Investments - Allowance for credit losses on fixed maturities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 7	$ 10	$ 9	$ 12
Initial allowance for purchased securities with credit deterioration	0	0	0	0
Provision for expected credit losses on securities with no previous allowance	1	0	1	0
Additions (reductions) to previously recognized expected credit losses	0	0	(2)	(1)
Reductions due to sales or redemptions	(1)	(1)	(1)	(2)
Ending balance	7	9	7	9
Structured securities
Allowance for Credit Losses [Roll Forward]
Beginning balance	6	9	8	10
Initial allowance for purchased securities with credit deterioration	0	0	0	0
Provision for expected credit losses on securities with no previous allowance	1	0	1	0
Additions (reductions) to previously recognized expected credit losses	0	(1)	(2)	(2)
Reductions due to sales or redemptions	0	0	0	0
Ending balance	7	8	7	8
Corporate and other
Allowance for Credit Losses [Roll Forward]
Beginning balance	1	1	1	2
Initial allowance for purchased securities with credit deterioration	0	0	0	0
Provision for expected credit losses on securities with no previous allowance	0	0	0	0
Additions (reductions) to previously recognized expected credit losses	0	1	0	1
Reductions due to sales or redemptions	(1)	(1)	(1)	(2)
Ending balance	$ 0	$ 1	$ 0	$ 1