Risk Management and Hedging Activities - PacifiCorp - Derivative Contract Volumes (Details) - Commodity derivative [Member] gal in Millions, MWh in Millions, Dth in Millions	Jun. 30, 2017 gal Dth MWh	Dec. 31, 2016 gal Dth MWh
Electricity purchases (in megawatt hours) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | MWh	(11)	(5)
Natural gas purchases (in decatherms) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | Dth	(279)	(271)
Fuel purchases (in gallons) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | gal	(5)	(11)
PacifiCorp [Member] | Electricity purchases (in megawatt hours) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | MWh	(1)	(3)
PacifiCorp [Member] | Natural gas purchases (in decatherms) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | Dth	(85)	(84)
PacifiCorp [Member] | Fuel purchases (in gallons) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, nonmonetary notional amount | gal	(5)	(11)