Derivative Instruments, Hedging Activities and Fair Value Measurements, Nonrecurring Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	$ 63.4	$ 27.8	$ 8.4
Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	2.6
Carrying value prior to impairment	4.8
Long-lived Assets Held and Used [Member] | Spare Parts Inventory [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges		11.1
Carrying value prior to impairment		13.8
Long-lived Assets Disposed of By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	4.3
Long-lived Assets Disposed of Other Than By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	56.5	16.4
Long-lived Assets Disposed of Other Than By Sale [Member] | Texas Intrastate System [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	29.2	5.1	3.7
Long-lived Assets Disposed of Other Than By Sale [Member] | Texas Crude Oil Pipelines [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	10.6
Long-lived Assets Disposed of Other Than By Sale [Member] | Hobbs Facility [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges			2.6
Long-lived Assets Disposed of Other Than By Sale [Member] | Underground and other storage facilities [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges		9.1
Long-lived Assets Disposed of Other Than By Sale [Member] | Yscloskey Natural Gas Processing Plant [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	5.7
NGL Pipelines and Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	16.3	11.3	2.8
Onshore Natural Gas Pipelines And Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	29.2	10.4	5.2
Onshore Crude Oil Pipelines and Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	10.6	0	0
Offshore Pipelines And Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	4.0	5.5	0
Petrochemical and Refined Products Services [Member]
Assets, Fair Value Disclosure [Abstract]
Non-cash asset impairment charges	3.3	0.6	0.4
Fair Value, Measurements, Nonrecurring [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	2.2
Fair Value, Measurements, Nonrecurring [Member] | Long-lived Assets Disposed of By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0
Fair Value, Measurements, Nonrecurring [Member] | Long-lived Assets Disposed of Other Than By Sale [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	0.8
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	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	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
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	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
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
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Long-lived Assets Held and Used [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value	2.2
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Long-lived Assets Held and Used [Member] | Spare Parts Inventory [Member]
Assets, Fair Value Disclosure [Abstract]
Assets, fair value		2.7
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
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	$ 0.8