Business Segments, Segment Reporting Information (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Information by business segment [Abstract]
Gross operating margin										$ 7,291.0		$ 5,674.6		$ 5,230.7
Revenues from third parties										36,426.5		29,196.5		22,965.6
Revenues from related parties										107.7		45.0		56.7
Intersegment and intrasegment revenues										0.0		0.0		0.0
Total revenues		$ 9,182.3	$ 9,585.9	$ 8,467.5	$ 9,298.5	$ 8,426.6	$ 6,886.9	$ 6,607.6	$ 7,320.4	36,534.2	[1]	29,241.5	[2]	23,022.3	[2]
Equity in income (loss) of unconsolidated affiliates										480.0		426.0		362.0
Property, plant and equipment, net		38,737.6				35,620.4				38,737.6		35,620.4		33,292.5
Investments in unconsolidated affiliates		2,615.1				2,659.4				2,615.1		2,659.4		2,677.3
Intangible assets, net		3,608.4				3,690.3				3,608.4		3,690.3		3,864.1
Goodwill		5,745.2				5,745.2				5,745.2		5,745.2		5,745.2
Segment assets		50,706.3				47,715.3				50,706.3		47,715.3		45,579.1
NGL Pipelines and Services [Member]
Information by business segment [Abstract]
Total revenues										15,648.9	[1]	12,468.0	[2]	10,242.5	[2]
Equity in income (loss) of unconsolidated affiliates										117.0		73.4		61.4
Intangible assets, net		380.1				322.3				380.1		322.3
Crude Oil Pipelines & Services [Member]
Information by business segment [Abstract]
Total revenues										11,042.6	[1]	8,156.8	[2]	6,515.0	[2]
Equity in income (loss) of unconsolidated affiliates										365.4		358.4		311.9
Intangible assets, net		2,094.6				2,186.5				2,094.6		2,186.5
Natural Gas Pipelines & Services [Member]
Information by business segment [Abstract]
Total revenues										3,454.4	[1]	3,145.6	[2]	2,543.0	[2]
Equity in income (loss) of unconsolidated affiliates										6.8		3.8		3.8
Intangible assets, net		979.3				1,018.4				979.3		1,018.4
Petrochemical & Refined Products Services [Member]
Information by business segment [Abstract]
Total revenues										6,388.3	[1]	5,471.1	[2]	3,721.8	[2]
Equity in income (loss) of unconsolidated affiliates	[3]									(9.2)		(9.6)		(15.1)
Intangible assets, net		154.4				163.1				154.4		163.1
Reportable Business Segments [Member] | NGL Pipelines and Services [Member]
Information by business segment [Abstract]
Gross operating margin										3,830.7		3,258.3		2,990.6
Revenues from third parties										15,630.5		12,455.7		10,232.7
Revenues from related parties										18.4		12.3		9.8
Intersegment and intrasegment revenues										26,453.6		27,278.6		19,150.0
Total revenues										42,102.5		39,746.6		29,392.5
Equity in income (loss) of unconsolidated affiliates										117.0		73.4		61.4
Property, plant and equipment, net		14,845.4				13,831.2				14,845.4		13,831.2		14,091.5
Investments in unconsolidated affiliates		662.0				733.9				662.0		733.9		750.4
Intangible assets, net		380.1				322.3				380.1		322.3		350.2
Goodwill		2,651.7				2,651.7				2,651.7		2,651.7		2,651.7
Segment assets		18,539.2				17,539.1				18,539.2		17,539.1		17,843.8
Reportable Business Segments [Member] | Crude Oil Pipelines & Services [Member]
Information by business segment [Abstract]
Gross operating margin										1,511.3		987.2		854.6
Revenues from third parties										10,968.2		8,137.2		6,478.7
Revenues from related parties										74.4		19.6		36.3
Intersegment and intrasegment revenues										35,490.4		15,943.0		9,052.0
Total revenues										46,533.0		24,099.8		15,567.0
Equity in income (loss) of unconsolidated affiliates										365.4		358.4		311.9
Property, plant and equipment, net		5,847.7				5,208.4				5,847.7		5,208.4		4,216.1
Investments in unconsolidated affiliates		1,867.5				1,839.2				1,867.5		1,839.2		1,824.6
Intangible assets, net		2,094.6				2,186.5				2,094.6		2,186.5		2,279.0
Goodwill		1,841.0				1,841.0				1,841.0		1,841.0		1,841.0
Segment assets		11,650.8				11,075.1				11,650.8		11,075.1		10,160.7
Reportable Business Segments [Member] | Natural Gas Pipelines & Services [Member]
Information by business segment [Abstract]
Gross operating margin										891.2		714.5		734.9
Revenues from third parties										3,439.5		3,132.5		2,532.4
Revenues from related parties										14.9		13.1		10.6
Intersegment and intrasegment revenues										721.9		850.8		668.5
Total revenues										4,176.3		3,996.4		3,211.5
Equity in income (loss) of unconsolidated affiliates										6.8		3.8		3.8
Property, plant and equipment, net		8,303.8				8,375.0				8,303.8		8,375.0		8,403.0
Investments in unconsolidated affiliates		22.8				20.8				22.8		20.8		21.7
Intangible assets, net		979.3				1,018.4				979.3		1,018.4		1,054.5
Goodwill		296.3				296.3				296.3		296.3		296.3
Segment assets		9,602.2				9,710.5				9,602.2		9,710.5		9,775.5
Reportable Business Segments [Member] | Petrochemical & Refined Products Services [Member]
Information by business segment [Abstract]
Gross operating margin										1,057.8		714.6		650.6
Revenues from third parties										6,388.3		5,471.1		3,721.8
Revenues from related parties										0.0		0.0		0.0
Intersegment and intrasegment revenues										2,917.5		1,766.9		1,234.8
Total revenues										9,305.8		7,238.0		4,956.6
Equity in income (loss) of unconsolidated affiliates										(9.2)		(9.6)		(15.1)
Property, plant and equipment, net		6,213.9				3,507.7				6,213.9		3,507.7		3,261.2
Investments in unconsolidated affiliates		62.8				65.5				62.8		65.5		80.6
Intangible assets, net		154.4				163.1				154.4		163.1		180.4
Goodwill		956.2				956.2				956.2		956.2		956.2
Segment assets		7,387.3				4,692.5				7,387.3		4,692.5		4,478.4
Eliminations [Member]
Information by business segment [Abstract]
Revenues from third parties										0.0		0.0		0.0
Revenues from related parties										0.0		0.0		0.0
Intersegment and intrasegment revenues										(65,583.4)		(45,839.3)		(30,105.3)
Total revenues										(65,583.4)		(45,839.3)		(30,105.3)
Equity in income (loss) of unconsolidated affiliates										0.0		0.0		0.0
Adjustments [Member]
Information by business segment [Abstract]
Property, plant and equipment, net		3,526.8				4,698.1				3,526.8		4,698.1		3,320.7
Investments in unconsolidated affiliates		0.0				0.0				0.0		0.0		0.0
Intangible assets, net		0.0				0.0				0.0		0.0		0.0
Goodwill		0.0				0.0				0.0		0.0		0.0
Segment assets		$ 3,526.8				$ 4,698.1				$ 3,526.8		$ 4,698.1		$ 3,320.7

[1] Revenues are accounted for under ASC 606 upon implementation at January 1, 2018.

[2] Revenues are accounted for under ASC 605 for historical periods prior to January 1, 2018.

[3] Losses are primarily attributable to our investment in Centennial. As a result of a trend in declining earnings, we estimated the fair value of this equity-method investment during each of the last three fiscal years. Our estimates, based on a combination of market and income approaches, indicate that the fair value of this investment remains in excess of its carrying value.