Intangible Assets and Goodwill, Significant Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Identifiable intangible assets [Abstract]
Gross Value	5,548.4	$ 2,612.2
Accumulated Amortization	(1,246.3)	(1,150.0)
Carrying Value	4,302.1	1,462.2	1,566.8
NGL Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	1,051.1	622.1
Accumulated Amortization	(361.9)	(336.9)
Carrying Value	689.2	285.2
Onshore Natural Gas Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	1,629.6	1,629.7
Accumulated Amortization	(656.7)	(611.9)
Carrying Value	972.9	1,017.8
Onshore Crude Oil Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	2,244.8	11.1
Accumulated Amortization	(21.2)	(6.6)
Carrying Value	2,223.6	4.5
Petrochemical & Refined Products Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	425.9	144.2
Accumulated Amortization	(51.1)	(44.2)
Carrying Value	374.8	100.0
Customer relationship intangibles [Member]
Identifiable intangible assets [Abstract]
Carrying Value	2,310.0
Customer relationship intangibles [Member] | NGL Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	340.8	340.8
Accumulated Amortization	(183.2)	(165.7)
Carrying Value	157.6	175.1
Customer relationship intangibles [Member] | Onshore Natural Gas Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	1,163.6	1,163.6
Accumulated Amortization	(308.9)	(281.2)
Carrying Value	854.7	882.4
Customer relationship intangibles [Member] | Onshore Crude Oil Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	1,108.0	10.7
Accumulated Amortization	(7.7)	(6.3)
Carrying Value	1,100.3	4.4
Customer relationship intangibles [Member] | Petrochemical & Refined Products Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	198.4	104.3
Accumulated Amortization	(43.3)	(38.2)
Carrying Value	155.1	66.1
Customer relationship intangibles [Member] | State Line Gathering [Member]
Identifiable intangible assets [Abstract]
Finite-Lived Intangible Asset, Useful Life	37 years
Customer relationship intangibles [Member] | State Line Gathering [Member] | Onshore Natural Gas Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	675.0
Accumulated Amortization	(68.7)
Carrying Value	606.3
Customer relationship intangibles [Member] | Fairplay Gathering [Member]
Identifiable intangible assets [Abstract]
Finite-Lived Intangible Asset, Useful Life	23 years
Customer relationship intangibles [Member] | Fairplay Gathering [Member] | Onshore Natural Gas Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	116.6
Accumulated Amortization	(30.7)
Carrying Value	85.9
Customer relationship intangibles [Member] | Fairplay Processing [Member]
Identifiable intangible assets [Abstract]
Finite-Lived Intangible Asset, Useful Life	23 years
Customer relationship intangibles [Member] | Fairplay Processing [Member] | NGL Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	103.4
Accumulated Amortization	(27.2)
Carrying Value	76.2
Customer relationship intangibles [Member] | State Line and Fairplay [Member]
Identifiable intangible assets [Abstract]
Gross Value	895.0
Accumulated Amortization	(126.6)
Carrying Value	768.4
Customer relationship intangibles [Member] | San Juan Gathering [Member]
Identifiable intangible assets [Abstract]
Carrying Value	146.9
Finite-Lived Intangible Asset, Useful Life	35 years
Customer relationship intangibles [Member] | Offshore Pipelines and Platforms [Member]
Identifiable intangible assets [Abstract]
Carrying Value	40.9
Customer relationship intangibles [Member] | Offshore Pipelines and Platforms [Member] | Minimum [Member]
Identifiable intangible assets [Abstract]
Finite-Lived Intangible Asset, Useful Life	11 years
Customer relationship intangibles [Member] | Offshore Pipelines and Platforms [Member] | Maximum [Member]
Identifiable intangible assets [Abstract]
Finite-Lived Intangible Asset, Useful Life	33 years
Customer relationship intangibles [Member] | Encinal [Member]
Identifiable intangible assets [Abstract]
Carrying Value	50.2
Finite-Lived Intangible Asset, Useful Life	20 years
Customer relationship intangibles [Member] | Oiltanking Partners L.P. [Member]
Identifiable intangible assets [Abstract]
Gross Value	1,192.5
Accumulated Amortization	(1.4)
Carrying Value	1,191.1
Finite-Lived Intangible Asset, Useful Life	29 years
Customer relationship intangibles [Member] | Oiltanking Partners L.P. [Member] | Onshore Crude Oil Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	1,098.4
Accumulated Amortization	(1.4)
Carrying Value	1,097.0
Customer relationship intangibles [Member] | Oiltanking Partners L.P. [Member] | Petrochemical & Refined Products Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	94.1
Accumulated Amortization	0
Carrying Value	94.1
Contract-based intangibles [Member]
Identifiable intangible assets [Abstract]
Carrying Value	534.3
Contract-based intangibles [Member] | NGL Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	277.7	281.3
Accumulated Amortization	(178.7)	(171.2)
Carrying Value	99.0	110.1
Contract-based intangibles [Member] | Onshore Natural Gas Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	466.0	466.1
Accumulated Amortization	(347.8)	(330.7)
Carrying Value	118.2	135.4
Contract-based intangibles [Member] | Onshore Crude Oil Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	281.4	0.4
Accumulated Amortization	(13.5)	(0.3)
Carrying Value	267.9	0.1
Contract-based intangibles [Member] | Petrochemical & Refined Products Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	56.3	39.9
Accumulated Amortization	(7.8)	(6.0)
Carrying Value	48.5	33.9
Contract-based intangibles [Member] | San Juan Gathering [Member]
Identifiable intangible assets [Abstract]
Carrying Value	34.6
Finite-Lived Intangible Asset, Useful Life	20 years
Contract-based intangibles [Member] | Jonah Gas Gathering [Member]
Identifiable intangible assets [Abstract]
Carrying Value	82.8
Finite-Lived Intangible Asset, Useful Life	40 years
Contract-based intangibles [Member] | Shell Processing Agreement [Member]
Identifiable intangible assets [Abstract]
Carrying Value	50.6
Finite-Lived Intangible Asset, Useful Life	20 years
Contract-based intangibles [Member] | Oiltanking Partners L.P. [Member]
Identifiable intangible assets [Abstract]
Gross Value	297.4
Accumulated Amortization	(13.9)
Carrying Value	283.5
Finite-Lived Intangible Asset, Useful Life	6 years
Contract-based intangibles [Member] | Oiltanking Partners L.P. [Member] | Onshore Crude Oil Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	281.0
Accumulated Amortization	(13.2)
Carrying Value	267.8
Contract-based intangibles [Member] | Oiltanking Partners L.P. [Member] | Petrochemical & Refined Products Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	16.4
Accumulated Amortization	(0.7)
Carrying Value	15.7
Incentive distribution rights [Member]
Identifiable intangible assets [Abstract]
Carrying Value	1,460.0
Incentive distribution rights [Member] | NGL Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	432.6	0
Accumulated Amortization	0	0
Carrying Value	432.6	0
Incentive distribution rights [Member] | Onshore Crude Oil Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	855.4	0
Accumulated Amortization	0	0
Carrying Value	855.4	0
Incentive distribution rights [Member] | Petrochemical & Refined Products Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	171.2	0
Accumulated Amortization	0	0
Carrying Value	171.2	$ 0