Acquisitions (Details) (USD $)	1 Months Ended		3 Months Ended		9 Months Ended
	Apr. 30, 2012	Mar. 31, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Apr. 02, 2012 barrel bcfperday plant mi barrelperday railcar
BP NGL Acquisition
Business acquisition
Interest acquried (as a percent)							100.00%
Aggregate purchase price							$ 1,680,000,000
Imputed interest							17,000,000
Contractual rights related to NGL pipelines acquired (in miles)							2,600
NGL storage capacity acquired (in barrels)							20,000,000
Number of fractionation plants acquired							7
Aggregate net capacity of fractionation plants acquired (in barrels per day)							232,000
Number of straddle plants acquired							4
Number of field gas processing plants acquired							2
Aggregate capacity of straddle and field gas processing plants acquired (in Bcf per day)							6
Long-term and seasonal NGL inventories acquired (in barrels)							8,000,000
Throughput capacity of third-party straddle plant long-term contract acquired (in Bcf per day)							2.5
Number of rail cars under long-term leases acquired							720
Period of sourcing services for gas supply will be provided after acquisition	2 years
Business acquisition, preliminary allocation of fair value of assets and liabilities
Working capital							253,000,000
Property and equipment							1,067,000,000
Linefill							84,000,000
Long-term inventory							166,000,000
Intangible assets (contract)							132,000,000
Goodwill							233,000,000
Deferred tax liability							(233,000,000)
Environmental liability							(14,000,000)
Other long-term liabilities							(5,000,000)
Total net assets due to assets acquired			1,683,000,000		1,683,000,000		1,683,000,000
Total assets due to assets acquired			2,461,000,000		2,461,000,000
Net proceeds from issuance of common units and senior notes		1,690,000,000
Acquisition-related costs			13,000,000		13,000,000
Intangible assets, useful life
Average Depreciable Life	13 years
Estimated amortization expense for the five full or partial calendar years
2012			39,000,000		39,000,000
2013			30,000,000		30,000,000
2014			10,000,000		10,000,000
2015			8,000,000		8,000,000
2016			7,000,000		7,000,000
2017			6,000,000		6,000,000
Supplemental pro forma:
Pro Forma, Total revenues			9,354,000,000	9,185,000,000	29,182,000,000	27,726,000,000
Pro forma, Net income attributable to Plains			165,000,000	333,000,000	772,000,000	836,000,000
Limited partner interest in net income attributable to Plains			89,000,000	276,000,000	556,000,000	675,000,000
Pro forma, Basic (in dollars per unit)			$ 0.27	$ 0.89	$ 1.70	$ 2.21
Pro forma, Diluted (in dollars per unit)			$ 0.27	$ 0.88	$ 1.69	$ 2.20
BP NGL Acquisition | Transportation
Business acquisition, preliminary allocation of fair value of assets and liabilities
Total net assets due to assets acquired			398,000,000		398,000,000
Total assets due to assets acquired			555,000,000		555,000,000
BP NGL Acquisition | Facilities
Business acquisition, preliminary allocation of fair value of assets and liabilities
Total net assets due to assets acquired			787,000,000		787,000,000
Total assets due to assets acquired			1,061,000,000		1,061,000,000
BP NGL Acquisition | Supply and Logistics
Business acquisition, preliminary allocation of fair value of assets and liabilities
Total net assets due to assets acquired			498,000,000		498,000,000
Total assets due to assets acquired			845,000,000		845,000,000
BP NGL Acquisition | Minimum
Property and equipment, useful life
Average Depreciable Life	5 years
BP NGL Acquisition | Maximum
Property and equipment, useful life
Average Depreciable Life	70 years
Other Acquisitions
Business acquisition
Aggregate purchase price			25,000,000		25,000,000
Business acquisition, preliminary allocation of fair value of assets and liabilities
Goodwill			$ 10,000,000		$ 10,000,000