Commitments and Contingencies - Commitments (Details) - PacifiCorp [Member] - Klamath Hydroelectric System [Member] $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)
ContractualObligationFiscalYearMaturityScheduleTable [Line Items]
Dam removal cost limit	$ 200
OREGON
ContractualObligationFiscalYearMaturityScheduleTable [Line Items]
Dam removal cost limit	184
CALIFORNIA
ContractualObligationFiscalYearMaturityScheduleTable [Line Items]
Dam removal cost limit	16
Additional dam removal costs, California bond measure	$ 250