NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Certain amounts from prior periods have been reclassified to conform to the current year presentation. Most notably, TEP combined captions on the Consolidated Statements of Income by reclassifying similar line items into a single line item as follows:



	As Filed			Amount Reclassified			As Reclassified			As Filed			Amount Reclassified			As Reclassified
(in thousands)	Year Ended December 31, 2017									Year Ended December 31, 2016
Other Income (Deductions)
Interest Income	$	742		$	(742	)	$	—		$	111		$	(111	)	$	—
Other Income	14,128			(14,128		)	—			5,636			(5,636		)	—
Other Expense	(3,344		)	3,344			—			(3,019		)	3,019			—
Appreciation in Value of Investments	2,791			(2,791		)	—			2,147			(2,147		)	—
Allowance For Equity Funds	—			5,322			5,322			—			4,522			4,522
Other, Net	—			8,995			8,995			—			353			353

Interest Expense
Long-Term Debt	62,018			(62,018		)	—			62,015			(62,015		)	—
Capital Leases	2,554			(2,554		)	—			3,356			(3,356		)	—
Other Interest Expense	718			(718		)	—			531			(531		)	—
Interest Capitalized	(2,078		)	2,078			—			(1,710		)	1,710			—
Allowance For Borrowed Funds	—			(2,078		)	(2,078		)	—			(1,710		)	(1,710		)
Interest Expense	—			65,290			65,290			—			65,902			65,902

Restrictions on cash and cash equivalents

The following table presents the line items and amounts of cash, cash equivalents, and restricted cash reported on the balance sheet and reconciles their sum to the cash flow statement:



	Years Ended December 31,
(in millions)	2018		2017		2016
Cash and Cash Equivalents	$	138	$	38	$	36
Restricted Cash included in:
Investments and Other Property	14		11		7
Current Assets, Other	1		1		—
Total Cash, Cash Equivalents, and Restricted Cash	$	153	$	50	$	43

Allowance for doubtful accounts

The change in the balance of the Allowance for Doubtful Accounts included in Accounts Receivable, Net on the Consolidated Balance Sheets is summarized as follows:



	Years Ended December 31,
(in millions)	2018			2017			2016
Beginning of Period	$	5		$	5		$	27
Additions Charged to Cost and Expense	3			3			4
Write-offs	(3		)	(3		)	(3		)
Provision for Springerville Unit 1, Third-Party Owners	—			—			(23		)
End of Period	$	5		$	5		$	5

AFUDC rates

The average AFUDC rates on regulated construction expenditures are included in the table below:



	2018		2017		2016
Average AFUDC Rates	7.12	%	7.31	%	7.47	%

Summary of average annual depreciation rates for all utility plants

Below are the summarized average annual depreciation rates for all utility plant:



	2018		2017		2016
Average Annual Depreciation Rates	3.13	%	2.97	%	2.85	%

Schedule of renewable energy credit

The table below does not include PBI activity and summarizes the balance of TEP's RECs which are included in Regulatory and Other Assets—Other on the Consolidated Balance Sheets:



	December 31,
(in millions)	2018			2017
Beginning of Period	$	42		$	24
Purchased	45			43
Used for Compliance	(32		)	(25		)
End of Period	$	55		$	42