Fair Value of Financial Instruments - Carrying Amounts of Assets and Liabilities at Estimated Fair Value Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Assets
Fixed maturity securities, available for sale	$ 25,114	$ 2,090
Derivative investments	333	0
Total financial assets at fair value	2,920
Level 1
Assets
Cash and cash equivalents	2,353	1,376
Equity securities		810
Derivative investments	1
Short term investments	209	876
Total financial assets at fair value	4,053	3,127
Liabilities
Fair value of future policy benefits	0
Derivatives:
Total financial liabilities at fair value	0
Level 2
Assets
Cash and cash equivalents	0	0
Equity securities		0
Derivative investments	332
Short term investments	0	0
Total financial assets at fair value	22,986	2,331
Liabilities
Fair value of future policy benefits	0
Derivatives:
Total financial liabilities at fair value	35
Level 3
Assets
Cash and cash equivalents	0	0
Equity securities		1
Derivative investments	0
Short term investments	0	0
Total financial assets at fair value	2,920	138
Liabilities
Fair value of future policy benefits	5
Derivatives:
Total financial liabilities at fair value	2,957
Fair Value
Assets
Cash and cash equivalents	2,353	1,376
Equity securities		811
Derivative investments	333
Short term investments	209	876
Total financial assets at fair value	29,959	5,596
Liabilities
Fair value of future policy benefits	5
Derivatives:
Total financial liabilities at fair value	2,992
Carrying Value
Assets
Cash and cash equivalents	2,353	1,376
Equity securities		811
Derivative investments	333
Short term investments	209	876
Total financial assets at fair value	29,959	5,596
Liabilities
Fair value of future policy benefits	5
Derivatives:
Total financial liabilities at fair value	2,992
FIA embedded derivatives, included in contractholder funds \| Level 1
Derivatives:
Derivative liability	0
FIA embedded derivatives, included in contractholder funds \| Level 2
Derivatives:
Derivative liability	0
FIA embedded derivatives, included in contractholder funds \| Level 3
Derivatives:
Derivative liability	2,952
FIA embedded derivatives, included in contractholder funds \| Fair Value
Derivatives:
Derivative liability	2,952
FIA embedded derivatives, included in contractholder funds \| Carrying Value
Derivatives:
Derivative liability	2,952
Reinsurance related embedded derivatives, included in accounts payable and accrued liabilities \| Level 1
Derivatives:
Derivative liability	0
Reinsurance related embedded derivatives, included in accounts payable and accrued liabilities \| Level 2
Derivatives:
Derivative liability	35
Reinsurance related embedded derivatives, included in accounts payable and accrued liabilities \| Level 3
Derivatives:
Derivative liability	0
Reinsurance related embedded derivatives, included in accounts payable and accrued liabilities \| Fair Value
Derivatives:
Derivative liability	35
Reinsurance related embedded derivatives, included in accounts payable and accrued liabilities \| Carrying Value
Derivatives:
Derivative liability	35
Asset-backed securities
Assets
Fixed maturity securities, available for sale	5,610
Asset-backed securities \| Level 1
Assets
Fixed maturity securities, available for sale	0
Asset-backed securities \| Level 2
Assets
Fixed maturity securities, available for sale	4,594
Asset-backed securities \| Level 3
Assets
Fixed maturity securities, available for sale	1,016
Asset-backed securities \| Fair Value
Assets
Fixed maturity securities, available for sale	5,610
Asset-backed securities \| Carrying Value
Assets
Fixed maturity securities, available for sale	5,610
Commercial mortgage-backed securities
Assets
Fixed maturity securities, available for sale	2,582	22
Commercial mortgage-backed securities \| Level 1
Assets
Fixed maturity securities, available for sale	0	0
Commercial mortgage-backed securities \| Level 2
Assets
Fixed maturity securities, available for sale	2,556	22
Commercial mortgage-backed securities \| Level 3
Assets
Fixed maturity securities, available for sale	26	0
Commercial mortgage-backed securities \| Fair Value
Assets
Fixed maturity securities, available for sale	2,582	22
Commercial mortgage-backed securities \| Carrying Value
Assets
Fixed maturity securities, available for sale	2,582	22
Corporates
Assets
Fixed maturity securities, available for sale	13,014	1,556
Corporates \| Level 1
Assets
Fixed maturity securities, available for sale	0	0
Corporates \| Level 2
Assets
Fixed maturity securities, available for sale	11,750	1,540
Corporates \| Level 3
Assets
Fixed maturity securities, available for sale	1,264	17
Corporates \| Fair Value
Assets
Fixed maturity securities, available for sale	13,014	1,557
Corporates \| Carrying Value
Assets
Fixed maturity securities, available for sale	13,014	1,557
Hybrids
Assets
Fixed maturity securities, available for sale	1,003	31
Hybrids \| Level 1
Assets
Fixed maturity securities, available for sale	286	0
Hybrids \| Level 2
Assets
Fixed maturity securities, available for sale	713	30
Hybrids \| Level 3
Assets
Fixed maturity securities, available for sale	4	0
Hybrids \| Fair Value
Assets
Fixed maturity securities, available for sale	1,003	30
Hybrids \| Carrying Value
Assets
Fixed maturity securities, available for sale	1,003	30
Municipals \| Level 1
Assets
Fixed maturity securities, available for sale	0	0
Municipals \| Level 2
Assets
Fixed maturity securities, available for sale	1,428	93
Municipals \| Level 3
Assets
Fixed maturity securities, available for sale	40	0
Municipals \| Fair Value
Assets
Fixed maturity securities, available for sale	1,468	93
Municipals \| Carrying Value
Assets
Fixed maturity securities, available for sale	1,468	93
Residential mortgage-backed securities
Assets
Fixed maturity securities, available for sale	927	40
Residential mortgage-backed securities \| Level 1
Assets
Fixed maturity securities, available for sale	0	0
Residential mortgage-backed securities \| Level 2
Assets
Fixed maturity securities, available for sale	418	40
Residential mortgage-backed securities \| Level 3
Assets
Fixed maturity securities, available for sale	509	0
Residential mortgage-backed securities \| Fair Value
Assets
Fixed maturity securities, available for sale	927	40
Residential mortgage-backed securities \| Carrying Value
Assets
Fixed maturity securities, available for sale	927	40
U.S. Government
Assets
Fixed maturity securities, available for sale	311	288
U.S. Government \| Level 1
Assets
Fixed maturity securities, available for sale	0	0
U.S. Government \| Level 2
Assets
Fixed maturity securities, available for sale	311	288
U.S. Government \| Level 3
Assets
Fixed maturity securities, available for sale	0	0
U.S. Government \| Fair Value
Assets
Fixed maturity securities, available for sale	311	288
U.S. Government \| Carrying Value
Assets
Fixed maturity securities, available for sale	311	288
Foreign Governments
Assets
Fixed maturity securities, available for sale	199	60
Foreign Governments \| Level 1
Assets
Fixed maturity securities, available for sale	0	0
Foreign Governments \| Level 2
Assets
Fixed maturity securities, available for sale	183	60
Foreign Governments \| Level 3
Assets
Fixed maturity securities, available for sale	16	0
Foreign Governments \| Fair Value
Assets
Fixed maturity securities, available for sale	199	60
Foreign Governments \| Carrying Value
Assets
Fixed maturity securities, available for sale	199	60
Equity securities \| Level 1
Assets
Equity securities	702
Equity securities \| Level 2
Assets
Equity securities	0
Equity securities \| Level 3
Assets
Equity securities	1
Equity securities \| Fair Value
Assets
Equity securities	703
Equity securities \| Carrying Value
Assets
Equity securities	703
Preferred securities
Assets
Equity securities	1,203	323
Preferred securities \| Level 1
Assets
Equity securities	502	65
Preferred securities \| Level 2
Assets
Equity securities	701	258
Preferred securities \| Level 3
Assets
Equity securities	0	0
Preferred securities \| Fair Value
Assets
Equity securities	1,203	323
Preferred securities \| Carrying Value
Assets
Equity securities	1,203	323
Other long-term investments \| Level 1
Assets
Other long-term investments	0	0
Other long-term investments \| Level 2
Assets
Other long-term investments	0	0
Other long-term investments \| Level 3
Assets
Other long-term investments	44	120
Other long-term investments \| Fair Value
Assets
Other long-term investments	44	120
Other long-term investments \| Carrying Value
Assets
Other long-term investments	$ 44	$ 120

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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