Business Segments, Consolidated Revenues and Expenses (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Consolidated Revenues [Abstract]
Total consolidated revenues		$ 6,922.0	$ 7,964.1	$ 20,155.5	$ 24,783.9
Operating costs and expenses:
Cost of sales	[1]	4,313.7	5,276.5	12,331.9	16,721.5
Other operating costs and expenses	[2]	696.9	790.8	2,120.4	2,243.4
Depreciation, amortization and accretion		484.2	467.1	1,461.3	1,380.8
Asset impairment and related charges		77.0	39.4	90.4	51.2
Net gains attributable to asset sales		(0.6)	(0.1)	(2.1)	(2.6)
General and administrative costs		50.3	55.5	162.8	160.2
Total consolidated costs and expenses		5,621.5	6,629.2	16,164.7	20,554.5
NGL Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues		2,614.0	3,252.1	8,058.4	9,851.2
Crude Oil Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues		1,521.6	2,478.3	5,023.7	7,952.2
Natural Gas Pipelines & Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues		606.9	715.5	1,862.7	2,462.3
Petrochemical & Refined Products Services [Member]
Consolidated Revenues [Abstract]
Total consolidated revenues		$ 2,179.5	$ 1,518.2	$ 5,210.7	$ 4,518.2

[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 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.