DEBT, CREDIT FACILITY, AND CAPITAL LEASE OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

DEBT

Long-term debt matures more than one year from the date of the financial statements. The following table presents the components of Long-Term Debt, Net on the Consolidated Balance Sheets:

			December 31,
(dollars in millions)	Interest Rate	Maturity Date	2016		2015
Notes
2011 Notes	5.15%	2021	$	250	$	250
2012 Notes	3.85%	2023	150		150
2014 Notes	5.00%	2044	150		150
2015 Notes	3.05%	2025	300		300
Tax-Exempt Local Furnishings Bonds
2010 Pima A	5.25%	2040	100		100
2012 Pima A	4.50%	2030	16		16
2013 Pima A	4.00%	2029	91		91
2013 Apache A (1)	1.01%	2032	100		100
Tax-Exempt Pollution Control Bonds
2009 Pima A	4.95%	2020	80		80
2009 Coconino A	5.13%	2032	15		15
2010 Coconino A (2)	1.33%	2032	37		37
2012 Apache A	4.50%	2030	177		177
Total Long-Term Debt (3)			1,466		1,466
Less Unamortized Discount and Debt Issuance Costs			13		14
Total Long-Term Debt, Net			$	1,453	$	1,452

⁽¹⁾  The bonds are variable rate debt for which rates are reset monthly. The interest rate is calculated using a weighted average based on a percentage of an index equal to one-month LIBOR plus a credit spread. The bonds are subject to mandatory tender for purchase in 2018.

⁽²⁾  The bonds are variable rate debt for which rates are reset weekly. The interest rate is calculated using a weighted average and includes LOC fees and remarketing fees. The bonds are backed by an LOC issued pursuant to the 2010 Reimbursement Agreement, which expires in December 2019.

⁽³⁾  As of December 31, 2016, all of TEP's debt is unsecured, with the exception of the 2010 Coconino A variable rate bonds, which are backed by a LOC.

Schedule of Capital Lease Obligations [Table Text Block]

CAPITAL LEASE OBLIGATIONS

The following table details Capital Lease Obligations on the Consolidated Balance Sheets:

	December 31,
(in millions)	2016		2015
Capital Lease Obligations	$	91	$	69
Less Current Obligations Under Capital Leases	52		14
Total Capital Lease Obligations, Non-Current	$	39	$	55

Schedule of Maturities of Long-term Debt [Table Text Block]

DEBT MATURITIES

Long-term debt, including revolving credit facilities classified as long-term, and capital lease obligations mature on the following dates:

(in millions)	Long-Term Debt(1)		Capital Lease Obligations			Total Debt Maturities(2)
2017	$	—	$	52		$	52
2018	100		11			111
2019	37		11			48
2020	80		18			98
2021	250		—			250
Total 2017 - 2021	467		92			559
Thereafter	999		—			999
Less: Imputed Interest	—		(1		)	(1		)
Total	$	1,466	$	91		$	1,557

⁽¹⁾  $37 million of TEP’s variable rate bonds are backed by an LOC issued pursuant to the 2010 Reimbursement Agreement, which expires in December 2019. Although the variable rate bond matures in 2032, the above table reflects a redemption or repurchase of such bond in 2019 as though the LOC terminates without replacement upon expiration of the 2010 Reimbursement Agreement. TEP's 2013 tax-exempt variable rate IDRBs, which have an aggregate principal amount of $100 million and mature in 2032, are subject to mandatory tender for purchase in 2018.

⁽²⁾  Total long-term debt excludes $10 million of related unamortized debt issuance costs and $3 million of unamortized original issue discount.