Claim and Claim Adjustment Expense Reserves (Impact of Loss Portfolio Transfer on the Consolidated Statement of Operations) (Details) - Loss Portfolio Transfer [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net AEP adverse development before consideration of LPT	$ 200	$ 200	$ 150	$ 0
Retroactive reinsurance benefit recognized		(107)	(85)	(13)
Pretax impact of deferred retroactive reinsurance benefit		$ 93	$ 65	$ (13)