Business Segments, Segment Reporting Information (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Information by business segment [Abstract]
Revenues from third parties										$ 26,955.6	$ 47,879.7	$ 47,661.1
Revenues from related parties										72.3	71.5	65.9
Intersegment and intrasegment revenues										0.0	0.0	0.0
Total revenues		$ 6,155.0	$ 6,307.9	$ 7,092.5	$ 7,472.5	$ 10,190.3	$ 12,330.2	$ 12,520.8	$ 12,909.9	27,027.9	47,951.2	47,727.0
Equity in income (loss) of unconsolidated affiliates										373.6	259.5	167.3
Gross operating margin										5,332.1	5,286.5	4,818.1
Property, plant and equipment, net		32,034.7				29,881.6				32,034.7	29,881.6	26,946.6
Investments in unconsolidated affiliates		2,628.5				3,042.0				2,628.5	3,042.0	2,437.1
Intangible assets, net		4,037.2				4,302.1				4,037.2	4,302.1	1,462.2
Goodwill		5,745.2				4,300.2				5,745.2	4,300.2	2,080.0	$ 2,086.8
Segment assets		44,445.6				41,525.9				44,445.6	41,525.9	32,925.9
NGL Pipelines and Services [Member]
Information by business segment [Abstract]
Total revenues										9,788.0	17,089.8	17,120.2
Equity in income (loss) of unconsolidated affiliates										57.5	30.6	15.7
Intangible assets, net		380.3				689.2				380.3	689.2
Goodwill		2,651.7				2,210.2				2,651.7	2,210.2	341.2	341.2
Crude Oil Pipelines & Services [Member]
Information by business segment [Abstract]
Total revenues										10,305.9	20,184.3	20,650.4
Equity in income (loss) of unconsolidated affiliates										281.4	184.6	140.3
Intangible assets, net		2,377.5				2,223.6				2,377.5	2,223.6
Goodwill		1,841.0				918.7				1,841.0	918.7	305.1	311.2
Natural Gas Pipelines & Services [Member]
Information by business segment [Abstract]
Total revenues										2,743.3	4,203.8	3,538.5
Equity in income (loss) of unconsolidated affiliates										3.8	3.6	3.8
Intangible assets, net		1,087.7				972.9				1,087.7	972.9
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										4,111.9	6,316.5	6,258.5
Equity in income (loss) of unconsolidated affiliates	[1]									(15.7)	(13.3)	(22.3)
Intangible assets, net		191.7				374.8				191.7	374.8
Goodwill		956.2				793.0				956.2	793.0	1,055.3	1,056.0
Offshore Pipelines And Services [Member]
Information by business segment [Abstract]
Total revenues										78.8	156.8	159.4
Equity in income (loss) of unconsolidated affiliates										46.6	54.0	29.8
Intangible assets, net	[2]	0.0				41.6				0.0	41.6
Goodwill		0.0				82.0				0.0	82.0	82.1	$ 82.1
Reportable Business Segments [Member] | NGL Pipelines and Services [Member]
Information by business segment [Abstract]
Revenues from third parties										9,779.0	17,078.4	17,119.1
Revenues from related parties										9.0	11.4	1.1
Intersegment and intrasegment revenues										10,217.9	13,716.5	11,096.6
Total revenues										20,005.9	30,806.3	28,216.8
Equity in income (loss) of unconsolidated affiliates										57.5	30.6	15.7
Gross operating margin										2,771.6	2,877.7	2,514.4
Property, plant and equipment, net		12,909.7				11,766.9				12,909.7	11,766.9	9,957.8
Investments in unconsolidated affiliates		718.7				682.3				718.7	682.3	645.5
Intangible assets, net		380.3				689.2				380.3	689.2	285.2
Goodwill		2,651.7				2,210.2				2,651.7	2,210.2	341.2
Segment assets		16,660.4				15,348.6				16,660.4	15,348.6	11,229.7
Reportable Business Segments [Member] | Crude Oil Pipelines & Services [Member]
Information by business segment [Abstract]
Revenues from third parties										10,258.3	20,151.9	20,609.1
Revenues from related parties										47.6	32.4	41.3
Intersegment and intrasegment revenues										5,162.0	12,678.7	10,222.3
Total revenues										15,467.9	32,863.0	30,872.7
Equity in income (loss) of unconsolidated affiliates										281.4	184.6	140.3
Gross operating margin										961.9	762.5	742.7
Property, plant and equipment, net		3,550.3				2,332.2				3,550.3	2,332.2	1,479.9
Investments in unconsolidated affiliates		1,813.4				1,767.7				1,813.4	1,767.7	1,165.2
Intangible assets, net		2,377.5				2,223.6				2,377.5	2,223.6	4.5
Goodwill		1,841.0				918.7				1,841.0	918.7	305.1
Segment assets		9,582.2				7,242.2				9,582.2	7,242.2	2,954.7
Reportable Business Segments [Member] | Natural Gas Pipelines & Services [Member]
Information by business segment [Abstract]
Revenues from third parties										2,729.5	4,182.6	3,522.7
Revenues from related parties										13.8	21.2	15.8
Intersegment and intrasegment revenues										662.1	1,106.7	959.7
Total revenues										3,405.4	5,310.5	4,498.2
Equity in income (loss) of unconsolidated affiliates										3.8	3.6	3.8
Gross operating margin										782.6	803.3	789.0
Property, plant and equipment, net		8,620.0				8,835.5				8,620.0	8,835.5	8,917.3
Investments in unconsolidated affiliates		22.5				23.2				22.5	23.2	24.2
Intangible assets, net		1,087.7				972.9				1,087.7	972.9	1,017.8
Goodwill		296.3				296.3				296.3	296.3	296.3
Segment assets		10,026.5				10,127.9				10,026.5	10,127.9	10,255.6
Reportable Business Segments [Member] | Petrochemical & Refined Products Services [Member]
Information by business segment [Abstract]
Revenues from third parties										4,111.9	6,316.5	6,258.5
Revenues from related parties										0.0	0.0	0.0
Intersegment and intrasegment revenues										1,126.0	1,779.6	1,764.0
Total revenues										5,237.9	8,096.1	8,022.5
Equity in income (loss) of unconsolidated affiliates										(15.7)	(13.3)	(22.3)
Gross operating margin										718.5	681.0	625.9
Property, plant and equipment, net		3,060.7				3,047.2				3,060.7	3,047.2	2,712.4
Investments in unconsolidated affiliates		73.9				75.1				73.9	75.1	70.4
Intangible assets, net		191.7				374.8				191.7	374.8	100.0
Goodwill		956.2				793.0				956.2	793.0	1,055.3
Segment assets		4,282.5				4,290.1				4,282.5	4,290.1	3,938.1
Reportable Business Segments [Member] | Offshore Pipelines And Services [Member]
Information by business segment [Abstract]
Revenues from third parties										76.9	150.3	151.7
Revenues from related parties										1.9	6.5	7.7
Intersegment and intrasegment revenues										0.6	6.5	9.6
Total revenues										79.4	163.3	169.0
Equity in income (loss) of unconsolidated affiliates										46.6	54.0	29.8
Gross operating margin										97.5	162.0	146.1
Property, plant and equipment, net		0.0				1,145.1				0.0	1,145.1	1,223.7
Investments in unconsolidated affiliates		0.0				493.7				0.0	493.7	531.8
Intangible assets, net		0.0				41.6				0.0	41.6	54.7
Goodwill		0.0				82.0				0.0	82.0	82.1
Segment assets		0.0				1,762.4				0.0	1,762.4	1,892.3
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										(17,168.6)	(29,288.0)	(24,052.2)
Total revenues										(17,168.6)	(29,288.0)	(24,052.2)
Equity in income (loss) of unconsolidated affiliates										0.0	0.0	0.0
Gross operating margin										0.0	0.0	0.0
Property, plant and equipment, net		3,894.0				2,754.7				3,894.0	2,754.7	2,655.5
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		$ 3,894.0				$ 2,754.7				$ 3,894.0	$ 2,754.7	$ 2,655.5

[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 the market and income approaches, indicate that the fair value of this investment remains substantially in excess of its carrying value.

[2] Our intangible assets classified within the Offshore Pipelines & Services segment were sold to Genesis in July 2015 (see Note 5).