Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Summary Of Significant Accounting Policies [Line Items]
Impaired Assets to be Disposed of by Method Other than Sale, Amount of Impairment Loss			$ 354.4
Percentage Disposition Exceeded Carrying Value Of Property Plant And Equipment	0.00%		0.00%
Deferred Finance Costs, Net	$ 39.2		$ 40.9
Goodwill [Roll Forward]
Goodwill at December 31, 2015	1,085.5
Goodwill impairment	109.7	$ 0.0
Goodwill at March 31, 2016	975.8		1,085.5
Marcellus
Goodwill [Roll Forward]
Goodwill at December 31, 2015	8.6
Goodwill impairment	8.6
Goodwill at March 31, 2016	0.0		8.6
Arrow
Goodwill [Roll Forward]
Goodwill at December 31, 2015	45.9
Goodwill impairment	0.0
Goodwill at March 31, 2016	45.9		45.9
Northeast Storage and Transportation
Goodwill [Roll Forward]
Goodwill at December 31, 2015	726.3
Goodwill impairment	0.0
Goodwill at March 31, 2016	726.3		726.3
COLT
Goodwill [Roll Forward]
Goodwill at December 31, 2015	44.9
Goodwill impairment	13.7
Goodwill at March 31, 2016	31.2		44.9
Supply and Logistics
Goodwill [Roll Forward]
Goodwill at December 31, 2015	167.2
Goodwill impairment	65.5
Goodwill at March 31, 2016	101.7		167.2
Storage and Terminals
Goodwill [Roll Forward]
Goodwill at December 31, 2015	50.5
Goodwill impairment	14.1
Goodwill at March 31, 2016	36.4		50.5
US Salt
Goodwill [Roll Forward]
Goodwill at December 31, 2015	12.6
Goodwill impairment	0.0
Goodwill at March 31, 2016	12.6		12.6
Trucking
Goodwill [Roll Forward]
Goodwill at December 31, 2015	29.5
Goodwill impairment	7.8
Goodwill at March 31, 2016	$ 21.7		$ 29.5
Minimum
Summary Of Significant Accounting Policies [Line Items]
Fair Value Inputs, Discount Rate	10.00%
Maximum
Summary Of Significant Accounting Policies [Line Items]
Fair Value Inputs, Discount Rate	19.00%