Net Income Per Class A Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Basic and Diluted Net Income per Class A Share
Net income attributable to PAGP	$ 48	$ 31	$ 117	$ 53
AAP Units
Basic and Diluted Net Income Per Share
Antidilutive securities excluded from computation of earnings per share (shares)	46	47	46	47
Class A Shares
Basic and Diluted Net Income per Class A Share
Basic weighted average Class A shares outstanding (shares)	195	194	195	194
Diluted weighted average Class A shares outstanding (shares)	195	194	195	194
Basic net income per Class A share (usd per share)	$ 0.25	$ 0.16	$ 0.60	$ 0.27
Diluted net income per Class A share (usd per share)	$ 0.25	$ 0.16	$ 0.60	$ 0.27