Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Apr. 17, 2014
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2014
Document Fiscal Year Focus	2014	2013
Document Fiscal Period Focus	Q1
Trading Symbol	UNS
Entity Registrant Name	UNS Energy Corp
Entity Central Index Key	0000941138
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filer	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding			41,701,718
TUCSON ELECTRIC POWER COMPANY
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Entity Registrant Name	TUCSON ELECTRIC POWER COMPANY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filer	No
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding			32,139,434