Supplemental Cash Flow Information - Net change (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Net change in proceeds managed
Net change in fixed income securities	$ 28	$ 78
Net change in short-term investments	(194)	(72)
Operating cash flow (used) provided	(166)	6
Net change in liabilities
Liabilities for collateral, beginning of period	(525)	(542)
Liabilities for collateral, end of period	(691)	(536)
Operating cash flow provided (used)	$ 166	$ (6)