Risk Management and Hedging Activities - PacifiCorp - Not Designated as Hedging Contracts (Details) - Not Designated as Hedging Instrument [Member] - Commodity Contract [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Beginning balance	$ 148	$ 250	$ 223
Changes In Fair Value Derivatives Recognized In Regulatory Assets Or Liabilities, Net	53	(30)	128
Net Gains (Losses) Reclassified To Operating Revenue	10	(5)	1
Ending balance	119	148	250
PacifiCorp [Member]
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Beginning balance	73	133	85
Changes In Fair Value Derivatives Recognized In Regulatory Assets Or Liabilities, Net	47	(27)	82
Net Gains (Losses) Reclassified To Operating Revenue	9	10	40
Net Gains (Losses) Reclassified To Cost Of Domestic Regulated Electric	(28)	(43)	(74)
Ending balance	$ 101	$ 73	$ 133