Operating Segments - Reconciliation of Segment Profit (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reconciliation of segment profit to net income attributable to PAGP
Segment profit	$ 428	$ 487	$ 1,261	$ 1,371
Unallocated general and administrative expenses	(71)	(60)	(212)	(219)
Depreciation and amortization	(33)	(108)	(352)	(320)
Interest expense, net	(116)	(112)	(349)	(329)
Other income/(expense), net	17	(4)	46	(7)
INCOME BEFORE TAX	295	263	604	713
Income tax expense	(16)	(35)	(66)	(120)
NET INCOME	279	228	538	593
Net income attributable to noncontrolling interests	(255)	(196)	(436)	(500)
NET INCOME ATTRIBUTABLE TO PAGP	24	$ 32	102	93
Unallocated
Reconciliation of segment profit to net income attributable to PAGP
Unallocated general and administrative expenses	$ (1)		$ (2)	$ (2)