Net Income Per Class A Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Basic Net Income per Class A Share
Net income attributable to PAGP from continuing operations	$ 10	$ 30	$ 56	$ 69
Net income attributable to PAGP from discontinued operations	20	9	58	12
Diluted Net Income per Class A Share
Incremental net income attributable to PAGP resulting from assumed exchange of AAP Management Units	0	1	8	0
Net income attributable to PAGP from discontinued operations including incremental net income from assumed exchange of AAP Management Units	$ 20	$ 10	$ 66	$ 12
Class A Shares
Basic Net Income per Class A Share
Basic weighted average Class A shares outstanding (shares)	198,000	197,000	198,000	197,000
Basic Net Income per Class A Share:
Continuing operations (usd per share)	$ 0.05	$ 0.15	$ 0.29	$ 0.35
Discontinued operations (usd per share)	0.10	0.05	0.29	0.06
Basic net income per Class A share (usd per share)	$ 0.15	$ 0.20	$ 0.58	$ 0.41
Diluted Net Income per Class A Share
Dilutive shares resulting from assumed exchange of AAP Management Units (in shares)	0	35,000	35,000
Diluted weighted average Class A shares outstanding (shares)	198,000	232,000	233,000	197,000
Diluted Net Income per Class A Share:
Continuing operations (usd per share)	$ 0.05	$ 0.15	$ 0.29	$ 0.35
Discontinued operations (usd per share)	0.10	0.04	0.28	0.06
Diluted net income per Class A share (usd per share)	$ 0.15	$ 0.19	$ 0.57	$ 0.41
Weighted Average | AAP Units | Held-for-Sale | NGL Business
Basic and Diluted Net Income Per Share
Antidilutive securities excluded from computation of earnings per share (shares)		35,000	35,000