CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Common Stock	Treasury stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Nevada Power Company	Nevada Power Company Common Stock	Nevada Power Company Additional Paid-in Capital	Nevada Power Company Retained Earnings	Nevada Power Company Accumulated Other Comprehensive Income (Loss)	Sierra Pacific Power Company	Sierra Pacific Power Company Common Stock	Sierra Pacific Power Company Additional Paid-in Capital	Sierra Pacific Power Company Retained Earnings	Sierra Pacific Power Company Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2011	$ 3,406,079	$ 236,000	$ 0	$ 2,713,736	$ 464,277	$ (7,934)	$ 2,848,977	$ 1	$ 2,308,219	$ 544,874	$ (4,117)	$ 974,542	$ 4	$ 1,111,262	$ (135,340)	$ (1,384)
Balance (in shares) at Dec. 31, 2011		235,999,750	0					1,000					1,000
Net Income	304,782				304,782		256,151			256,151		65,750			65,750
Change in compensation retirement benefits liability and amortization	464					464	192				192	127				127
Change in market value of risk management assets and liabilities	(668)					(668)
Unrealized net gain/(loss) on investment	0
Common stock repurchased	(4,509)		(4,509)
Common stock repurchased (shares)			(252,000)
Dividends Declared	(110,920)				(110,920)		(119,000)			(119,000)		(20,000)			(20,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2012	3,595,228	236,000	(4,509)	2,713,736	658,139	(8,138)	2,986,320	1	2,308,219	682,025	(3,925)	1,020,419	4	1,111,262	(89,590)	(1,257)
Balance (in shares) at Sep. 30, 2012		235,999,750	(252,000)					1,000					1,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2012
Net Income	223,170						195,170					34,427
Change in compensation retirement benefits liability and amortization	155						65					42
Change in market value of risk management assets and liabilities	(193)
Unrealized net gain/(loss) on investment	0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2012	3,595,228	236,000		2,713,736			2,986,320	1	2,308,219			1,020,419	4	1,111,262
Balance (in shares) at Sep. 30, 2012		235,999,750						1,000					1,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2012	3,557,371	236,000	(16,804)	2,712,943	635,303	(10,071)	2,922,318	1	2,308,211	618,612	(4,506)	1,038,736	4	1,111,266	(70,986)	(1,548)
Balance (in shares) at Dec. 31, 2012	235,079,156	235,999,750	(920,594)				1,000	1,000				1,000	1,000
Net Income	271,942				271,942		228,552			228,552		61,931			61,931
Employee Benefits	18,603		15,235	3,368
Dividend Reinvestment and Employee Benefits (in shares)			827,097
Change in compensation retirement benefits liability and amortization	738					738	290				290	176				176
Change in market value of risk management assets and liabilities	485					485
Unrealized net gain/(loss) on investment	33					33
Common stock repurchased	(6,329)		(6,329)
Common stock repurchased (shares)			(325,178)
Dividends Declared	(134,250)				(134,250)		(105,000)			(105,000)		(40,000)			(40,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2013	3,708,593	236,000	(7,898)	2,716,311	772,995	(8,815)	3,046,160	1	2,308,211	742,164	(4,216)	1,060,843	4	1,111,266	(49,055)	(1,372)
Balance (in shares) at Sep. 30, 2013	235,581,074	235,999,750	(418,675)				1,000	1,000				1,000	1,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Jun. 30, 2013
Net Income	187,234						164,442					29,251
Change in compensation retirement benefits liability and amortization	246						96					59
Change in market value of risk management assets and liabilities	(11)
Unrealized net gain/(loss) on investment	98
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Sep. 30, 2013	$ 3,708,593	$ 236,000					$ 3,046,160	$ 1	$ 2,308,211			$ 1,060,843	$ 4	$ 1,111,266
Balance (in shares) at Sep. 30, 2013	235,581,074	235,999,750					1,000	1,000				1,000	1,000