Claim and Claim Adjustment Expense Reserves - Impact of Loss Portfolio Transfer on the Consolidated Statement of Operations (Details) - Loss Portfolio Transfer - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Liability for Claims and Claims Adjustment Expense [Line Items]
Net A&EP adverse development before consideration of LPT	$ 60	$ 200
Retroactive reinsurance benefit recognized	(40)	(73)
Pretax impact of A&EP reserve development and the LPT	$ 20	$ 127