Commitments and Contingencies Litigation (Details) - Refinery outage [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Aug. 31, 2014	Mar. 31, 2017	Dec. 31, 2015	Dec. 31, 2016
Loss Contingencies [Line Items]
Damages sought	$ 48.5	$ 108.0	$ 61.7
Retention amount				$ 2.0