Investments - Allowance for credit losses on fixed maturities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 16	$ 7	$ 11	$ 9
Provision for expected credit losses on securities with no previous allowance	3	2	9	3
Additions (reductions) to previously recognized expected credit losses	1	0	0	(2)
Reductions due to sales or redemptions	0	0	0	(1)
Ending balance	20	9	20	9
Structured securities
Allowance for Credit Losses [Roll Forward]
Beginning balance	11	7	10	8
Provision for expected credit losses on securities with no previous allowance	0	2	1	3
Additions (reductions) to previously recognized expected credit losses	1	0	1	(2)
Reductions due to sales or redemptions	0	0	0	0
Ending balance	12	9	12	9
Corporate and other
Allowance for Credit Losses [Roll Forward]
Beginning balance	5	0	1	1
Provision for expected credit losses on securities with no previous allowance	3	0	8	0
Additions (reductions) to previously recognized expected credit losses	0	0	(1)	0
Reductions due to sales or redemptions	0	0	0	(1)
Ending balance	$ 8	$ 0	$ 8	$ 0