Net Income Per Class A Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Basic and Diluted Net Income per Class A Share
Net income attributable to PAGP	$ 22	$ 70
AAP Units
Net Income Per Class A Share
Antidilutive securities excluded from computation of earnings per share (shares)	47	51
AAP Management Units | Maximum
Net Income Per Class A Share
Antidilutive securities excluded from computation of earnings per share (shares)	1	1
Class A Shares
Basic and Diluted Net Income per Class A Share
Basic weighted average Class A shares outstanding (shares)	194	194
Diluted weighted average Class A shares outstanding (shares)	194	194
Basic net income per Class A share (usd per share)	$ 0.11	$ 0.36
Diluted net income per Class A share (usd per share)	$ 0.11	$ 0.36