CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
OPERATING REVENUES:
OPERATING REVENUES	$ 1,026,488		$ 1,017,796		$ 2,378,606		$ 2,333,710
Operating Expenses
Fuel for power generation	171,316		216,779		400,936		519,920
Purchased power	205,686		223,348		486,894		518,672
Gas purchased for resale	5,382		10,137		46,491		87,753
Deferred energy	(29,036)		(33,620)		(30,285)		(43,678)
Energy efficiency program costs	32,584		23,047		76,609		23,047
Other operating expenses	100,108		104,598		307,080		308,119
Maintenance	19,014		11,369		76,190		73,317
Depreciation and amortization	94,512		93,737		281,690		266,445
Taxes other than income	15,682		15,205		44,457		46,134
Total Operating Expenses	615,248		664,600		1,690,062		1,799,729
OPERATING INCOME	411,240		353,196		688,544		533,981
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(73,667)		(80,496)		(226,162)		(238,718)
Interest income (expense) on regulatory items	(2,024)		(1,282)		(6,203)		(3,549)
AFUDC - equity	2,415		1,690		6,666		12,854
Other income	8,827		1,611		19,312		6,351
Other expense	(4,209)		(9,857)		(11,909)		(23,600)
Total Other Income (Expense)	(68,658)		(88,334)		(218,296)		(246,662)
Income Before Income Tax Expense	342,582		264,862		470,248		287,319
Income Tax Expense (Benefit)	119,412		91,400		165,466		98,639
NET INCOME	223,170		173,462		304,782		188,680
Other comprehensive income (loss):
Change in compensation retirement benefits liability and amortization	155		544		464		2,417
Change in market value of risk management assets and liabilities	(193)		0		(668)		0
OTHER COMPREHENSIVE INCOME(LOSS)	(38)		544		(204)		2,417
COMPREHENSIVE INCOME	223,132		174,006		304,578		191,097
Amount per share basic and diluted
Net income per share - basic	$ 0.95		$ 0.74		$ 1.29		$ 0.80
Net income per share - diluted	$ 0.94		$ 0.73		$ 1.28		$ 0.80
Weighted Average Shares of Common Stock Outstanding - basic	235,961,402		235,990,373		235,986,874		235,796,321
Weighted Average Shares of Common Stock Outstanding - diluted	238,121,732	[1]	237,901,330	[1]	237,850,530	[1]	237,320,796	[1]
Dividends Declared Per Share of Common Stock	$ 0.17		$ 0.12		$ 0.47		$ 0.36
Nevada Power Company [Member]
OPERATING REVENUES:
OPERATING REVENUES	802,334		798,914		1,751,165		1,662,880
Operating Expenses
Fuel for power generation	123,992		162,976		285,799		378,790
Purchased power	171,687		181,733		388,494		399,707
Deferred energy	(22,685)		(10,354)		(15,461)		(1,274)
Energy efficiency program costs	28,492		20,451		65,466		20,451
Other operating expenses	65,372		68,004		200,484		195,040
Maintenance	12,533		3,460		52,594		45,122
Depreciation and amortization	66,975		67,212		201,096		186,798
Taxes other than income	9,743		9,105		26,793		28,209
Total Operating Expenses	456,109		502,587		1,205,265		1,252,843
OPERATING INCOME	346,225		296,327		545,900		410,037
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(51,784)		(55,267)		(158,791)		(163,036)
Interest income (expense) on regulatory items	(1,623)		(82)		(5,488)		679
AFUDC - equity	1,833		1,026		4,823		10,979
Other income	7,096		594		14,197		2,708
Other expense	(2,823)		(7,324)		(7,162)		(15,235)
Total Other Income (Expense)	(47,301)		(61,053)		(152,421)		(163,905)
Income Before Income Tax Expense	298,924		235,274		393,479		246,132
Income Tax Expense (Benefit)	103,754		80,666		137,328		84,481
NET INCOME	195,170		154,608		256,151		161,651
Other comprehensive income (loss):
Change in compensation retirement benefits liability and amortization	65		75		192		1,028
COMPREHENSIVE INCOME	195,235		154,683		256,343		162,679
Sierra Pacific Power Company [Member]
OPERATING REVENUES:
Electric	212,073		202,263		549,886		545,462
Gas	12,077		16,615		77,543		125,357
OPERATING REVENUES	224,150		218,878		627,429		670,819
Operating Expenses
Fuel for power generation	47,324		53,803		115,137		141,130
Purchased power	33,999		41,615		98,400		118,965
Gas purchased for resale	5,382		10,137		46,491		87,753
Deferral of energy - electric-net	(5,498)		(22,095)		(13,854)		(45,924)
Deferral of energy - gas-net	(853)		(1,171)		(970)		3,520
Energy efficiency program costs	4,092		2,596		11,143		2,596
Other operating expenses	34,128		35,933		104,214		110,836
Maintenance	6,481		7,909		23,596		28,195
Depreciation and amortization	27,537		26,525		80,594		79,647
Taxes other than income	5,894		6,052		17,382		17,675
Total Operating Expenses	158,486		161,304		482,133		544,393
OPERATING INCOME	65,664		57,574		145,296		126,426
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(15,298)		(16,861)		(47,650)		(50,581)
Interest income (expense) on regulatory items	(401)		(1,200)		(715)		(4,228)
AFUDC - equity	582		664		1,843		1,875
Other income	1,399		810		4,181		2,676
Other expense	(998)		(2,255)		(3,609)		(7,403)
Total Other Income (Expense)	(14,716)		(18,842)		(45,950)		(57,661)
Income Before Income Tax Expense	50,948		38,732		99,346		68,765
Income Tax Expense (Benefit)	16,521		13,396		33,596		23,341
NET INCOME	34,427		25,336		65,750		45,424
Other comprehensive income (loss):
Change in compensation retirement benefits liability and amortization	42		279		127		2,230
COMPREHENSIVE INCOME	$ 34,469		$ 25,615		$ 65,877		$ 47,654

[1] The denominator does not include stock equivalents for options issued under the non-qualified stock option plan due to conversion prices higher than market prices for all periods. If the conditions for conversion were met under this plan, 327,503 and 329,382 shares would be included for the three and nine months ended September 30, 2012, respectively, and 409,080 would be included for both the three and nine months ended September 30, 2011.