Acquisitions, Divestitures and Other Transactions - Pro Forma (Details) - Plains Oryx Permian Basin LLC - Oryx Midstream Holdings LLC - Joint Venture Formation $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) $ / shares
Business Acquisition [Line Items]
Total revenues | $	$ 42,359
Net income attributable to PAGP | $	$ 37
Class A Shares
Business Acquisition [Line Items]
Basic net income per Class A Share (in dollars per share) | $ / shares	$ 0.19
Diluted net income per Class A Share (in dollars per share) | $ / shares	$ 0.19