Derivative Instruments, Hedging Activities and Fair Value Measurements, Nonrecurring Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	$ 15.2		$ 43.1		$ 53.3		$ 57.6
Long-lived Assets Disposed of Other Than By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges					43.3	[1]	50.7	[2]
Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges					4.2		2.6
Long-lived Assets Disposed of By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges					5.8		4.3
Fair Value, Measurements, Nonrecurring [Member] | Long-lived Assets Disposed of Other Than By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0	[1]	0	[2]	0	[1]	0	[2]
Fair Value, Measurements, Nonrecurring [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	6.1		2.2		6.1		2.2
Fair Value, Measurements, Nonrecurring [Member] | Long-lived Assets Disposed of By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	11.7		0		11.7		0
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | Long-lived Assets Disposed of Other Than By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0	[1]	0	[2]	0	[1]	0	[2]
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0		0		0		0
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | Long-lived Assets Disposed of By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	11.7		0		11.7		0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | Long-lived Assets Disposed of Other Than By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0	[1]	0	[2]	0	[1]	0	[2]
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0		0		0		0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | Long-lived Assets Disposed of By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0		0		0		0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Long-lived Assets Disposed of Other Than By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0	[1]	0	[2]	0	[1]	0	[2]
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	6.1		2.2		6.1		2.2
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Long-lived Assets Disposed of By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0		0		0		0
NGL Pipelines and Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	0.3		8.3		10.0		16.3
Onshore Natural Gas Pipelines And Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	0		29.2		0		29.2
Onshore Crude Oil Pipelines and Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	0		0		16.6		6.2
Offshore Pipelines And Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	13.2		4.0		13.2		4.0
Petrochemical and Refined Products Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	$ 1.7		$ 1.6		$ 13.5		$ 1.9

[1] Our non-cash asset impairment charges for the nine months ended September 30, 2013 primarily represent the abandonment of crude oil and natural gas pipeline segments in Texas, Oklahoma and the Gulf of Mexico, certain refined products terminal assets in Texas, and an NGL storage cavern in Arizona.

[2] Our non-cash asset impairment charges for the nine months ended September 30, 2012 primarily represent the abandonment of crude oil and natural gas pipeline segments in Texas and the Gulf of Mexico.