Litigation and Contingencies (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2009	Dec. 31, 2015
Curtailments [Abstract]
Average paid claim reduction due to curtailments (in hundredths)	5.50%		6.70%
Claims resolved by rescissions [Abstract]
Percentage of claims received in a quarter resolved by rescission, lower range limit (in hundredths)	5.00%
Percentage of claims received in a quarter resolved by rescission, upper range limit (in hundredths)		28.00%
Maximum exposure associated with other discussions and legal proceedings	$ 193
Other Legal Proceedings [Abstract]
Underwriting remedy expense			$ 1