Document And Entity Information (USD $)	9 Months Ended
	Sep. 30, 2011	Jun. 30, 2011
Entity Information [Line Items]
Entity Registrant Name	NV Energy, Inc.
Entity Central Index Key	0000741508
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float		$ 3,622,247,595
Entity Common Stock, Shares Outstanding	235,999,749
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	0
Document Period End Date	Sep. 30, 2011
Nevada Power Company [Member]
Entity Information [Line Items]
Entity Registrant Name	NEVADA POWER CO
Entity Central Index Key	0000071180
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float	0
Entity Common Stock, Shares Outstanding	1,000
Sierra Pacific Power Company [Member]
Entity Information [Line Items]
Entity Registrant Name	SIERRA PACIFIC POWER CO
Entity Central Index Key	0000090144
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float	$ 0
Entity Common Stock, Shares Outstanding	1,000