COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Commitments

As of December 31, 2017, TEP had the following firm, non-cancellable, minimum purchase obligations and operating leases:

(in millions)	2018		2019		2020		2021		2022		Thereafter		Total
Fuel, Including Transportation	$	82	$	83	$	73	$	43	$	24	$	244	$	549
Purchased Power	29		—		—		—		—		—		29
Transmission	19		19		8		4		1		8		59
Renewable Power Purchase Agreements	64		64		63		63		63		668		985
RES Performance-Based Incentives	8		8		7		7		7		46		83
Operating Leases (1)	1		1		1		1		1		3		8
Land Easements and Rights-of-Way	1		1		1		2		2		82		89
Total Purchase Commitments	$	204	$	176	$	153	$	120	$	98	$	1,051	$	1,802

⁽¹⁾  Primarily represents leases for land, rail cars, and office facilities with varying terms, provisions, and expiration dates through 2036. TEP's operating lease expense totaled $1 million in 2017, $2 million in 2016, and $3 million in 2015.