CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 279	$ 228	$ 538	$ 593
Other comprehensive loss	(45)	(311)	0	(518)
Comprehensive income/(loss)	234	(83)	538	75
Comprehensive (income)/loss attributable to noncontrolling interests	(210)	113	(436)	14
Comprehensive income attributable to PAGP	$ 24	$ 30	$ 102	$ 89