Investments - OTTI losses by asset type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Realized capital gains and losses by asset type
Fixed income securities	$ 2	$ (37)
Total credit losses by asset type	2	(36)
Commitments to fund commercial mortgage loans, bank loans and agent loans	0	(1)
Fixed income securities
Realized capital gains and losses by asset type
Fixed income securities	2	(2)
Corporate
Realized capital gains and losses by asset type
Fixed income securities	1	(1)
ABS
Realized capital gains and losses by asset type
Fixed income securities	1	0
MBS
Realized capital gains and losses by asset type
Fixed income securities	0	(1)
Mortgage loans
Realized capital gains and losses by asset type
Total credit losses by asset type	6	(9)
Limited partnership interests
Realized capital gains and losses by asset type
Total credit losses by asset type	0	(5)
Bank loans, net
Realized capital gains and losses by asset type
Total credit losses by asset type	$ (6)	$ (20)