Acquisitions - Bridge Terminal Transport - Additional Information (Details) - USD ($) $ in Millions		6 Months Ended
	May 04, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired		$ 0.0	$ 1,610.7
Business combination, consideration transferred, shares of stock		0.0	$ 1.5
Goodwill		$ 4,732.0		$ 4,610.6
BTT
Business Acquisition [Line Items]
Consideration	$ 103.8
Acquisition of businesses, net of cash acquired	103.1
Business combination, consideration transferred, shares of stock	0.7
Goodwill	56.5
Fair value of intangible assets	$ 30.0