Inventories (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Inventory by Product Type [Abstract]
NGLs		$ 849.7		$ 647.7
Petrochemicals and refined products		287.6		264.7
Crude oil		533.8		593.4
Natural gas		9.4		16.3
Total		1,680.5		$ 1,522.1
Summary of cost of sales and lower of cost or net realizable value adjustments [Abstract]
Cost of sales	[1]	5,835.6	$ 7,140.4
Lower of cost or net realizable value adjustments recognized within cost of sales		$ 5.4	$ 1.9

[1] Cost of sales is a component of "Operating costs and expenses" as presented on our Unaudited Condensed Statements of Consolidated Operations. Fluctuations in these amounts are primarily due to changes in energy commodity prices and sales volumes associated with our marketing activities.