Intangible Assets and Goodwill, Intangible Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Identifiable intangible assets [Abstract]
Gross Value		$ 5,273.0	$ 5,548.4
Accumulated Amortization		(1,235.8)	(1,246.3)
Carrying Value		4,037.2	4,302.1	$ 1,462.2
Amortization Expense		174.1	110.6	105.6
Forecasted amortization expense [Abstract]
2016		181.6
2017		177.4
2018		171.6
2019		167.0
2020		166.3
Customer relationship intangibles [Member]
Identifiable intangible assets [Abstract]
Carrying Value		3,590.0
Contract-based intangibles [Member]
Identifiable intangible assets [Abstract]
Carrying Value		450.2
Incentive distribution rights [Member]
Identifiable intangible assets [Abstract]
Carrying Value			1,460.0
NGL Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value		730.4	1,051.1
Accumulated Amortization		(350.1)	(361.9)
Carrying Value		380.3	689.2
Amortization Expense		33.6	33.1	36.4
NGL Pipelines & Services [Member] | Customer relationship intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		447.4	340.8
Accumulated Amortization		(156.9)	(183.2)
Carrying Value		290.5	157.6
NGL Pipelines & Services [Member] | Contract-based intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		283.0	277.7
Accumulated Amortization		(193.2)	(178.7)
Carrying Value		89.8	99.0
NGL Pipelines & Services [Member] | Incentive distribution rights [Member]
Identifiable intangible assets [Abstract]
Gross Value	[1]	0.0	432.6
Accumulated Amortization	[1]	0.0	0.0
Carrying Value	[1]	0.0	432.6
Crude Oil Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value		2,485.8	2,244.8
Accumulated Amortization		(108.3)	(21.2)
Carrying Value		2,377.5	2,223.6
Amortization Expense		87.1	15.7	1.4
Crude Oil Pipelines & Services [Member] | Customer relationship intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		2,204.4	1,108.0
Accumulated Amortization		(39.1)	(7.7)
Carrying Value		2,165.3	1,100.3
Crude Oil Pipelines & Services [Member] | Contract-based intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		281.4	281.4
Accumulated Amortization		(69.2)	(13.5)
Carrying Value		212.2	267.9
Crude Oil Pipelines & Services [Member] | Incentive distribution rights [Member]
Identifiable intangible assets [Abstract]
Gross Value	[1]	0.0	855.4
Accumulated Amortization	[1]	0.0	0.0
Carrying Value	[1]	0.0	855.4
Natural Gas Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value		1,815.0	1,629.6
Accumulated Amortization		(727.3)	(656.7)
Carrying Value		1,087.7	972.9
Amortization Expense		40.0	45.0	50.1
Natural Gas Pipelines & Services [Member] | Customer relationship intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		1,350.3	1,163.6
Accumulated Amortization		(366.3)	(308.9)
Carrying Value		984.0	854.7
Natural Gas Pipelines & Services [Member] | Contract-based intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		464.7	466.0
Accumulated Amortization		(361.0)	(347.8)
Carrying Value		103.7	118.2
Petrochemical & Refined Products Services [Member]
Identifiable intangible assets [Abstract]
Gross Value		241.8	425.9
Accumulated Amortization		(50.1)	(51.1)
Carrying Value		191.7	374.8
Amortization Expense		8.9	6.9	6.2
Petrochemical & Refined Products Services [Member] | Customer relationship intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		185.5	198.4
Accumulated Amortization		(38.3)	(43.3)
Carrying Value		147.2	155.1
Petrochemical & Refined Products Services [Member] | Contract-based intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value		56.3	56.3
Accumulated Amortization		(11.8)	(7.8)
Carrying Value		44.5	48.5
Petrochemical & Refined Products Services [Member] | Incentive distribution rights [Member]
Identifiable intangible assets [Abstract]
Gross Value	[1]	0.0	171.2
Accumulated Amortization	[1]	0.0	0.0
Carrying Value	[1]	0.0	171.2
Offshore Pipelines & Services [Member]
Identifiable intangible assets [Abstract]
Gross Value	[2]	0.0	197.0
Accumulated Amortization	[2]	0.0	(155.4)
Carrying Value	[2]	0.0	41.6
Amortization Expense		4.5	9.9	$ 11.5
Offshore Pipelines & Services [Member] | Customer relationship intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value	[2]	0.0	195.8
Accumulated Amortization	[2]	0.0	(154.9)
Carrying Value	[2]	0.0	40.9
Offshore Pipelines & Services [Member] | Contract-based intangibles [Member]
Identifiable intangible assets [Abstract]
Gross Value	[2]	0.0	1.2
Accumulated Amortization	[2]	0.0	(0.5)
Carrying Value	[2]	$ 0.0	$ 0.7

[1] We recorded intangible assets having an aggregate carrying value of $1.46 billion in connection with our October 2014 acquisition of the IDRs of Oiltanking. The IDRs represented contractual rights to future cash incentive distributions to be paid by Oiltanking. These rights were granted to Oiltanking GP under the terms of Oiltanking's partnership agreement. Oiltanking GP could separate and sell the IDRs independent of its other residual general partner interest in Oiltanking. In February 2015 (following completion of Step 2 of the Oiltanking acquisition), the Oiltanking IDRs were cancelled and the carrying value of this intangible asset was reclassified to goodwill.

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