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
	Mar. 31, 2018	Mar. 31, 2017
Regulatory Assets (Liabilities), Net, Unrealized Loss (Gain), Net, on Derivative Instruments [Line Items]
Beginning balance	$ 101	$ 73
Changes in fair value recognized in net regulatory assets	28	24
Net (losses) gains reclassified to operating revenue	7	12
Net Gains (Losses) Reclassified To Cost Of Domestic Regulated Electric	(14)	(6)
Ending balance	$ 122	$ 103