Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities:
Net Income	$ 193,754	$ 182,294	$ 173,187
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	137,088	133,776	128,611
Deferred income taxes and investment tax credits	19,163	65,568	33,985
Changes in regulatory assets and liabilities	32,135	(25,581)	(53,468)
Pension and postretirement benefit plan expense	44,627	45,907	45,230
Contributions to pension and postretirement benefit plans	(33,720)	(33,393)	(47,695)
Earnings of unconsolidated equity-method investments	(12,372)	(11,939)	(11,617)
Distributions from unconsolidated equity-method investments	5,261	17,526	18,546
Allowance for equity funds used during construction	(17,931)	(14,858)	(22,433)
Gain on sale of investments and assets	(193)	(11,678)	(202)
Other non-cash adjustments to net income, net	5,085	3,297	6,121
Change in:
Accounts receivable	20,433	(29,557)	(2,741)
Accounts payable and other accrued liabilities	6,359	(517)	10,580
Taxes accrued/receivable	(13,631)	4,747	(604)
Other current assets	(13,124)	(12,165)	(5,255)
Other current liabilities	1,771	1,819	(8,500)
Other assets	(3,655)	(830)	(7,064)
Other liabilities	(6,707)	(8,867)	(7,412)
Net cash provided by operating activities	364,343	305,549	249,269
Investing Activities:
Additions to property, plant and equipment	(274,094)	(235,310)	(239,788)
Proceeds from the sale of utility assets	620	0	0
Proceeds from the sale of emission allowances and RECs	2,931	498	2,739
Investments in affordable housing	0	0	(381)
Distributions from affordable housing investments	1,161	1,746	242
Purchase of available-for-sale securities	(8,000)	(32,661)	(7,000)
Proceeds from sale of available-for-sale securities	0	25,661	0
Other	4,962	3,473	367
Net cash used in investing activities	(272,420)	(236,593)	(243,821)
Financing Activities:
Issuance of long-term debt	0	150,000	150,000
Retirement of long-term debt	(1,064)	(71,064)	(101,064)
Dividends on common stock	(88,489)	(78,832)	(68,928)
Net change in short-term borrowings	(23,450)	(14,950)	15,500
Issuance of common stock	195	255	4,882
Acquisition of treasury stock	(2,737)	(2,124)	(2,062)
Other	2,268	(606)	(5,062)
Net cash used in financing activities	(113,277)	(17,321)	(6,734)
Net (decrease) increase in cash and cash equivalents	(21,354)	51,635	(1,286)
Cash and cash equivalents at beginning of the year	78,162	26,527	27,813
Cash and cash equivalents at end of the year	56,808	78,162	26,527
Cash paid (received) during the period for:
Income taxes	11,364	1,437	1,451
Interest (net of amount capitalized)	77,295	77,968	70,887
Non-cash investing activities:
Additions to property, plant and equipment in accounts payable	28,438	24,246	26,882
Idaho Power Company
Operating Activities:
Net Income	189,387	176,741	168,168
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	136,496	133,135	128,009
Deferred income taxes and investment tax credits	15,454	59,355	48,255
Changes in regulatory assets and liabilities	32,135	(25,581)	(53,467)
Pension and postretirement benefit plan expense	44,579	45,861	45,230
Contributions to pension and postretirement benefit plans	(33,672)	(33,347)	(47,695)
Earnings of unconsolidated equity-method investments	(10,814)	(10,242)	(9,412)
Distributions from unconsolidated equity-method investments	3,586	14,901	17,921
Allowance for equity funds used during construction	(17,931)	(14,858)	(22,433)
Gain on sale of investments and assets	(186)	(11,678)	(202)
Other non-cash adjustments to net income, net	2,087	629	438
Change in:
Accounts receivable	20,072	(31,472)	(3,344)
Accounts payable and other accrued liabilities	6,183	(397)	10,762
Taxes accrued/receivable	(22,911)	6,740	3,301
Other current assets	(13,137)	(12,166)	(5,252)
Other current liabilities	1,776	1,721	(8,506)
Other assets	(3,655)	(831)	(7,064)
Other liabilities	(6,238)	(8,603)	(6,856)
Net cash provided by operating activities	343,211	289,908	257,853
Investing Activities:
Additions to property, plant and equipment	(273,911)	(235,306)	(239,761)
Proceeds from the sale of utility assets	620	0	0
Proceeds from the sale of emission allowances and RECs	2,931	498	2,739
Purchase of available-for-sale securities	(8,000)	(32,661)	(7,000)
Proceeds from sale of available-for-sale securities	0	25,661	0
Other	4,957	3,473	367
Net cash used in investing activities	(273,403)	(238,335)	(243,655)
Financing Activities:
Issuance of long-term debt	0	150,000	150,000
Retirement of long-term debt	(1,064)	(71,064)	(101,064)
Dividends on common stock	(88,584)	(78,926)	(68,740)
Capital contribution from parent	0	0	7,500
Other	0	(2,299)	(3,959)
Net cash used in financing activities	(89,648)	(2,289)	(16,263)
Net (decrease) increase in cash and cash equivalents	(19,840)	49,284	(2,065)
Cash and cash equivalents at beginning of the year	66,535	17,251	19,316
Cash and cash equivalents at end of the year	46,695	66,535	17,251
Cash paid (received) during the period for:
Income taxes	26,116	9,667	(14,558)
Interest (net of amount capitalized)	77,063	77,583	70,447
Non-cash investing activities:
Additions to property, plant and equipment in accounts payable	$ 28,438	$ 24,246	$ 26,882