CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income/(loss)	$ 600	$ (2,440)	$ 2,062
Other comprehensive income	65	15	97
Comprehensive income/(loss)	665	(2,425)	2,159
Comprehensive (income)/loss attributable to noncontrolling interests	(588)	1,863	(1,805)
Comprehensive income/(loss) attributable to PAGP	$ 77	$ (562)	$ 354