Business Segments, Consolidated Revenues and Expenses (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Consolidated Revenues [Abstract]
Total consolidated revenues		$ 5,005.3	$ 7,472.5
Operating costs and expenses:
Cost of sales	[1]	3,208.3	5,678.1
Other operating costs and expenses	[2]	573.8	559.8
Depreciation, amortization and accretion		358.2	345.3
Net losses (gains) attributable to asset sales		4.9	(0.1)
Non-cash asset impairment charges		1.7	33.3
General and administrative costs		43.9	49.3
Total consolidated costs and expenses		4,190.8	6,665.7
NGL Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Sales of NGLs and related products		1,943.5	2,242.2
Midstream services		460.3	434.1
Total consolidated revenues		2,403.8	2,676.3
Crude Oil Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Sales of crude oil		1,121.1	2,570.7
Midstream services		167.5	107.3
Total consolidated revenues		1,288.6	2,678.0
Natural Gas Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Sales of natural gas		315.0	476.3
Midstream services		235.0	257.6
Total consolidated revenues		550.0	733.9
Petrochemical & Refined Products Services [Member]
Consolidated Revenues [Abstract]
Sales of petrochemicals and refined products		553.2	1,151.0
Midstream services		209.7	198.1
Total consolidated revenues		762.9	1,349.1
Offshore Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Sales of crude oil		0.0	1.1
Midstream services		0.0	34.1
Total consolidated revenues		$ 0.0	$ 35.2

[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.

[2] Represents cost of operating our plants, pipelines and other fixed assets, excluding depreciation, amortization and accretion charges.