Business Segments, Segment Reporting Information (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Information by business segment [Abstract]
Gross operating margin										$ 5,230.7	$ 5,332.1	$ 5,286.5
Revenues from third parties										22,965.6	26,955.6	47,879.7
Revenues from related parties										56.7	72.3	71.5
Intersegment and intrasegment revenues										0.0	0.0	0.0
Total revenues		$ 6,478.8	$ 5,920.4	$ 5,617.8	$ 5,005.3	$ 6,155.0	$ 6,307.9	$ 7,092.5	$ 7,472.5	23,022.3	27,027.9	47,951.2
Equity in income (loss) of unconsolidated affiliates										362.0	373.6	259.5
Property, plant and equipment, net		33,292.5				32,034.7				33,292.5	32,034.7	29,881.6
Investments in unconsolidated affiliates		2,677.3				2,628.5				2,677.3	2,628.5	3,042.0
Intangible assets, net		3,864.1				4,037.2				3,864.1	4,037.2	4,302.1
Goodwill		5,745.2				5,745.2				5,745.2	5,745.2	4,300.2	$ 2,080.0
Segment assets		45,579.1				44,445.6				45,579.1	44,445.6	41,525.9
NGL Pipelines and Services [Member]
Information by business segment [Abstract]
Total revenues										10,242.5	9,788.0	17,089.8
Equity in income (loss) of unconsolidated affiliates										61.4	57.5	30.6
Intangible assets, net		350.2				380.3				350.2	380.3
Goodwill		2,651.7				2,651.7				2,651.7	2,651.7	2,210.2	341.2
Crude Oil Pipelines & Services [Member]
Information by business segment [Abstract]
Total revenues										6,515.0	10,305.9	20,184.3
Equity in income (loss) of unconsolidated affiliates										311.9	281.4	184.6
Intangible assets, net		2,279.0				2,377.5				2,279.0	2,377.5
Goodwill		1,841.0				1,841.0				1,841.0	1,841.0	918.7	305.1
Natural Gas Pipelines & Services [Member]
Information by business segment [Abstract]
Total revenues										2,543.0	2,743.3	4,203.8
Equity in income (loss) of unconsolidated affiliates										3.8	3.8	3.6
Intangible assets, net		1,054.5				1,087.7				1,054.5	1,087.7
Goodwill		296.3				296.3				296.3	296.3	296.3	296.3
Petrochemical & Refined Products Services [Member]
Information by business segment [Abstract]
Total revenues										3,721.8	4,111.9	6,316.5
Equity in income (loss) of unconsolidated affiliates	[1]									(15.1)	(15.7)	(13.3)
Intangible assets, net		180.4				191.7				180.4	191.7
Goodwill		956.2				956.2				956.2	956.2	793.0	1,055.3
Offshore Pipelines And Services [Member]
Information by business segment [Abstract]
Total revenues										0.0	78.8	156.8
Equity in income (loss) of unconsolidated affiliates										0.0	46.6	54.0
Goodwill		0.0				0.0				0.0	0.0	82.0	$ 82.1
Reportable Business Segments [Member] | NGL Pipelines and Services [Member]
Information by business segment [Abstract]
Gross operating margin										2,990.6	2,771.6	2,877.7
Revenues from third parties										10,232.7	9,779.0	17,078.4
Revenues from related parties										9.8	9.0	11.4
Intersegment and intrasegment revenues										19,150.0	10,217.9	13,716.5
Total revenues										29,392.5	20,005.9	30,806.3
Equity in income (loss) of unconsolidated affiliates										61.4	57.5	30.6
Property, plant and equipment, net		14,091.5				12,909.7				14,091.5	12,909.7	11,766.9
Investments in unconsolidated affiliates		750.4				718.7				750.4	718.7	682.3
Intangible assets, net		350.2				380.3				350.2	380.3	689.2
Goodwill		2,651.7				2,651.7				2,651.7	2,651.7	2,210.2
Segment assets		17,843.8				16,660.4				17,843.8	16,660.4	15,348.6
Reportable Business Segments [Member] | Crude Oil Pipelines & Services [Member]
Information by business segment [Abstract]
Gross operating margin										854.6	961.9	762.5
Revenues from third parties										6,478.7	10,258.3	20,151.9
Revenues from related parties										36.3	47.6	32.4
Intersegment and intrasegment revenues										9,052.0	5,162.0	12,678.7
Total revenues										15,567.0	15,467.9	32,863.0
Equity in income (loss) of unconsolidated affiliates										311.9	281.4	184.6
Property, plant and equipment, net		4,216.1				3,550.3				4,216.1	3,550.3	2,332.2
Investments in unconsolidated affiliates		1,824.6				1,813.4				1,824.6	1,813.4	1,767.7
Intangible assets, net		2,279.0				2,377.5				2,279.0	2,377.5	2,223.6
Goodwill		1,841.0				1,841.0				1,841.0	1,841.0	918.7
Segment assets		10,160.7				9,582.2				10,160.7	9,582.2	7,242.2
Reportable Business Segments [Member] | Natural Gas Pipelines & Services [Member]
Information by business segment [Abstract]
Gross operating margin										734.9	782.6	803.3
Revenues from third parties										2,532.4	2,729.5	4,182.6
Revenues from related parties										10.6	13.8	21.2
Intersegment and intrasegment revenues										668.5	662.1	1,106.7
Total revenues										3,211.5	3,405.4	5,310.5
Equity in income (loss) of unconsolidated affiliates										3.8	3.8	3.6
Property, plant and equipment, net		8,403.0				8,620.0				8,403.0	8,620.0	8,835.5
Investments in unconsolidated affiliates		21.7				22.5				21.7	22.5	23.2
Intangible assets, net		1,054.5				1,087.7				1,054.5	1,087.7	972.9
Goodwill		296.3				296.3				296.3	296.3	296.3
Segment assets		9,775.5				10,026.5				9,775.5	10,026.5	10,127.9
Reportable Business Segments [Member] | Petrochemical & Refined Products Services [Member]
Information by business segment [Abstract]
Gross operating margin										650.6	718.5	681.0
Revenues from third parties										3,721.8	4,111.9	6,316.5
Revenues from related parties										0.0	0.0	0.0
Intersegment and intrasegment revenues										1,234.8	1,126.0	1,779.6
Total revenues										4,956.6	5,237.9	8,096.1
Equity in income (loss) of unconsolidated affiliates										(15.1)	(15.7)	(13.3)
Property, plant and equipment, net		3,261.2				3,060.7				3,261.2	3,060.7	3,047.2
Investments in unconsolidated affiliates		80.6				73.9				80.6	73.9	75.1
Intangible assets, net		180.4				191.7				180.4	191.7	374.8
Goodwill		956.2				956.2				956.2	956.2	793.0
Segment assets		4,478.4				4,282.5				4,478.4	4,282.5	4,290.1
Reportable Business Segments [Member] | Offshore Pipelines And Services [Member]
Information by business segment [Abstract]
Gross operating margin										0.0	97.5	162.0
Revenues from third parties										0.0	76.9	150.3
Revenues from related parties										0.0	1.9	6.5
Intersegment and intrasegment revenues										0.0	0.6	6.5
Total revenues										0.0	79.4	163.3
Equity in income (loss) of unconsolidated affiliates										0.0	46.6	54.0
Property, plant and equipment, net		0.0				0.0				0.0	0.0	1,145.1
Investments in unconsolidated affiliates		0.0				0.0				0.0	0.0	493.7
Intangible assets, net		0.0				0.0				0.0	0.0	41.6
Goodwill		0.0				0.0				0.0	0.0	82.0
Segment assets		0.0				0.0				0.0	0.0	1,762.4
Adjustments [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										(30,105.3)	(17,168.6)	(29,288.0)
Total revenues										(30,105.3)	(17,168.6)	(29,288.0)
Equity in income (loss) of unconsolidated affiliates										0.0	0.0	0.0
Property, plant and equipment, net		3,320.7				3,894.0				3,320.7	3,894.0	2,754.7
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		$ 3,320.7				$ 3,894.0				$ 3,320.7	$ 3,894.0	$ 2,754.7

[1] 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.