Litigation and Contingencies (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Average paid claim reduction due to curtailments (as a percent)	5.50%	5.50%
Maximum exposure associated with other discussions and legal proceedings	$ 291