INCOME TAXES: Income Taxes Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Income Tax Disclosures
Unrecognized Tax Benefits	$ 0.0	$ 0.0	$ 0.0
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Percent	0.21	0.21
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			35.00%
Change in net deferred tax liabilities			$ 672.0
Idaho Power Company
Income Tax Disclosures
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Percent	0.21	0.21
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			35.00%
Change in net deferred tax liabilities			$ 672.0
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	7.40%	7.40%	6.925%
IDACORP | General Business Tax Credit Carryforward
Income Tax Disclosures
Additional ADITC amortization available for use	$ 36.7
IDACORP | Investment Tax Credit Carryforward
Income Tax Disclosures
Additional ADITC amortization available for use	$ 39.4