Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2014

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets

The components of regulatory assets shown on the balance sheets of SPS at Dec. 31, 2014 and 2013 are:

(Thousands of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2014				Dec. 31, 2013
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Pension and retiree medical obligations (a)	7	Various	$	17,256	$	240,980	$	17,382	$	200,158
Recoverable deferred taxes on AFUDC recorded in plant	1	Plant lives	—		36,878		—		31,362
Net AROs (b)	11	Plant lives	—		21,689		—		21,382
Conservation programs (c)	1	One to six years	3,451		5,020		1,951		7,753
Renewable resources and environmental initiatives	11	One to four years	6,726		5,124		3,428		17,671
Losses on reacquired debt	4	Term of related debt	1,104		2,594		1,225		3,697
Deferred income tax adjustment	1, 6	Typically plant lives	—		302		—		3,375
Recoverable electric energy costs	1	Less than one year	513		—		491		—
Texas Surcharge	10	Less than one year	15,388		—		—		—
Other		Various	7,568		10,718		3,118		5,017
Total regulatory assets			$	52,006	$	323,305	$	27,595	$	290,415

^(a)  Includes the non-qualified pension plan.

^(b)  Includes amounts recorded for future recovery of AROs.

^(c)  Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.

Regulatory Liabilities

The components of regulatory liabilities shown on the balance sheets of SPS at Dec. 31, 2014 and 2013 are:

(Thousands of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2014				Dec. 31, 2013
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Plant removal costs	11	Plant lives	$	—	$	68,106	$	—	$	53,006
Deferred electric energy costs	1	Less than one year	53,971		—		55,395		—
Contract valuation adjustments (a)	1, 9	Term of related contract	20,211		2,521		14,243		6,849
Gain from asset sales	10	Various	2,577		4,468		11,172		4,201
Conservation programs (b)	1	Less than one year	1,425		—		1,465		—
Other		Various	9,539		40,093		1,484		17,448
Total regulatory liabilities			$	87,723	$	115,188	$	83,759	$	81,504

^(a)  Includes the fair value of certain long-term PPAs used to meet energy capacity requirements.

^(b)  Includes costs for conservation programs as well as incentives allowed in certain jurisdictions.