Inventories (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Available-for-Sale Inventory by Product Type [Abstract]
NGLs		$ 1,202.4		$ 1,202.4		$ 639.9
Petrochemicals and refined products		230.4		230.4		148.0
Crude oil		299.3		299.3		222.1
Natural gas		30.4		30.4		28.1
Total		1,762.5		1,762.5		$ 1,038.1
Inventory held for certain market opportunities		1,000.0		1,000.0
Summary of cost of sales and lower of cost or market adjustments [Abstract]
Cost of sales	[1]	4,088.6	$ 4,419.9	11,135.6	$ 15,355.9
Lower of cost or market adjustments within cost of sales		$ 1.5	$ 2.1	$ 7.6	$ 6.1

[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.