Inventories (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Available-for-Sale Inventory by Product Type [Abstract]
NGLs		$ 625.8		$ 639.9
Petrochemicals and refined products		335.7		148.0
Crude oil		248.7		222.1
Natural gas		21.9		28.1
Total		1,232.1		$ 1,038.1
Summary of cost of sales and lower of cost or market adjustments [Abstract]
Cost of sales	[1]	3,208.3	$ 5,678.1
Lower of cost or market adjustments		$ 5.3	$ 3.5

[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.