CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
OTHER INCOME (EXPENSE):
AFUDC-debt	$ 1,957	$ 1,976	$ 5,770	$ 5,479
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	(133)	(74)	(398)	(246)
Market value of risk management assets and liabilities	(154)	91	(261)	355
Unrealized net gain/(loss) on investments	(49)	0	(18)	0
Nevada Power Company
OTHER INCOME (EXPENSE):
AFUDC-debt	1,520	1,528	4,763	4,021
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	(52)	(33)	(156)	(103)
Sierra Pacific Power Company
OTHER INCOME (EXPENSE):
AFUDC-debt	437	448	1,007	1,458
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	$ (32)	$ (22)	$ (95)	$ (68)