CONSOLIDATED STATEMENTS OF CAPITALIZATION (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Common Stock, Shares Authorized	75,000,000	75,000,000
Common Stock, Shares, Outstanding	41,538,343	41,343,851
COMMON STOCK EQUITY
Common Stock-No Par Value	$ 889,301	$ 882,138
Accumulated Deficit	247,532	193,117
Accumulated Other Comprehensive Loss	(6,049)	(9,790)
Total Common Stock Equity	1,130,784	1,065,465
PREFERRED STOCK
No Par Value, 1,000,000 Shares Authorized, None Outstanding	0	0
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	317,426	352,721
Less Current Maturities	(167,659)	(90,583)
Total Long-Term Capital Lease Obligations	149,767	262,138
LONG-TERM DEBT
Long-term Debt	1,507,070	1,498,442
Total Capitalization	2,787,621	2,826,045
Springerville Unit 1 [Member]
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	192,871	196,843
Springerville Coal Handling Facilities [Member]
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	27,878	48,038
Springerville Common Facilities [Member]
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	96,677	107,840
Parent [Member] | Line of Credit [Member]
LONG-TERM DEBT
Long-term Debt	54,000	45,000
TUCSON ELECTRIC POWER COMPANY
Common Stock, Shares Authorized	75,000,000	75,000,000
Common Stock, Shares, Outstanding	32,139,434	32,139,434
COMMON STOCK EQUITY
Common Stock-No Par Value	888,971	888,971
Capital Stock Expense	(6,357)	(6,357)
Accumulated Deficit	49,185	(12,157)
Accumulated Other Comprehensive Loss	(5,876)	(9,530)
Total Common Stock Equity	925,923	860,927
PREFERRED STOCK
No Par Value, 1,000,000 Shares Authorized, None Outstanding	0	0
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	317,426	352,721
Less Current Maturities	(167,659)	(90,583)
Total Long-Term Capital Lease Obligations	149,767	262,138
LONG-TERM DEBT
Long-term Debt	1,223,070	1,223,442
Total Capitalization	2,298,760	2,346,507
TUCSON ELECTRIC POWER COMPANY | Springerville Unit 1 [Member]
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	192,871	196,843
TUCSON ELECTRIC POWER COMPANY | Springerville Coal Handling Facilities [Member]
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	27,878	48,038
TUCSON ELECTRIC POWER COMPANY | Springerville Common Facilities [Member]
CAPITAL LEASE OBLIGATIONS
Capital Lease Obligations	96,677	107,840
UNS ELECTRIC, INC.
LONG-TERM DEBT
Long-term Debt	130
Unsecured Fixed Rate Bonds [Member] | TUCSON ELECTRIC POWER COMPANY
LONG-TERM DEBT
Long-term Debt	1,008,268	1,008,142
Variable Rate Tax-Exempt Bonds [Member] | TUCSON ELECTRIC POWER COMPANY
LONG-TERM DEBT
Long-term Debt	214,802	215,300
Unsecured Debt [Member] | TUCSON ELECTRIC POWER COMPANY
LONG-TERM DEBT
Long-term Debt	1,008,268	1,008,142
Unsecured Debt [Member] | UNS Gas and UNS Electric [Member]
LONG-TERM DEBT
Long-term Debt	200,000	200,000
Uns Electric Term Loan [Member] | UNS ELECTRIC, INC.
LONG-TERM DEBT
Long-term Debt	$ 30,000	$ 30,000
Minimum [Member] | Unsecured Debt [Member] | TUCSON ELECTRIC POWER COMPANY
LONG-TERM DEBT
Fixed interest rate of Long-Term Debt	3.85%
Minimum [Member] | Unsecured Debt [Member] | UNS Gas and UNS Electric [Member]
LONG-TERM DEBT
Fixed interest rate of Long-Term Debt	5.39%
Maximum [Member] | Unsecured Debt [Member] | TUCSON ELECTRIC POWER COMPANY
LONG-TERM DEBT
Fixed interest rate of Long-Term Debt	5.75%
Maximum [Member] | Unsecured Debt [Member] | UNS Gas and UNS Electric [Member]
LONG-TERM DEBT
Fixed interest rate of Long-Term Debt	7.10%