Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 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	235,999,750
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011
NPC [Member]
Entity Information [Line Items]
Entity Registrant Name	Nevada Power Company
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 Common Stock, Shares Outstanding	1,000
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011
SPPC [Member]
Entity Information [Line Items]
Entity Registrant Name	Sierra Pacific Power Company
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 Common Stock, Shares Outstanding	1,000
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011