SUPPLEMENTAL CASH FLOW INFORMATION (Reconciliation of Net Income to Net Cash Flows from Operating Activities) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Supplemental Cash Flow Information [Line Items]
Net Income	$ 42,354	$ 34,618	$ 57,829	$ 45,963
Adjustments to Reconcile Net Income To Net Cash Flows from Operating Activities
Depreciation Expense	39,563	36,671	78,644	72,970
Amortization Expense	6,455	8,119	12,631	16,408
Depreciation and Amortization Recorded to Fuel and Operations and Maintenance Expense			3,977	3,516
Amortization of Deferred Debt-Related Costs Included in Interest Expense			1,584	1,515
Provision for Retail Customer Bad Debts			1,194	936
Use of RECs for Compliance			11,313	8,106
Deferred Income Taxes			36,320	36,644
Investment Tax Credit Basis Adjustment	0	(11,000)	0	(11,039)
Pension and Postretirement Expense			7,884	11,391
Pension and Postretirement Funding			(5,974)	(8,924)
Share-Based Compensation Expense			1,859	1,390
Allowance for Equity Funds Used During Construction			(4,038)	(2,463)
Revenue Recognized Under Lost Fixed Cost Recovery Mechanism			(7,654)
Increase (Decrease) to Reflect PPFAC/PGA Recovery Treatment	(12,517)	2,074	(21,437)	(3,294)
PPFAC Reduction - 2013 TEP Rate Order			0	3,000
Changes in Assets and Liabilities which Provided (Used) Cash Exclusive of Changes Shown Separately
Accounts Receivable			(22,766)	(20,706)
Materials and Fuel Inventory			(4,413)	8,777
Accounts Payable			(5,875)	(9,576)
Income Taxes			(88)	(15,980)
Interest Accrued			1,305	(6,885)
Taxes Other Than Income Taxes			3,721	490
Other			(8,259)	15,413
Net Cash Flows—Operating Activities			137,757	147,652
TUCSON ELECTRIC POWER COMPANY
Supplemental Cash Flow Information [Line Items]
Net Income	38,725	30,787	47,897	32,266
Adjustments to Reconcile Net Income To Net Cash Flows from Operating Activities
Depreciation Expense	31,080	28,861	61,891	57,418
Amortization Expense	7,377	9,052	14,476	18,275
Depreciation and Amortization Recorded to Fuel and Operations and Maintenance Expense			3,406	2,987
Amortization of Deferred Debt-Related Costs Included in Interest Expense			1,285	1,216
Provision for Retail Customer Bad Debts			833	711
Use of RECs for Compliance			9,884	7,414
Deferred Income Taxes			29,641	24,883
Investment Tax Credit Basis Adjustment	0	(11,000)	0	(10,751)
Pension and Postretirement Expense			6,824	9,939
Pension and Postretirement Funding			(5,522)	(8,493)
Share-Based Compensation Expense			1,496	1,108
Allowance for Equity Funds Used During Construction			(3,524)	(1,763)
Revenue Recognized Under Lost Fixed Cost Recovery Mechanism			(6,121)	0
Increase (Decrease) to Reflect PPFAC/PGA Recovery Treatment	(13,061)	5,274	(14,791)	2,914
PPFAC Reduction - 2013 TEP Rate Order			0	3,000
Changes in Assets and Liabilities which Provided (Used) Cash Exclusive of Changes Shown Separately
Accounts Receivable			(35,498)	(30,452)
Materials and Fuel Inventory			(3,936)	8,923
Accounts Payable			6,019	(11)
Income Taxes			(6)	(10,798)
Interest Accrued			1,320	(6,886)
Taxes Other Than Income Taxes			5,247	2,295
Other			(7,779)	11,347
Net Cash Flows—Operating Activities			$ 113,042	$ 115,542