CONSOLIDATED INCOME STATEMENTS (Unaudited) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
OPERATING REVENUES	$ 1,017,796,000	[1]	$ 1,128,039,000	[2],[3]	$ 2,333,710,000	[1]	$ 2,625,211,000	[2],[3]
OPERATING EXPENSES:
Fuel for power generation	216,779,000		247,233,000		519,920,000		650,514,000
Purchased power	223,348,000		249,854,000		518,672,000		522,538,000
Gas purchased for resale	10,137,000		10,823,000		87,753,000		101,536,000
Deferred energy	(33,620,000)		34,055,000		(43,678,000)		106,554,000
Other operating expenses	127,645,000	[1]	112,741,000		331,166,000	[1]	320,755,000
Maintenance	11,369,000		31,126,000		73,317,000		85,715,000
Depreciation and amortization	93,737,000		83,423,000		266,445,000		249,067,000
Taxes other than income	15,205,000		15,420,000		46,134,000		47,532,000
Total Operating Expenses	664,600,000		784,675,000		1,799,729,000		2,084,211,000
OPERATING INCOME	353,196,000		343,364,000	[3]	533,981,000		541,000,000	[3]
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(80,496,000)		(80,789,000)		(238,718,000)		(241,625,000)
Interest expense on regulatory items	(4,316,000)		(3,685,000)		(12,140,000)		(8,753,000)
AFUDC-equity	1,690,000		7,824,000		12,854,000		20,915,000
Other income	4,645,000		9,246,000		14,942,000		30,524,000
Other expense	(9,857,000)		(4,313,000)		(23,600,000)		(17,038,000)
Total Other Income (Expense)	(88,334,000)		(71,717,000)		(246,662,000)		(215,977,000)
Income Before Income Tax Expense	264,862,000		271,647,000		287,319,000		325,023,000
Income tax expense	91,400,000		94,101,000		98,639,000		112,252,000
NET INCOME	173,462,000		177,546,000	[4]	188,680,000		212,771,000	[4]
Amount per share basic and diluted - (Note 9)
Net income per share - basic	$ 0.74		$ 0.76	[4]	$ 0.80		$ 0.91	[4]
Net income per share - diluted	$ 0.73		$ 0.75	[4]	$ 0.80		$ 0.90	[4]
Weighted Average Shares of Common Stock Outstanding - basic	235,990,373		235,117,058		235,796,321		234,991,208
Weighted Average Shares of Common Stock Outstanding - diluted	237,901,330	[5]	236,477,187	[5]	237,320,796	[5]	236,136,725	[5]
Dividends Declared Per Share of Common Stock	$ 0.12		$ 0.11		$ 0.36		$ 0.33
Nevada Power Company [Member]
OPERATING REVENUES	798,914,000	[1]	870,950,000	[2],[3]	1,662,880,000	[1]	1,836,144,000	[2],[3]
OPERATING EXPENSES:
Fuel for power generation	162,976,000		181,100,000		378,790,000		469,282,000
Purchased power	181,733,000		216,309,000		399,707,000		412,276,000
Deferred energy	(10,354,000)		22,296,000		(1,274,000)		81,719,000
Other operating expenses	88,455,000	[1]	73,762,000		215,491,000		203,773,000
Maintenance	3,460,000		23,707,000		45,122,000		58,945,000
Depreciation and amortization	67,212,000		56,575,000		186,798,000		169,330,000
Taxes other than income	9,105,000		9,038,000		28,209,000		28,857,000
Total Operating Expenses	502,587,000		582,787,000		1,252,843,000		1,424,182,000
OPERATING INCOME	296,327,000		288,163,000	[3]	410,037,000		411,962,000
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(55,267,000)		(54,144,000)		(163,036,000)		(161,496,000)
Interest expense on regulatory items	(2,478,000)		(1,157,000)		(5,911,000)		(1,965,000)
AFUDC-equity	1,026,000		6,795,000		10,979,000		18,555,000
Other income	2,990,000		3,842,000		9,298,000		9,084,000
Other expense	(7,324,000)		(3,034,000)		(15,235,000)		(9,338,000)
Total Other Income (Expense)	(61,053,000)		(47,698,000)		(163,905,000)		(145,160,000)
Income Before Income Tax Expense	235,274,000		240,465,000		246,132,000		266,802,000
Income tax expense	80,666,000		81,537,000		84,481,000		90,416,000
NET INCOME	154,608,000		158,928,000		161,651,000		176,386,000
Sierra Pacific Power Company [Member]
Electric	202,263,000		237,798,000		545,462,000		649,337,000
Gas	16,615,000		19,286,000		125,357,000		139,711,000
OPERATING REVENUES	218,878,000	[1]	257,084,000		670,819,000	[1]	789,048,000
OPERATING EXPENSES:
Fuel for power generation	53,803,000		66,133,000		141,130,000		181,232,000
Purchased power	41,615,000		33,545,000		118,965,000		110,262,000
Gas purchased for resale	10,137,000		10,823,000		87,753,000		101,536,000
Deferral of energy - electric - net	(22,095,000)		9,964,000		(45,924,000)		17,189,000
Deferral of energy - gas - net	(1,171,000)		1,795,000		3,520,000		7,646,000
Other operating expenses	38,529,000	[1]	38,004,000		113,432,000		114,371,000
Maintenance	7,909,000		7,419,000		28,195,000		26,770,000
Depreciation and amortization	26,525,000		26,848,000		79,647,000		79,737,000
Taxes other than income	6,052,000		6,330,000		17,675,000		18,494,000
Total Operating Expenses	161,304,000		200,861,000		544,393,000		657,237,000
OPERATING INCOME	57,574,000		56,223,000		126,426,000		131,811,000
OTHER INCOME (EXPENSE):
Interest expense (net of AFUDC-debt)	(16,861,000)		(16,983,000)		(50,581,000)		(51,141,000)
Interest expense on regulatory items	(1,838,000)		(2,528,000)		(6,229,000)		(6,788,000)
AFUDC-equity	664,000		1,029,000		1,875,000		2,360,000
Other income	1,448,000		2,379,000		4,677,000		14,276,000
Other expense	(2,255,000)		(1,285,000)		(7,403,000)		(7,555,000)
Total Other Income (Expense)	(18,842,000)		(17,388,000)		(57,661,000)		(48,848,000)
Income Before Income Tax Expense	38,732,000		38,835,000		68,765,000		82,963,000
Income tax expense	13,396,000		14,373,000		23,341,000		30,066,000
NET INCOME	$ 25,336,000		$ 24,462,000		$ 45,424,000		$ 52,897,000

[1] Effective July 1, 2011, included in operating revenues were EEPR revenues, for which costs related to the program are included in other operating expense and therefore have no effect on operating income. See Note 3, Regulatory Actions.

[2] As reported in our 2010 Form 10-K, amounts for REPR are presented net. As such, revenues and gross margin for the three months ended September 30, 2010 were reduced by $3.5 million, $2.0 million and $1.5 million for NVE, NPC and SPPC, respectively, from that reported in the Forms 10-Q for the period ended September 30, 2010. Revenues and gross margin for the nine months ended September 30, 2010 were reduced by $8.7 million, $4.6 million and $4.1 million for NVE, NPC and SPPC, respectively, from that reported in the Forms 10-Q for the period ended September 30, 2010.

[3] During the third quarter 2010, NPC terminated a long-term service agreement from one of its generating stations. The estimated termination payment was not considered material to the third quarter but would have been material to the fourth quarter; therefore, as disclosed in our 2010 Form 10-K, third quarter 2010 was revised to reflect the estimated termination payment. As such, operating income for the three and nine months ended September 30, 2010 was reduced by $8.0 million, before tax, for NVE and NPC, from that reported in the Forms 10-Q for the quarterly period ended September 30, 2010. See Note 1, Summary of Significant Accounting Policies.

[4] As discussed in Note 1, Summary of Significant Accounting Policies, net income and earnings per share basic and diluted were reduced from that previously reported by $5.2 million (net of taxes) and $0.02 per share (net of taxes), respectively.

[5] 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 all periods. If the conditions for conversion were met under this plan, 572,825 and 575,846 shares would be included for the three and nine months ended September 30, 2011, and 701,190 and 707,950 would be included for the three and nine months ended September 30, 2010, respectively.