Properties, Plants and Equipment (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Impairment of Long-Lived Assets Held-for-use	$ 19,200,000	$ 344,800,000	$ 0	$ 0
Capitalized interest		5,000,000	8,000,000	5,500,000
Depreciation expense		286,500,000	$ 247,900,000	$ 233,300,000
Refining facilities
Property, Plant and Equipment [Line Items]
Impairment of Long-Lived Assets Held-for-use		$ 0