Deferred Policy Acquisition Costs Level 4 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred Policy Acquisition Costs	$ 463	$ 542	$ 521
Deferred Policy Acquisition Costs, Additions	2	7	7
Deferred Policy Acquisition Cost, Amortization Expense, Other	(51)	(40)	(82)
Deferred Policy Acquisition Cost, Amortization Expense, Assumption Change	3	(74)	13
Deferred Policy Acquisition Cost, Unrealized Investment Gain (Loss)	(12)	28	83
Deferred Policy Acquisition Costs	$ 405	$ 463	$ 542