70)
Not Designated as Hedging Instrument \| Foreign currency swaps and forwards
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	464	287
Fair Value	(1)	(1)
Asset Derivatives	0	0
Liability Derivatives	(1)	(1)
Not Designated as Hedging Instrument \| Credit derivatives that purchase credit protection
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	124	6
Fair Value	(3)	0
Asset Derivatives	0	0
Liability Derivatives	(3)	0
Not Designated as Hedging Instrument \| Credit derivatives that assume credit risk
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	500	1,102
Fair Value	13	3
Asset Derivatives	13	8
Liability Derivatives	0	(5)
Not Designated as Hedging Instrument \| Credit derivatives in offsetting positions
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	29	41
Fair Value	0	0
Asset Derivatives	5	6
Liability Derivatives	(5)	(6)
Not Designated as Hedging Instrument \| Equity index swaps and options
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	941	211
Fair Value	(15)	4
Asset Derivatives	15	5
Liability Derivatives	$ (30)	$ (1)

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Nominal or face amount used to calculate payment on derivative.

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