Inventories (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Available-for-Sale Inventory by Product Type [Abstract]
NGLs	$ 1,085.8				$ 1,085.8				$ 594.3
Petrochemicals and refined products	448.2				448.2				304.5
Crude oil	254.8				254.8				119.4
Natural gas	73.6				73.6				70.2
Total	1,862.4				1,862.4				1,088.4
Summary of cost of sales and lower of cost or market adjustments [Abstract]
Cost of sales	10,371.3	[1]	8,794.0	[1]	29,522.1	[1]	26,655.0	[1]
Lower of cost or market adjustments	$ 4.5		$ 2.2		$ 14.9		$ 16.1

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