Derivative Instruments - Summary of Notional and Fair Value of Derivative Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Funds withheld liability (portion at fair value: 2021 – $34 and 2020 – $59)	$ 422	$ 452
Derivative assets, fair value	3,677	3,523
Derivative liabilities, fair value	288	298
Total derivative assets	4,893	6,329
Total derivative liabilities	12,795	13,230
Derivatives designated as hedges
Derivative [Line Items]
Derivative assets, fair value	179	137
Derivative liabilities, fair value	$ 247	$ 192
Derivatives designated as hedges \| Foreign currency swaps
Derivative [Line Items]
Notional Amount	4,856	4,417
Derivative assets, fair value	$ 120	$ 134
Derivative liabilities, fair value	$ 183	$ 181
Derivatives designated as hedges \| Foreign currency forwards
Derivative [Line Items]
Notional Amount	3,465	2,038
Derivative assets, fair value	$ 58	$ 3
Derivative liabilities, fair value	$ 7	$ 9
Derivatives designated as hedges \| Cross Currency Interest Rate Contract
Derivative [Line Items]
Notional Amount	1,183	0
Derivative assets, fair value	$ 1	$ 0
Derivative liabilities, fair value	57	0
Derivatives not designated as hedges
Derivative [Line Items]
Total derivative assets	4,714	6,192
Total derivative liabilities	$ 12,548	$ 13,038
Derivatives not designated as hedges \| Foreign currency swaps
Derivative [Line Items]
Notional Amount	1,541	1,510
Derivative assets, fair value	$ 53	$ 96
Derivative liabilities, fair value	$ 0	$ 0
Derivatives not designated as hedges \| Interest rate swaps
Derivative [Line Items]
Notional Amount	805	803
Derivative assets, fair value	$ 27	$ 0
Derivative liabilities, fair value	$ 3	$ 34
Derivatives not designated as hedges \| Equity options
Derivative [Line Items]
Notional Amount	54,116	53,666
Derivative assets, fair value	$ 3,297	$ 3,209
Derivative liabilities, fair value	$ 17	$ 22
Derivatives not designated as hedges \| Futures
Derivative [Line Items]
Notional Amount	26	24
Derivative assets, fair value	$ 40	$ 58
Derivative liabilities, fair value	$ 0	$ 2
Derivatives not designated as hedges \| Total return swaps
Derivative [Line Items]
Notional Amount	119	97
Derivative assets, fair value	$ 4	$ 6
Derivative liabilities, fair value	$ 0	$ 0
Derivatives not designated as hedges \| Credit default swaps
Derivative [Line Items]
Notional Amount	10	10
Derivative assets, fair value	$ 0	$ 0
Derivative liabilities, fair value	$ 5	$ 4
Derivatives not designated as hedges \| Foreign currency forwards
Derivative [Line Items]
Notional Amount	4,686	3,595
Derivative assets, fair value	$ 77	$ 17
Derivative liabilities, fair value	16	44
Derivatives not designated as hedges \| Embedded derivatives \| Funds withheld
Derivative [Line Items]
Funds withheld at interest	1,216
Funds withheld liability (portion at fair value: 2021 – $34 and 2020 – $59)	34
Embedded derivative assets, fair value		2,806
Embedded derivative liabilities, fair value		59
Derivatives not designated as hedges \| Embedded derivatives \| Interest sensitive contract liabilities
Derivative [Line Items]
Embedded derivative assets, fair value	0	0
Embedded derivative liabilities, fair value	$ 12,473	$ 12,873
Net Investment Hedging [Member] \| Derivatives designated as hedges \| Foreign currency forwards
Derivative [Line Items]
Notional Amount	224	173
Derivative assets, fair value	$ 0	$ 0
Derivative liabilities, fair value	$ 0	$ 2

Fair value, after the 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 not subject to a master netting arrangement and not elected to be offset.

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Amount of the reinsurer's funds held on its behalf by the ceding insurer, including funds held in trust, under reinsurance treaties or contracts with the assuming insurer as security for the payment of the obligations thereunder.

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