LONG-TERM DEBT: Long-term debt narrative Level 4 (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Jan. 31, 2010
6.025% Series due 2018
Debt Instrument [Line Items]
Repayments of Debt	$ 120.0
Gains (Losses) on Extinguishment of Debt	(17.9)
Idaho Power Company
Debt Instrument [Line Items]
Principal amount of debt securities and first mortgage bonds authorized	$ 500.0
Extension Period of State Regulatory Authorization to Issue Debt	2 years
Debt instrument interest rate limit	7.00%
Debt Instrument, Unused Borrowing Capacity, Amount	$ 250.0
Indenture, Unused Borrowing Capacity, Amount	$ 1,500.0
Percent of Operating Revenues Required to be Spent or Appropriated	15.00%
Time Period Expenditures or Appropriations can be Made Up	5 years
Bonds issuable maximum amount ending	$ 2,000.0	$ 1,500.0
Earnings test does not apply to refunding bonds that mature in less than this period of time	2 years