Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total revenues	$ 7,605	$ 5,873	$ 6,078	$ 6,667	$ 5,952	$ 5,170	$ 4,950	$ 4,111	$ 26,223	$ 20,182	$ 23,152
Gross margin	327	112	325	665	286	419	219	349	1,429	1,273
Operating income	261	44	257	591	218	349	146	282	1,153	994	1,262
Net income	191	34	189	444	127	298	102	203	858	730	906
Net income attributable to PAA	$ 191	$ 33	$ 188	$ 444	$ 126	$ 297	$ 101	$ 202	$ 856	$ 726	$ 903
Cash distributions per common unit (in dollars per unit)	$ 0.30	$ 0.55	$ 0.55	$ 0.55	$ 0.55	$ 0.70	$ 0.70	$ 0.70	$ 1.95	$ 2.65
Common Units
Basic net income/(loss) per common unit (in dollars per unit)	0.19	(0.01)	0.21	0.59	0.14	0.40	(0.20)	0.07	0.96	0.43	$ 0.78
Diluted net income/(loss) per common unit (in dollars per unit)	$ 0.19	$ (0.01)	$ 0.21	$ 0.58	$ 0.14	$ 0.40	$ (0.20)	$ 0.07	$ 0.95	$ 0.43	$ 0.77

Total revenues less purchases and related costs, field operating costs and depreciation and amortization.

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Cash dividends declared or paid to each outstanding limited partnership unit during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Per unit of ownership amount after tax of income (loss) available to limited partnership (LP) unit-holder and units that would have been outstanding assuming the issuance of limited partner units for dilutive potential units outstanding.

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Per unit of ownership amount after tax of income (loss) available to outstanding limited partnership (LP) unit-holder.

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The net result for the period of deducting operating expenses from operating revenues.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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