Inventories (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Inventory by Product Type [Abstract]
NGLs		$ 897.1		$ 897.1		$ 1,156.1
Petrochemicals and refined products		377.4		377.4		220.7
Crude oil		313.2		313.2		360.0
Natural gas		16.6		16.6		33.7
Total		1,604.3		1,604.3		$ 1,770.5
Summary of cost of sales and lower of cost or net realizable value adjustments [Abstract]
Cost of sales	[1]	4,731.1	$ 3,838.7	10,066.8	$ 7,047.0
Lower of cost or net realizable value adjustments within cost of sales		$ 2.6	$ 0.8	$ 6.0	$ 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.