Equity, Cash Distributions (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								6 Months Ended
	Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018	Jun. 30, 2018		Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Distribution Made to Member or Limited Partner
Loss attributable to Predecessors	$ 0.0					$ 16.0	[1]	$ 8.0	$ 0.0	$ 24.0	[1]
Distributions to preferred unitholders									21.0	8.0	[2]
Distribution to Partner, Waived Distribution	$ 0.0		$ 12.5		$ 15.0	15.0			12.5	30.0
Distribution Made to Limited Partner, Distributions Declared, Per Unit	$ 1.03		$ 1.03
Distributions to common unitholders	$ 240.0	[3]	$ 238.0	[3]					$ 480.0	$ 411.0	[2]
Distribution Made to Limited Partner, Distribution Date	May 15, 2019		Feb. 14, 2019
Distribution Made to Limited Partner, Date of Record	May 09, 2019		Feb. 05, 2019
Common
Distribution Made to Member or Limited Partner
Loss attributable to Predecessors						$ 0.0		$ 0.0

[1] Adjusted to include the historical results of the Predecessors. See Note 1 for further discussion.

[2] Adjusted to include the historical results of the Predecessors. See Note 1 for further discussion.

[3] This distribution is net of $12.5 million waived with respect to units held by our Sponsor and its affiliates for the three months ended March 31, 2019 and $15 million for the three months ended December 31, 2018. These distribution waivers were instituted in 2017 under the terms of our partnership agreement.