Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016	Apr. 26, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Non-cash modifications of certain mortgage loans, fixed income securities, limited partnerships and other investments, as well as mergers completed with equity securities	$ 105	$ 63
Liabilities assumed	34
Net change in proceeds managed
Net change in fixed income securities	(126)	0
Net change in short-term investments	175	6
Operating cash flow provided	49	6
Net change in cash	0	1
Net change in proceeds managed	49	7
Change in Liabilities for Collateral
Liabilities for collateral, beginning of period	(550)	(510)
Liabilities for collateral, end of period	(501)	(503)
Operating cash flow used	(49)	$ (7)
Notes issued	$ 325				$ 275
Kennett Capital Inc | Subsidiary Issuer | Surplus Notes Due 2036 at 4.14 Percent
Change in Liabilities for Collateral
Notes issued			$ 50	$ 50