Investments in Unconsolidated Affiliates (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 3,064.9			$ 3,042.0
Equity in income (loss) of unconsolidated affiliates by business segment [Abstract]
Equity in income of unconsolidated affiliates	89.2		56.5
Unamortized excess cost amounts by business segment [Abstract]
Unamortized excess cost amounts	103.1			59.6
Equity method investment amortization of excess cost	2.6		0.7
NGL Pipelines & Services [Member]
Equity in income (loss) of unconsolidated affiliates by business segment [Abstract]
Equity in income of unconsolidated affiliates	11.6		1.4
Unamortized excess cost amounts by business segment [Abstract]
Unamortized excess cost amounts	26.2			26.5
Equity method investment amortization of excess cost	0.3		0.3
NGL Pipelines & Services [Member] | Venice Energy Service Company LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	13.10%
Investments in unconsolidated affiliates	27.0			27.7
NGL Pipelines & Services [Member] | K/D/S Promix, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	37.6			38.5
NGL Pipelines & Services [Member] | Baton Rouge Fractionators LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	32.20%
Investments in unconsolidated affiliates	18.6			18.8
NGL Pipelines & Services [Member] | Skelly-Belvieu Pipeline Company, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	39.5			40.1
NGL Pipelines & Services [Member] | Texas Express Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	35.00%
Investments in unconsolidated affiliates	349.6			349.3
NGL Pipelines & Services [Member] | Texas Express Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	45.00%
Investments in unconsolidated affiliates	37.6			37.9
NGL Pipelines & Services [Member] | Front Range Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	33.30%
Investments in unconsolidated affiliates	171.7			170.0
Onshore Natural Gas Pipelines & Services [Member]
Equity in income (loss) of unconsolidated affiliates by business segment [Abstract]
Equity in income of unconsolidated affiliates	0.9		0.9
Onshore Natural Gas Pipelines & Services [Member] | White River Hub, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	23.1			23.2
Onshore Crude Oil Pipelines & Services [Member]
Equity in income (loss) of unconsolidated affiliates by business segment [Abstract]
Equity in income of unconsolidated affiliates	59.9		42.7
Unamortized excess cost amounts by business segment [Abstract]
Unamortized excess cost amounts	21.4			21.7
Equity method investment amortization of excess cost	0.3		0.2
Onshore Crude Oil Pipelines & Services [Member] | Seaway Crude Pipeline Company LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	1,430.1			1,431.2
Onshore Crude Oil Pipelines & Services [Member] | Eagle Ford Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	350.5			336.5
Onshore Crude Oil Pipelines & Services [Member] | Eagle Ford Terminals Corpus Christi LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	17.3	[1]		0	[1]
Offshore Pipelines & Services [Member]
Equity in income (loss) of unconsolidated affiliates by business segment [Abstract]
Equity in income of unconsolidated affiliates	20.2		11.1
Unamortized excess cost amounts by business segment [Abstract]
Unamortized excess cost amounts	53.1			9.0
Equity method investment amortization of excess cost	2.0		0.2
Offshore Pipelines & Services [Member] | Poseidon Oil Pipeline Company, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	36.00%
Investments in unconsolidated affiliates	29.2			31.8
Offshore Pipelines & Services [Member] | Cameron Highway Oil Pipeline Company [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	198.1			201.3
Offshore Pipelines & Services [Member] | Deepwater Gateway LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	78.9			79.6
Offshore Pipelines & Services [Member] | Neptune Pipeline Company, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	25.70%
Investments in unconsolidated affiliates	33.7			34.9
Offshore Pipelines & Services [Member] | Southeast Keathley Canyon Pipeline Company, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	147.6			146.1
Petrochemical & Refined Products Services [Member]
Equity in income (loss) of unconsolidated affiliates by business segment [Abstract]
Equity in income of unconsolidated affiliates	(3.4)		0.4
Unamortized excess cost amounts by business segment [Abstract]
Unamortized excess cost amounts	2.4			2.4
Petrochemical & Refined Products Services [Member] | Baton Rouge Propylene Concentrator, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	30.00%
Investments in unconsolidated affiliates	6.1			6.5
Petrochemical & Refined Products Services [Member] | Centennial Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Interest (in hundredths)	50.00%
Investments in unconsolidated affiliates	66.3			66.1
Petrochemical & Refined Products Services [Member] | Other Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 2.4			$ 2.5

[1] New joint venture formed with Plains Marketing, L.P. in March 2015 to construct and operate a marine terminal that will handle crude oil delivered by Eagle Ford Pipeline LLC.