Net Income Per Limited Partner Unit - Schedule of Allocation of Net Income to Arrive at Net Income Per Limited Partner Unit (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Limited Partners Capital Account [Line Items]
Net income	$ 73.0	$ 68.0
Less: Net income attributable to noncontrolling interests	2.2	12.7
Net income attributable to the Partnership	70.8	55.3
Distribution declared	63.6	41.7
Income in excess of distributions	7.2	13.6
General Partner
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership	12.1	3.1
Distribution declared	12.0	2.9
Income in excess of distributions	0.1	0.2
Limited Partners' Common Units
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership	58.7	30.5
Distribution declared	51.6	23.0
Income in excess of distributions	7.1	7.5
Limited Partner's Subordinated Units
Limited Partners Capital Account [Line Items]
Net income attributable to the Partnership		21.7
Distribution declared	$ 0.0	15.8
Income in excess of distributions		$ 5.9