Commitments and Contingencies (Details Textual) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Commitments and Contingencies (Textual) [Abstract]
Site contingency number of sites checked	6
Sites in various stages of follow-up	4
Sites with limited soil and ground water impact	2
Sites requiring additional investigation	2
Minimum [Member]
Commitments and Contingencies (Textual) [Abstract]
Notice required to cancel purchase agreements, days	30 days
Maximum [Member]
Commitments and Contingencies (Textual) [Abstract]
Notice required to cancel purchase agreements, days	120 days
U.S. Liquids [Member]
Commitments and Contingencies (Textual) [Abstract]
Site contingency number of sites checked	5
U.S. Gas [Member]
Commitments and Contingencies (Textual) [Abstract]
Site contingency number of sites checked	1
Canada [Member]
Commitments and Contingencies (Textual) [Abstract]
Asset retirement obligation liability	$ 25.0
Estimated cost to retire facilities	$ 138.9