CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
OPERATING REVENUES:
OPERATING REVENUES	$ 584,222		$ 611,420
Operating Expenses
Fuel for power generation	147,248		117,035
Purchased power	121,310		117,116
Gas purchased for resale	37,620		31,617
Deferred energy	(79,065)		(11,739)
Energy efficiency program costs	9,845		19,425
Other operating expenses	104,672		103,601
Maintenance	24,906		32,526
Depreciation and amortization	96,002		90,862
Taxes other than income	16,476		14,509
Total Operating Expenses	479,014		514,952
OPERATING INCOME	105,208		96,468
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(73,337)		(77,931)
Interest income (expense) on regulatory items	(827)		(2,202)
AFUDC - equity	2,889		1,932
Other income	3,820		4,194
Other expense	(4,251)		(3,060)
Total Other Income (Expense)	(71,706)		(77,067)
Income Before Income Tax Expense	33,502		19,401
Income Tax Expense (Benefit)	12,027		7,228
NET INCOME	21,475		12,173
Other comprehensive income (loss):
Change in compensation retirement benefits liability and amortization	246		155
Change in market value of risk management assets and liabilities	(199)		246
OTHER COMPREHENSIVE INCOME(LOSS)	445		(91)
COMPREHENSIVE INCOME	21,920		12,082
Amount per share basic and diluted
Earnings Per Share, Basic and Diluted	$ 0.09		$ 0.05
Net income per share - basic	$ 0.09		$ 0.05
Net income per share - diluted	$ 0.09		$ 0.05
Weighted Average Shares of Common Stock Outstanding - basic	235,193,702		235,999,750
Weighted Average Shares of Common Stock Outstanding - diluted	237,005,888	[1]	237,526,863	[1]
Dividends Declared Per Share of Common Stock	$ 0.19		$ 0.13
Nevada Power Company [Member]
OPERATING REVENUES:
OPERATING REVENUES	371,863		395,688
Operating Expenses
Fuel for power generation	105,531		80,549
Purchased power	81,408		81,531
Deferred energy	(45,355)		2,171
Energy efficiency program costs	7,967		15,774
Other operating expenses	67,392		66,462
Maintenance	18,075		23,073
Depreciation and amortization	68,661		64,990
Taxes other than income	9,959		8,454
Total Operating Expenses	313,638		343,004
OPERATING INCOME	58,225		52,684
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(51,259)		(54,405)
Interest income (expense) on regulatory items	(802)		(2,016)
AFUDC - equity	2,366		1,413
Other income	2,404		1,709
Other expense	(2,401)		(1,346)
Total Other Income (Expense)	(49,692)		(54,645)
Income Before Income Tax Expense	8,533		(1,961)
Income Tax Expense (Benefit)	3,088		(645)
NET INCOME	5,445		(1,316)
Other comprehensive income (loss):
Change in compensation retirement benefits liability and amortization	97		63
COMPREHENSIVE INCOME	5,542		(1,253)
Sierra Pacific Power Company [Member]
OPERATING REVENUES:
Electric	172,627		169,806
Gas	39,729		45,922
OPERATING REVENUES	212,356		215,728
Operating Expenses
Fuel for power generation	41,717		36,486
Purchased power	39,902		35,585
Gas purchased for resale	37,620		31,617
Deferral of energy - electric-net	(19,335)		(12,670)
Deferral of energy - gas-net	(14,375)		(1,240)
Energy efficiency program costs	1,878		3,651
Other operating expenses	35,805		36,432
Maintenance	6,831		9,453
Depreciation and amortization	27,341		25,872
Taxes other than income	6,295		5,863
Total Operating Expenses	163,679		171,049
OPERATING INCOME	48,677		44,679
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(15,525)		(16,973)
Interest income (expense) on regulatory items	(25)		(186)
AFUDC - equity	523		519
Other income	1,140		2,183
Other expense	(1,248)		(1,335)
Total Other Income (Expense)	(15,135)		(15,792)
Income Before Income Tax Expense	33,542		28,887
Income Tax Expense (Benefit)	11,638		10,243
NET INCOME	21,904		18,644
Other comprehensive income (loss):
Change in compensation retirement benefits liability and amortization	59		42
COMPREHENSIVE INCOME	$ 21,963		$ 18,686

[1] The denominator does not include stock equivalents for options issued under the non-qualified stock option plan due to conversion prices being higher than market prices for the prior period. If the conditions for conversion were met under this plan, 0 and 333,140 shares would be included for the three months ended March 31, 2013 and 2012, respectively.