Business Segments, Consolidated Revenues and Expenses (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Revenues [Abstract]
Total consolidated revenues		$ 8,426.6	$ 6,886.9	$ 6,607.6	$ 7,320.4	$ 6,478.8	$ 5,920.4	$ 5,617.8	$ 5,005.3	$ 29,241.5	$ 23,022.3	$ 27,027.9
Operating costs and expenses:
Cost of sales	[1]									21,487.0	15,710.9	19,612.9
Other operating costs and expenses	[2]									2,500.1	2,425.6	2,449.4
Depreciation, amortization and accretion										1,531.3	1,456.7	1,428.2
Asset impairment and related charges										49.8	52.8	162.6
Net losses (gains) attributable to asset sales										(10.7)	(2.5)	15.6
General and administrative costs										181.1	160.1	192.6
Total costs and expenses										25,738.6	$ 19,803.6	$ 23,861.3
Vitol Holding B.V. [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										$ 3,288.3
Vitol Holding B.V. [Member] | Revenues [Member]
Consolidated Revenues [Abstract]
Largest non-affiliated customer percentage										11.20%	9.90%
Shell Oil Company [Member] | Revenues [Member]
Consolidated Revenues [Abstract]
Largest non-affiliated customer percentage												7.40%
NGL Pipelines and Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										$ 12,468.0	$ 10,242.5	$ 9,788.0
NGL Pipelines and Services [Member] | Vitol Holding B.V. [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										2,099.1
Crude Oil Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										8,156.8	6,515.0	10,305.9
Crude Oil Pipelines & Services [Member] | Vitol Holding B.V. [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										625.6
Natural Gas Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										3,145.6	2,543.0	2,743.3
Natural Gas Pipelines & Services [Member] | Vitol Holding B.V. [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										51.1
Petrochemical and Refined Products Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										5,471.1	3,721.8	4,111.9
Petrochemical and Refined Products Services [Member] | Vitol Holding B.V. [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										512.5
Offshore Pipelines And Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues										$ 0.0	$ 0.0	$ 78.8

[1] Cost of sales is a component of "Operating costs and expenses," as presented on our 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 the cost of operating our plants, pipelines and other fixed assets excluding: depreciation, amortization and accretion charges; asset impairment and related charges; and net losses (or gains) attributable to asset sales.