Net Income/(Loss) Per Class A Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Basic Net Income/(Loss) per Class A Share
Net income/(loss) attributable to PAGP	$ 168	$ 60	$ (568)
Diluted Net Income/(Loss) per Class A Share
Net income/(loss) attributable to PAGP	168	60	(568)
Incremental net income/(loss) attributable to PAGP resulting from assumed exchange of AAP units	0		(189)
Net income/(loss) attributable to PAGP including incremental net income/(loss) from assumed exchange of AAP units	$ 168	$ 60	$ (757)
AAP Units
Basic and diluted earnings per share
Antidilutive securities excluded from computation of earnings per share (in shares)	47	50
AAP Units | Minimum
Basic and diluted earnings per share
Antidilutive securities excluded from computation of earnings per share (in shares)	1	1
AAP Management Units
Basic and diluted earnings per share
Antidilutive securities excluded from computation of earnings per share (in shares)			1
Class A Shares
Basic Net Income/(Loss) per Class A Share
Basic weighted average Class A shares outstanding (in shares)	194	194	186
Basic net income/(loss) per Class A share (in dollars per share)	$ 0.86	$ 0.31	$ (3.06)
Diluted Net Income/(Loss) per Class A Share
Basic weighted average Class A shares outstanding (in shares)	194	194	186
Dilutive shares resulting from assumed exchange of AAP unit (in shares)	0		60
Diluted weighted average Class A shares outstanding (in shares)	194	194	246
Diluted net income/(loss) per Class A share (in dollars per share)	$ 0.86	$ 0.31	$ (3.07)