Net Income Per Limited Partner Unit (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Basic and Diluted Net Income Per Limited Partner Unit
General partner ownership interest (as a percent)	2.00%	2.00%	2.00%	2.00%
Numerator for Basic and Diluted Net Income per Limited Partner Unit:
Net income attributable to Plains	$ 231	$ 165	$ 1,052	$ 774
Net income available to limited partners	133	89	764	554
Denominator for Basic and Diluted Net Income per Limited Partner Unit:
Basic weighted average number of limited partner units outstanding (in units)	343	329	340	322
Effect of dilutive securities:
Weighted average LTIP units (in units)	2	2	2	3
Diluted weighted average number of limited partner units outstanding (in units)	345	331	342	325
Basic and Diluted Net Income per Limited Partner Unit
Basic net income per limited partner unit (in dollars per unit)	$ 0.38	$ 0.27	$ 2.23	$ 1.71
Diluted net income per limited partner unit (in dollars per unit)	$ 0.38	$ 0.27	$ 2.22	$ 1.70
Basic Net Income Per Limited Partner Unit
Numerator for Basic and Diluted Net Income per Limited Partner Unit:
Net income attributable to Plains	231	165	1,052	774
General partner's incentive distribution	(95)	(74)	(272)	(208)
General partner 2% ownership	(3)	(2)	(16)	(12)
Net income available to limited partners	133	89	764	554
Undistributed earnings allocated and distributions to participating securities	(1)	(1)	(5)	(3)
Net income available to limited partners in accordance with the application of the two-class method for MLPs	132	88	759	551
Diluted Net Income Per Limited Partner Unit
Numerator for Basic and Diluted Net Income per Limited Partner Unit:
Net income attributable to Plains	231	165	1,052	774
General partner's incentive distribution	(95)	(74)	(272)	(208)
General partner 2% ownership	(3)	(2)	(16)	(12)
Net income available to limited partners	133	89	764	554
Undistributed earnings allocated and distributions to participating securities	(1)	(1)	(4)	(3)
Net income available to limited partners in accordance with the application of the two-class method for MLPs	$ 132	$ 88	$ 760	$ 551