Intangible Assets and Goodwill, Goodwill (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013		Dec. 31, 2012
Changes in carrying amount of goodwill [Roll Forward]
Balance at beginning of period	$ 2,086.8	[1]
Goodwill related to the sale of assets	(6.8)
Balance at end of period	2,080.0	[1]
Accumulated impairment charges	1.3		1.3
NGL Pipelines & Services [Member]
Changes in carrying amount of goodwill [Roll Forward]
Balance at beginning of period	341.2	[1]
Goodwill related to the sale of assets	0
Balance at end of period	341.2	[1]
Onshore Natural Gas Pipelines & Services [Member]
Changes in carrying amount of goodwill [Roll Forward]
Balance at beginning of period	296.3	[1]
Goodwill related to the sale of assets	0
Balance at end of period	296.3	[1]
Onshore Crude Oil Pipelines & Services [Member]
Changes in carrying amount of goodwill [Roll Forward]
Balance at beginning of period	311.2	[1]
Goodwill related to the sale of assets	(6.1)
Balance at end of period	305.1	[1]
Offshore Pipelines & Services [Member]
Changes in carrying amount of goodwill [Roll Forward]
Balance at beginning of period	82.1	[1]
Goodwill related to the sale of assets	0
Balance at end of period	82.1	[1]
Petrochemical & Refined Products Services [Member]
Changes in carrying amount of goodwill [Roll Forward]
Balance at beginning of period	1,056.0	[1]
Goodwill related to the sale of assets	(0.7)
Balance at end of period	$ 1,055.3	[1]

[1] The total carrying amount of goodwill at September 30, 2013 and December 31, 2012 is net of $1.3 million of accumulated impairment charges. No goodwill impairment charges were recorded during the nine months ended September 30, 2013.