Risk Management and Hedging Activities - PacifiCorp - Not Designated as Hedging Contracts (Details) - PacifiCorp [Member] - Not Designated as Hedging Instrument [Member] - Commodity derivative [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Regulatory Assets (Liabilities), Net, Unrealized Loss (Gain), Net, on Derivative Instruments [Line Items]
Beginning balance	$ 116	$ 95	$ 101	$ 73
Changes in fair value recognized in net regulatory assets	14	6	48	36
Net (losses) gains reclassified to operating revenue	(36)	(5)	(30)	8
Net Gains (Losses) Reclassified To Cost Of Domestic Regulated Electric	8	1	(17)	(20)
Ending balance	$ 102	$ 97	$ 102	$ 97