Business Segments, Segment Reporting Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012	Dec. 31, 2012
Information by business segment [Abstract]
Revenues from third parties	$ 11,377.2		$ 11,221.7
Revenues from related parties	5.9		30.8
Intersegment and intrasegment revenues	0		0
Total revenues	11,383.1		11,252.5
Equity in income (loss) of unconsolidated affiliates	44.5		9.9
Gross operating margin	1,231.1		1,052.7
Property, plant and equipment, net (see Note 6)	25,222.5			24,846.4
Investments in unconsolidated affiliates (see Note 7)	1,679.0			1,394.6
Intangible assets, net: (see Note 8)	1,539.8			1,566.8
Goodwill: (see Note 8)	2,086.1	[1]		2,086.8	[1]
Segment assets	30,527.4			29,894.6
NGL Pipelines and Services [Member]
Information by business segment [Abstract]
Revenues from third parties	3,950.7		4,354.1
Revenues from related parties	0.3		0.4
Intersegment and intrasegment revenues	2,709.0		2,818.2
Total revenues	6,660.0		7,172.7
Equity in income (loss) of unconsolidated affiliates	3.9		5.2
Gross operating margin	592.5		654.9
Property, plant and equipment, net (see Note 6)	9,059.1			8,494.8
Investments in unconsolidated affiliates (see Note 7)	412.1			324.6
Intangible assets, net: (see Note 8)	311.0			320.6
Goodwill: (see Note 8)	341.2			341.2
Segment assets	10,123.4			9,481.2
Onshore Natural Gas Pipelines And Services [Member]
Information by business segment [Abstract]
Revenues from third parties	874.2		804.9
Revenues from related parties	3.5		28.7
Intersegment and intrasegment revenues	256.2		223.7
Total revenues	1,133.9		1,057.3
Equity in income (loss) of unconsolidated affiliates	1.0		1.4
Gross operating margin	190.8		206.2
Property, plant and equipment, net (see Note 6)	8,942.0			8,950.1
Investments in unconsolidated affiliates (see Note 7)	24.6			24.9
Intangible assets, net: (see Note 8)	1,055.5			1,067.9
Goodwill: (see Note 8)	296.3			296.3
Segment assets	10,318.4			10,339.2
Onshore Crude Oil Pipelines and Services [Member]
Information by business segment [Abstract]
Revenues from third parties	4,793.2		4,473.6
Revenues from related parties	0		0
Intersegment and intrasegment revenues	2,024.7		1,730.9
Total revenues	6,817.9		6,204.5
Equity in income (loss) of unconsolidated affiliates	36.6		0.5
Gross operating margin	236.4		39.3
Property, plant and equipment, net (see Note 6)	1,359.0			1,385.9
Investments in unconsolidated affiliates (see Note 7)	660.3			493.8
Intangible assets, net: (see Note 8)	5.6			5.9
Goodwill: (see Note 8)	311.2			311.2
Segment assets	2,336.1			2,196.8
Offshore Pipelines And Services [Member]
Information by business segment [Abstract]
Revenues from third parties	40.5		54.4
Revenues from related parties	2.1		1.7
Intersegment and intrasegment revenues	2.0		3.3
Total revenues	44.6		59.4
Equity in income (loss) of unconsolidated affiliates	6.4		6.9
Gross operating margin	40.5		52.1
Property, plant and equipment, net (see Note 6)	1,323.5			1,343.0
Investments in unconsolidated affiliates (see Note 7)	509.0			479.0
Intangible assets, net: (see Note 8)	63.1			66.2
Goodwill: (see Note 8)	82.1			82.1
Segment assets	1,977.7			1,970.3
Petrochemical and Refined Products Services [Member]
Information by business segment [Abstract]
Revenues from third parties	1,718.6		1,534.7
Revenues from related parties	0		0
Intersegment and intrasegment revenues	422.1		439.9
Total revenues	2,140.7		1,974.6
Equity in income (loss) of unconsolidated affiliates	(3.4)		(6.5)
Gross operating margin	170.9		97.8
Property, plant and equipment, net (see Note 6)	2,548.4			2,559.5
Investments in unconsolidated affiliates (see Note 7)	73.0			72.3
Intangible assets, net: (see Note 8)	104.6			106.2
Goodwill: (see Note 8)	1,055.3			1,056.0
Segment assets	3,781.3			3,794.0
Other Investment [Member]
Information by business segment [Abstract]
Revenues from third parties	0		0
Revenues from related parties	0		0
Intersegment and intrasegment revenues	0		0
Total revenues	0		0
Equity in income (loss) of unconsolidated affiliates	0		2.4
Gross operating margin	0		2.4
Property, plant and equipment, net (see Note 6)	0			0
Investments in unconsolidated affiliates (see Note 7)	0			0
Intangible assets, net: (see Note 8)	0			0
Goodwill: (see Note 8)	0			0
Segment assets	0			0
Adjustments and Eliminations [Member]
Information by business segment [Abstract]
Revenues from third parties	0		0
Revenues from related parties	0		0
Intersegment and intrasegment revenues	(5,414.0)		(5,216.0)
Total revenues	(5,414.0)		(5,216.0)
Equity in income (loss) of unconsolidated affiliates	0		0
Gross operating margin	0		0
Property, plant and equipment, net (see Note 6)	1,990.5			2,113.1
Investments in unconsolidated affiliates (see Note 7)	0			0
Intangible assets, net: (see Note 8)	0			0
Goodwill: (see Note 8)	0			0
Segment assets	$ 1,990.5			$ 2,113.1

[1] The total carrying amount of goodwill at March 31, 2013 and December 31, 2012 is net of $1.3 million of accumulated impairment charges. No goodwill impairment charges were recorded during the three months ended March 31, 2013.