SUPPLEMENTAL CASH FLOW INFORMATION (Reconciliation of Net Income to Net Cash Flows from Operating Activities) (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended								12 Months Ended
	Jun. 30, 2013	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Cash Flow Information [Line Items]
Net Income		$ 13,525	$ 67,990	$ 34,618	$ 11,345	$ 7,506	$ 50,664	$ 26,273	$ 6,476	$ 127,478	$ 90,919	$ 109,975
Adjustments to Reconcile Net Income To Net Cash Flows from Operating Activities
Depreciation Expense										149,615	141,303	133,832
Amortization Expense										27,557	35,784	30,983
Depreciation and Amortization Recorded to Fuel and Operations and Maintenance Expense										7,288	6,622	6,140
Amortization of Deferred Debt-Related Costs Included in Interest Expense										3,050	3,000	3,985
Provision for Retail Customer Bad Debts										2,263	2,767	2,072
Use of RECs for Compliance										17,706	5,935	5,695
Deferred Income Taxes										83,501	60,264	75,515
Investment Tax Credit Basis Adjustment	(11,039)										0	0
Pension and Postretirement Expense										22,783	21,856	21,202
Pension and Postretirement Funding										(29,161)	(29,058)	(28,775)
Share-Based Compensation Expense										3,399	2,573	2,599
Allowance for Equity Funds Used During Construction										(6,190)	(3,464)	(4,496)
Increase (Decrease) to Reflect PPFAC/PGA Recovery Treatment										(16,313)	32,246	(4,932)
PPFAC Reduction - TEP Rate Order										3,000	0	0
Competition Transition Charge Revenue Refunded										0	0	(35,958)
Partial Write-off of Tucson to Nogales Transmission Line										0	4,668	0
Liquidated Damages for Springerville Unit 3 Outage										0	2,050	0
Gain on Settlement of El Paso Electric Dispute										0	0	(7,391)
Changes in Assets and Liabilities which Provided (Used) Cash Exclusive of Changes Shown Separately
Accounts Receivable										(6,338)	3,369	2,743
Materials and Fuel Inventory										16,197	(39,429)	(20,864)
Accounts Payable										3,223	595	8,792
Income Taxes										(15,868)	(11,557)	(2,739)
Interest Accrued										4,875	6,922	14,344
Taxes Other Than Income Taxes										1,941	(58)	2,857
Increase (Decrease) in Regulatory Liabilities										11,124	(684)	2,644
Other										20,421	11,486	19,097
Net Cash Flows—Operating Activities										420,512	348,109	337,320
TUCSON ELECTRIC POWER COMPANY
Supplemental Cash Flow Information [Line Items]
Net Income		4,910	64,167	30,787	1,478	452	44,569	21,910	(1,461)	101,342	65,470	85,334
Adjustments to Reconcile Net Income To Net Cash Flows from Operating Activities
Depreciation Expense										118,076	110,931	104,894
Amortization Expense										31,294	39,493	34,650
Depreciation and Amortization Recorded to Fuel and Operations and Maintenance Expense										6,219	5,384	4,509
Amortization of Deferred Debt-Related Costs Included in Interest Expense										2,452	2,227	2,378
Provision for Retail Customer Bad Debts										1,678	1,871	1,447
Use of RECs for Compliance										15,990	5,071	5,190
Deferred Income Taxes										69,950	45,232	59,309
Investment Tax Credit Basis Adjustment										(10,751)	0	0
Pension and Postretirement Expense										19,878	19,289	18,816
Pension and Postretirement Funding										(27,636)	(25,899)	(25,878)
Share-Based Compensation Expense										2,709	2,029	2,027
Allowance for Equity Funds Used During Construction										(4,526)	(2,840)	(3,842)
Increase (Decrease) to Reflect PPFAC/PGA Recovery Treatment										(12,458)	31,113	(6,165)
PPFAC Reduction - TEP Rate Order	3,000									3,000	0	0
Competition Transition Charge Revenue Refunded										0	0	(35,958)
Partial Write-off of Tucson to Nogales Transmission Line										0	4,484	0
Liquidated Damages for Springerville Unit 3 Outage										0	2,050	0
Gain on Settlement of El Paso Electric Dispute										0	0	(7,391)
Changes in Assets and Liabilities which Provided (Used) Cash Exclusive of Changes Shown Separately
Accounts Receivable										(6,041)	(871)	4,809
Materials and Fuel Inventory										16,145	(38,384)	(19,789)
Accounts Payable										334	1,115	14,561
Income Taxes										(10,790)	(11,421)	(5,582)
Interest Accrued										4,859	8,055	14,268
Taxes Other Than Income Taxes										1,425	905	2,282
Increase (Decrease) in Regulatory Liabilities										3,331	(3,040)	303
Other										19,711	5,655	18,122
Net Cash Flows—Operating Activities										$ 346,191	$ 267,919	$ 268,294