Investments - Allowance for credit losses on fixed maturities (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Jun. 30, 2020	Jun. 30, 2020	Jan. 01, 2020
Allowance for Credit Losses [Roll Forward]
Beginning balance		$ 61	$ 0
Impact of adoption of new accounting policy		61	0
Initial allowance for purchased securities with credit deterioration		1	1
Provision for expected credit losses on securities with no previous allowance		6	67
Additions (reductions) to previously recognized expected credit losses		(7)	(7)
Reductions due to sales or redemptions		0	0
Ending balance		61	61
Structured securities
Allowance for Credit Losses [Roll Forward]
Beginning balance	[1]	37	0
Impact of adoption of new accounting policy	[1]	39	0	$ 0
Initial allowance for purchased securities with credit deterioration	[1]	1	1
Provision for expected credit losses on securities with no previous allowance	[1]	2	39
Additions (reductions) to previously recognized expected credit losses	[1]	(1)	(1)
Reductions due to sales or redemptions	[1]	0	0
Ending balance	[1]	39	39
Corporate and other
Allowance for Credit Losses [Roll Forward]
Beginning balance		24	0
Impact of adoption of new accounting policy		22	0	0
Initial allowance for purchased securities with credit deterioration		0	0
Provision for expected credit losses on securities with no previous allowance		4	28
Additions (reductions) to previously recognized expected credit losses		(6)	(6)
Reductions due to sales or redemptions		0	0
Ending balance		$ 22	$ 22
Accounting Standards Update 2016-13
Allowance for Credit Losses [Roll Forward]
Impact of adoption of new accounting policy				$ 0

[1] Includes mortgage-backed securities, collateralized loan obligations and other asset-backed securities.