REGULATORY ACTIONS, Merger Related and Financing Application (Details) (USD $)	9 Months Ended
	Sep. 30, 2013
Nevada Power Company
Merger Related Activities [Line Items]
Financing Application Date	May 2013
New Authority Requested	$ 705,000,000
Amount Of Requested New Debt Consolidated Authority	1,100,000,000
Amount Of Requested Refinance Consolidated Authority	1,500,000,000
Amount Of Existing Revolver	1,300,000,000
Additional Authority Requested If Extended	255,000,000
Sierra Pacific Power Company
Merger Related Activities [Line Items]
Financing Application Date	May 2013
New Authority Requested	705,000,000
Amount Of Requested New Debt Consolidated Authority	1,100,000,000
Amount Of Requested Refinance Consolidated Authority	1,500,000,000
Amount Of Existing Revolver	$ 600,000,000
MidAmerican Merger | Nevada Power Company
Merger Related Activities [Line Items]
Filing Date of PUCN filing	July 2013
Filing Date of FERC filing	July 12, 2013
Expected Authorization Date FERC	December 19, 2013
Expected Authorization Date PUCN	January 2014
Expected Hearing Date	Nov. 01, 2013
Days To Respond	180 days
AdditionalDaysToRespond	180 days
MidAmerican Merger | Sierra Pacific Power Company
Merger Related Activities [Line Items]
Filing Date of PUCN filing	July 2013
Filing Date of FERC filing	July 12, 2013
Expected Authorization Date FERC	December 19, 2013
Expected Authorization Date PUCN	January 2014
Expected Hearing Date	Nov. 01, 2013
Days To Respond	180 days
AdditionalDaysToRespond	180 days
One Company Merger | Nevada Power Company
Merger Related Activities [Line Items]
Filing Date of PUCN filing	May 2013
Filing Date of FERC filing	May 2013
Expected Hearing Date	Feb. 01, 2014
One Company Merger | Sierra Pacific Power Company
Merger Related Activities [Line Items]
Filing Date of PUCN filing	May 2013
Filing Date of FERC filing	May 2013
Expected Hearing Date	Feb. 01, 2014