Investments - Available for sale fixed maturities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	$ 40,408		$ 44,524
Fixed maturities, available for sale, allowance for expected credit losses	40		0
Available for sale (AFS) fixed maturities	43,207		46,505
Total fixed maturities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	40,408		44,524
Fixed maturities, available for sale, allowance for expected credit losses	40		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	2,957		2,069
Fixed maturities, Available for sale, Gross Unrealized, Losses	(118)		(88)
Available for sale (AFS) fixed maturities	43,207		46,505
Total fixed maturities \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	2,839		1,981
U.S. Government and government agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	231		199
Fixed maturities, available for sale, allowance for expected credit losses	0		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	11		10
Fixed maturities, Available for sale, Gross Unrealized, Losses	0		0
Available for sale (AFS) fixed maturities	242		209
U.S. Government and government agencies \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	11		10
States, municipalities and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	5,249		6,604
Fixed maturities, available for sale, allowance for expected credit losses	0		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	486		363
Fixed maturities, Available for sale, Gross Unrealized, Losses	(2)		(4)
Available for sale (AFS) fixed maturities	5,733		6,963
States, municipalities and political subdivisions \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	484		359
Foreign government
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	203		170
Fixed maturities, available for sale, allowance for expected credit losses	0		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	8		3
Fixed maturities, Available for sale, Gross Unrealized, Losses	0		(1)
Available for sale (AFS) fixed maturities	211		172
Foreign government \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	8		2
Residential MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	2,812		2,900
Fixed maturities, available for sale, allowance for expected credit losses	3		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	251		265
Fixed maturities, Available for sale, Gross Unrealized, Losses	(5)		(5)
Available for sale (AFS) fixed maturities	3,055		3,160
Residential MBS \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	246		260
Commercial MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	748		896
Fixed maturities, available for sale, allowance for expected credit losses	0		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	43		31
Fixed maturities, Available for sale, Gross Unrealized, Losses	(1)		0
Available for sale (AFS) fixed maturities	790		927
Commercial MBS \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	42		31
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	4,556		4,307
Fixed maturities, available for sale, allowance for expected credit losses	13		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	27		10
Fixed maturities, Available for sale, Gross Unrealized, Losses	(17)		(37)
Collateralized loan obligations \| Managed by third parties
Debt Securities, Available-for-sale [Line Items]
Available for sale (AFS) fixed maturities	4,553		4,280
Collateralized loan obligations \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	10		(27)
Other asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	7,138		6,992
Fixed maturities, available for sale, allowance for expected credit losses	18		0
Fixed maturities, Available for sale, Gross Unrealized, Gains	169		156
Fixed maturities, Available for sale, Gross Unrealized, Losses	(66)		(20)
Available for sale (AFS) fixed maturities	7,223		7,128
Other asset-backed securities \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	103		136
Corporate and other
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	19,471		22,456
Fixed maturities, available for sale, allowance for expected credit losses	6	$ 0	0
Fixed maturities, Available for sale, Gross Unrealized, Gains	1,962		1,231
Fixed maturities, Available for sale, Gross Unrealized, Losses	(27)		(21)
Available for sale (AFS) fixed maturities	21,400		23,666
Corporate and other \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	$ 1,935		$ 1,210

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on 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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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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