Benefit Plans and Other Postretirement Benefits (Tables)

12 Months Ended

Dec. 31, 2014

Benefit Plans and Other Postretirement Benefits [Abstract]

Projected Benefit Payments for the Pension and Postretirement Benefit Plans

Projected Benefit Payments — The following table lists SPS’ projected benefit payments for the pension and postretirement benefit plans:

(Thousands of Dollars)	Projected Pension Benefit Payments		Gross Projected Postretirement Health Care Benefit Payments		Expected Medicare Part D Subsidies		Net Projected Postretirement Health Care Benefit Payments
2015	$	25,988	$	3,166	$	24	$	3,142
2016	27,029		3,171		31		3,140
2017	27,674		3,119		32		3,087
2018	28,896		3,034		30		3,004
2019	29,377		2,992		29		2,963
2020-2024	156,430		14,498		153		14,345

Pension Plans

Benefit Plans and Other Postretirement Benefits [Abstract]

Target Asset Allocations and Plan Assets Measured at Fair Value

The following tables present, for each of the fair value hierarchy levels, SPS’ pension plan assets that are measured at fair value as of Dec. 31, 2014 and 2013:

	Dec. 31, 2014
(Thousands of Dollars)	Level 1		Level 2			Level 3		Total
Cash equivalents	$	17,181	$	—		$	—	$	17,181
Derivatives	—		748			—		748
Government securities	—		68,058			—		68,058
Corporate bonds	—		46,531			—		46,531
Asset-backed securities	—		494			—		494
Mortgage-backed securities	—		1,451			—		1,451
Common stock	13,439		—			—		13,439
Private equity investments	—		—			18,331		18,331
Commingled funds	—		233,232			—		233,232
Real estate	—		—			6,689		6,689
Securities lending collateral obligation and other	—		(3,885		)	—		(3,885		)
Total	$	30,620	$	346,629		$	25,020	$	402,269

	Dec. 31, 2013
(Thousands of Dollars)	Level 1		Level 2		Level 3		Total
Cash equivalents	$	17,354	$	—	$	—	$	17,354
Derivatives	—		4,200		—		4,200
Government securities	—		26,649		—		26,649
Corporate bonds	—		79,635		—		79,635
Asset-backed securities	—		889		—		889
Mortgage-backed securities	—		1,939		—		1,939
Common stock	12,813		—		—		12,813
Private equity investments	—		—		18,222		18,222
Commingled funds	—		223,322		—		223,322
Real estate	—		—		5,755		5,755
Securities lending collateral obligation and other	—		2,615		—		2,615
Total	$	30,167	$	339,249	$	23,977	$	393,393

The following table presents the target pension asset allocations for SPS at Dec. 31 for the upcoming year:

	2014		2013
Domestic and international equity securities	39	%	29	%
Long-duration fixed income and interest rate swap securities	23		36
Short-to-intermediate term fixed income securities	14		14
Alternative investments	22		19
Cash	2		2
Total	100	%	100	%

Changes in Level 3 Plan Assets

The following tables present the changes in SPS’ Level 3 pension plan assets for the years ended Dec. 31, 2014, 2013 and 2012:

(Thousands of Dollars)	Jan. 1, 2014		Net Realized Gains (Losses)		Net Unrealized Gains (Losses)			Purchases, Issuances and Settlements, Net			Transfers Out of Level 3		Dec. 31, 2014
Private equity investments	$	18,222	$	3,101	$	(1,894	)	$	(1,098	)	$	—	$	18,331
Real estate	5,755		431		(219		)	722			—		6,689
Total	$	23,977	$	3,532	$	(2,113	)	$	(376	)	$	—	$	25,020

(Thousands of Dollars)	Jan. 1, 2013		Net Realized Gains (Losses)			Net Unrealized Gains (Losses)			Purchases, Issuances and Settlements, Net			Transfers Out of Level 3 (a)			Dec. 31, 2013
Asset-backed securities	$	1,755	$	—		$	—		$	—		$	(1,755	)	$	—
Mortgage-backed securities	4,331		—			—			—			(4,331		)	—
Private equity investments	17,049		2,630			(1,055		)	(402		)	—			18,222
Real estate	6,969		(322		)	1,475			1,128			(3,495		)	5,755
Total	$	30,104	$	2,308		$	420		$	726		$	(9,581	)	$	23,977

^(a)  Transfers out of Level 3 into Level 2 were principally due to diminished use of unobservable inputs that were previously significant to these fair value measurements and were subsequently sold during 2013.

(Thousands of Dollars)	Jan. 1, 2012		Net Realized Gains (Losses)		Net Unrealized Gains (Losses)			Purchases, Issuances and Settlements, Net			Transfers Out of Level 3		Dec. 31, 2012
Asset-backed securities	$	4,018	$	531	$	(741	)	$	(2,053	)	$	—	$	1,755
Mortgage-backed securities	7,907		245		(265		)	(3,556		)	—		4,331
Private equity investments	16,159		1,886		(2,296		)	1,300			—		17,049
Real estate	3,586		2		551			2,830			—		6,969
Total	$	31,670	$	2,664	$	(2,751	)	$	(1,479	)	$	—	$	30,104

Change in Projected Benefit Obligation

Benefit Obligations — A comparison of the actuarially computed pension benefit obligation and plan assets for SPS is presented in the following table:

(Thousands of Dollars)	2014			2013
Accumulated Benefit Obligation at Dec. 31	$	458,793		$	402,509
Change in Projected Benefit Obligation:
Obligation at Jan. 1	$	434,307		$	454,184
Service cost	9,184			9,615
Interest cost	20,444			17,908
Actuarial loss (gain)	63,209			(27,185		)
Transfer (to) from other plan	(1,939		)	3,625
Benefit payments	(24,515		)	(23,840		)
Obligation at Dec. 31	$	500,690		$	434,307

Change in Fair Value of Plan Assets

(Thousands of Dollars)	2014			2013
Change in Fair Value of Plan Assets:
Fair value of plan assets at Jan. 1	$	393,393		$	376,138
Actual return on plan assets	30,159			15,455
Employer contributions	4,869			22,015
Transfer (to) from other plan	(1,637		)	3,625
Benefit payments	(24,515		)	(23,840		)
Fair value of plan assets at Dec. 31	$	402,269		$	393,393

Funded Status of Plans

(Thousands of Dollars)	2014			2013
Funded Status of Plans at Dec. 31:
Funded status (a)	$	(98,421	)	$	(40,914	)

^(a)  Amounts are recognized in noncurrent liabilities on SPS’ balance sheets.

Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost

(Thousands of Dollars)	2014		2013
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost:
Net loss	$	252,063	$	208,594
Prior service cost	39		93
Total	$	252,102	$	208,687

Amounts Not Yet Recognized as Components of Net Periodic Benefit Costs Recorded on the Balance Sheet Based Upon Expected Recovery in Rates

(Thousands of Dollars)	2014		2013
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates:
Current regulatory assets	$	14,437	$	15,843
Noncurrent regulatory assets	237,665		192,844
Total	$	252,102	$	208,687

Schedule of Assumptions Used

Measurement date Dec. 31, 2014 Dec. 31, 2013

	2014		2013
Significant Assumptions Used to Measure Benefit Obligations:
Discount rate for year-end valuation	4.11	%	4.75	%
Expected average long-term increase in compensation level	3.75		3.75
Mortality table	RP 2014		RP 2000

	2014		2013		2012
Significant Assumptions Used to Measure Costs:
Discount rate	4.75	%	4.00	%	5.00	%
Expected average long-term increase in compensation level	3.75		3.75		4.00
Expected average long-term rate of return on assets	6.90		6.49		6.68

Components of Net Periodic Benefit Costs

Benefit Costs —The components of SPS’ net periodic pension cost were:

(Thousands of Dollars)	2014			2013			2012
Service cost	$	9,184		$	9,615		$	8,520
Interest cost	20,444			17,908			19,697
Expected return on plan assets	(26,179		)	(23,970		)	(24,928		)
Amortization of prior service cost	54			870			1,438
Amortization of net loss	13,326			17,148			12,897
Net periodic pension cost	16,829			21,571			17,624
Credits (costs) not recognized due to effects of regulation	3,170			(1,269		)	(4,300		)
Net benefit cost recognized for financial reporting	$	19,999		$	20,302		$	13,324

Postretirement Benefit Plan

Benefit Plans and Other Postretirement Benefits [Abstract]

Target Asset Allocations and Plan Assets Measured at Fair Value

The following table presents the target postretirement asset allocations for Xcel Energy Inc. and SPS at Dec. 31 for the upcoming year:

	2014		2013
Domestic and international equity securities	25	%	41	%
Short-to-intermediate fixed income securities	57		40
Alternative investments	13		13
Cash	5		6
Total	100	%	100	%

The following tables present, for each of the fair value hierarchy levels, SPS’ proportionate allocation of the total postretirement benefit plan assets that are measured at fair value as of Dec. 31, 2014 and 2013:

	Dec. 31, 2014
(Thousands of Dollars)	Level 1		Level 2			Level 3		Total
Cash equivalents (a)	$	2,513	$	—		$	—	$	2,513
Derivatives	—		18			—		18
Government securities	—		4,639			—		4,639
Insurance contracts	—		4,807			—		4,807
Corporate bonds	—		5,175			—		5,175
Asset-backed securities	—		345			—		345
Mortgage-backed securities	—		1,074			—		1,074
Commingled funds	—		26,960			—		26,960
Other	—		(175		)	—		(175		)
Total	$	2,513	$	42,843		$	—	$	45,356

	Dec. 31, 2013
(Thousands of Dollars)	Level 1		Level 2			Level 3		Total
Cash equivalents (a)	$	1,941	$	—		$	—	$	1,941
Derivatives	—		(38		)	—		(38		)
Government securities	—		5,549			—		5,549
Insurance contracts	—		5,016			—		5,016
Corporate bonds	—		4,926			—		4,926
Asset-backed securities	—		319			—		319
Mortgage-backed securities	—		2,303			—		2,303
Commingled funds	—		28,331			—		28,331
Other	—		(1,609		)	—		(1,609		)
Total	$	1,941	$	44,797		$	—	$	46,738

^(a)  Includes restricted cash of $0.1 million at Dec. 31, 2014 and 2013.

Changes in Level 3 Plan Assets

For the year ended Dec. 31, 2014 there were no assets transferred in or out of Level 3. The following tables present the changes in SPS’ Level 3 postretirement benefit plan assets for the years ended Dec. 31, 2013 and 2012:

(Thousands of Dollars)	Jan. 1, 2013		Net Realized Gains (Losses)		Net Unrealized Gains (Losses)		Purchases, Issuances and Settlements, Net		Transfers Out of Level 3 (a)			Dec. 31, 2013
Asset-backed securities	$	73	$	—	$	—	$	—	$	(73	)	$	—
Mortgage-backed securities	3,841		—		—		—		(3,841		)	—
Total	$	3,914	$	—	$	—	$	—	$	(3,914	)	$	—

^(a)  Transfers out of Level 3 into Level 2 were principally due to diminished use of unobservable inputs that were previously significant to these fair value measurements and were subsequently sold during 2013.

(Thousands of Dollars)	Jan. 1, 2012		Net Realized Gains (Losses)			Net Unrealized Gains (Losses)		Purchases, Issuances and Settlements, Net			Transfers Out of Level 3		Dec. 31, 2012
Asset-backed securities	$	730	$	(32	)	$	179	$	(804	)	$	—	$	73
Mortgage-backed securities	2,535		(70		)	377		999			—		3,841
Total	$	3,265	$	(102	)	$	556	$	195		$	—	$	3,914

Change in Projected Benefit Obligation

Benefit Obligations — A comparison of the actuarially computed benefit obligation and plan assets for SPS is presented in the following table:

(Thousands of Dollars)	2014			2013
Change in Projected Benefit Obligation:
Obligation at Jan. 1	$	54,982		$	59,260
Service cost	1,246			1,368
Interest cost	2,572			2,352
Medicare subsidy reimbursements	18			63
Plan participants’ contributions	728			698
Actuarial gain	(11,828		)	(5,215		)
Benefit payments	(3,376		)	(3,544		)
Obligation at Dec. 31	$	44,342		$	54,982

Change in Fair Value of Plan Assets

(Thousands of Dollars)	2014			2013
Change in Fair Value of Plan Assets:
Fair value of plan assets at Jan. 1	$	46,738		$	46,222
Actual return on plan assets	1,073			3,228
Plan participants’ contributions	728			698
Employer contributions	193			134
Benefit payments	(3,376		)	(3,544		)
Fair value of plan assets at Dec. 31	$	45,356		$	46,738

Funded Status of Plans

(Thousands of Dollars)	2014		2013
Funded Status of Plans at Dec. 31:
Funded status (a)	$	1,014	$	(8,244	)

^(a)  Amounts are recognized in noncurrent assets and noncurrent liabilities on SPS’ balance sheet as of Dec. 31, 2014 and 2013, respectively.

Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost

(Thousands of Dollars)	2014			2013
Amounts Not Yet Recognized as Components of Net Periodic Benefit Credit:
Net gain	$	(14,677	)	$	(5,344	)
Prior service credit	(3,432		)	(3,833		)
Total	$	(18,109	)	$	(9,177	)

Amounts Not Yet Recognized as Components of Net Periodic Benefit Costs Recorded on the Balance Sheet Based Upon Expected Recovery in Rates

(Thousands of Dollars)	2014			2013
Amounts Not Yet Recognized as Components of Net Periodic Benefit Credit Have Been Recorded as Follows Based Upon Expected Recovery in Rates:
Current regulatory liabilities	$	(892	)	$	(319	)
Noncurrent regulatory liabilities	(17,217		)	(8,858		)
Total	$	(18,109	)	$	(9,177	)

Schedule of Assumptions Used

Measurement date Dec. 31, 2014 Dec. 31, 2013

	2014		2013
Significant Assumptions Used to Measure Benefit Obligations:
Discount rate for year-end valuation	4.08	%	4.82	%
Mortality table	RP 2014		RP 2000
Health care costs trend rate — initial	6.50	%	7.00	%

	2014		2013		2012
Significant Assumptions Used to Measure Costs:
Discount rate	4.82	%	4.10	%	5.00	%
Expected average long-term rate of return on assets	7.20		7.11		6.75

Effects of One-Percent Change in Assumed Health Care Cost Trend Rate

A one-percent change in the assumed health care cost trend rate would have the following effects on SPS:

	One-Percentage Point
(Thousands of Dollars)	Increase		Decrease
APBO	$	4,555	$	(3,834	)
Service and interest components	451		(371		)

Components of Net Periodic Benefit Costs

Benefit Costs — The components of SPS’ net periodic postretirement benefit costs were:

(Thousands of Dollars)	2014			2013			2012
Service cost	$	1,246		$	1,368		$	1,259
Interest cost	2,572			2,352			2,831
Expected return on plan assets	(3,247		)	(3,183		)	(2,701		)
Amortization of transition obligation	—			—			1,545
Amortization of prior service credit	(401		)	(484		)	(148		)
Amortization of net (gain) loss	(321		)	(6		)	1,256
Net periodic postretirement benefit (credit) cost	$	(151	)	$	47		$	4,042