Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (71)	$ (31)	$ (147)	$ (46)
Other comprehensive income (loss):
Change in foreign currency translation, net of zero tax impact for all periods presented	(3)	3	10	(20)
Cash flow hedge activity:
Change in unrealized gain (loss) on cash flow hedges, net of tax impact of $(1), $(2), $(7) and $(1), respectively	(13)	12	(59)	21
Reclassifications to net loss, net of tax impact of less than $1 for all periods presented	1	1	2	2
Total change in cash flow hedge activity	(12)	13	(57)	23
Other comprehensive income (loss) related to equity method investee net of tax impact of less than $(1), ($1), $(2) and ($1), respectively	(1)	5	(6)	9
Total other comprehensive gain (loss), net of tax	(16)	21	(53)	12
Comprehensive loss	(87)	(10)	(200)	(34)
Comprehensive loss attributable to noncontrolling interests, net of tax impact of less than $1 for all periods presented	(23)	(15)	(64)	(200)
Comprehensive income (loss) attributable to Pattern Energy	$ (64)	$ 5	$ (136)	$ 166