Inventories (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Available-for-Sale Inventory by Product Type [Abstract]
NGLs		$ 740.5		$ 740.5		$ 579.1
Petrochemicals and refined products		158.0		158.0		295.6
Crude oil		152.2		152.2		97.8
Natural gas		34.7		34.7		41.7
Total		1,085.4		1,085.4		$ 1,014.2
Summary of cost of sales and lower of cost or market adjustments [Abstract]
Cost of sales	[1]	4,419.9	$ 10,455.1	15,355.9	$ 32,213.1
Lower of cost or market adjustments		$ 2.1	$ 6.7	$ 6.1	$ 14.6

[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.