Deferred Policy Acquisition and Sales Inducement Costs - Deferred sales inducement costs activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred sales inducement costs activity
Balance, beginning of year	$ 27	$ 34	$ 36
Amortization charged to income	(5)	(5)	(4)
Effect of unrealized gains and losses	3	(2)	2
Balance, end of year	$ 25	$ 27	$ 34