Benefit Plans and Other Postretirement Benefits (Tables)

12 Months Ended

Dec. 31, 2013

Benefit Plans and Other Postretirement Benefits [Abstract]

Projected Benefit Payments for the Pension and Postretirement Benefit Plans

The following table lists NSP-Wisconsin’s projected benefit payments for the pension and postretirement benefit plans:

(Thousands of Dollars)	ProjectedPension BenefitPayments		Gross Projected Postretirement Health Care BenefitPayments		ExpectedMedicare Part DSubsidies		Net Projected Postretirement Health Care BenefitPayments
2014	$	21,677	$	1,491	$	27	$	1,464
2015	14,257		1,459		25		1,434
2016	13,420		1,444		24		1,420
2017	13,851		1,384		20		1,364
2018	12,983		1,357		18		1,339
2019-2023	64,935		6,229		82		6,147

Contributions to Multiemployer Plans

Contributions to multiemployer plans were as follows for the years ended Dec. 31, 2013, 2012 and 2011.  There were no significant changes to the nature or magnitude of the participation of NSP-Wisconsin in multiemployer plans for the years presented:

(Thousands of Dollars)	2013		2012		2011
Multiemployer plan contributions:
Pension	$	130	$	163	$	169
Total	$	130	$	163	$	169

Pension Plans

Benefit Plans and Other Postretirement Benefits [Abstract]

Target Asset Allocations and Plan Assets Measured at Fair Value

The following table presents the target pension asset allocations for NSP-Wisconsin:

	2013		2012
Domestic and international equity securities	31	%	29	%
Long-duration fixed income and interest rate swap securities	29		30
Short-to-intermediate term fixed income securities	16		12
Alternative investments	22		27
Cash	2		2
Total	100	%	100	%

The following tables present, for each of the fair value hierarchy levels, NSP-Wisconsin’s pension plan assets that are measured at fair value as of Dec. 31, 2013 and 2012:

	Dec. 31, 2013
(Thousands of Dollars)	Level 1		Level 2		Level 3		Total
Cash equivalents	$	4,332	$	—	$	—	$	4,332
Derivatives	—		937		—		937
Government securities	—		6,711		—		6,711
Corporate bonds	—		24,955		—		24,955
Asset-backed securities	—		307		—		307
Mortgage-backed securities	—		684		—		684
Common stock	4,533		—		—		4,533
Private equity investments	—		—		7,502		7,502
Commingled funds	—		84,364		—		84,364
Real estate	—		—		2,299		2,299
Securities lending collateral obligation and other	—		311		—		311
Total	$	8,865	$	118,269	$	9,801	$	136,935

	Dec. 31, 2012
(Thousands of Dollars)	Level 1		Level 2			Level 3		Total
Cash equivalents	$	7,956	$	—		$	—	$	7,956
Derivatives	—		390			—		390
Government securities	—		9,406			—		9,406
Corporate bonds	—		25,046			—		25,046
Asset-backed securities	—		—			749		749
Mortgage-backed securities	—		—			2,128		2,128
Common stock	3,977		—			—		3,977
Private equity investments	—		—			8,545		8,545
Commingled funds	—		76,398			—		76,398
Real estate	—		—			3,472		3,472
Securities lending collateral obligation and other	—		(1,521		)	—		(1,521		)
Total	$	11,933	$	109,719		$	14,894	$	136,546

Changes in Level 3 Plan Assets

The following tables present the changes in NSP-Wisconsin’s Level 3 pension plan assets for the years ended Dec. 31, 2013, 2012 and 2011:

(Thousands of Dollars)	Jan. 1, 2013		Net Realized Gains (Losses)			Net Unrealized Gains (Losses)			Purchases, Issuances and Settlements, Net			Transfer Out of Level 3 (a)			Dec. 31, 2013
Asset-backed securities	$	749	$	—		$	—		$	—		$	(749	)	$	—
Mortgage-backed securities	2,128		—			—			—			(2,128		)	—
Private equity investments	8,545		1,083			(1,960		)	(166		)	—			7,502
Real estate	3,472		(129		)	247			450			(1,741		)	2,299
Total	$	14,894	$	954		$	(1,713	)	$	284		$	(4,618	)	$	9,801

^(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	$	1,578	$	197	$	(273	)	$	(753	)	$	—	$	749
Mortgage-backed securities	3,781		93		(112		)	(1,634		)	—		2,128
Private equity investments	8,440		945		(1,197		)	357			—		8,545
Real estate	2,008		1		328			1,135			—		3,472
Total	$	15,807	$	1,236	$	(1,254	)	$	(895	)	$	—	$	14,894

(Thousands of Dollars)	Jan. 1, 2011		Net Realized Gains (Losses)			Net Unrealized Gains (Losses)			Purchases, Issuances and Settlements, Net			Transfers Out of Level 3		Dec. 31, 2011
Asset-backed securities	$	1,367	$	121		$	(125	)	$	215		$	—	$	1,578
Mortgage-backed securities	5,984		55			(295		)	(1,963		)	—		3,781
Private equity investments	6,704		210			648			878			—		8,440
Real estate	3,746		(34		)	1,002			(2,706		)	—		2,008
Total	$	17,801	$	352		$	1,230		$	(3,576	)	$	—	$	15,807

Change in Projected Benefit Obligation

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

(Thousands of Dollars)	2013			2012
Accumulated Benefit Obligation at Dec. 31	$	153,894		$	169,939
Change in Projected Benefit Obligation:
Obligation at Jan. 1	$	179,995		$	159,766
Service cost	5,682			4,568
Interest cost	6,924			7,765
Plan amendments	(1,109		)	216
Actuarial (gain) loss	(11,097		)	21,083
Benefit payments	(16,465		)	(13,403		)
Obligation at Dec. 31	$	163,930		$	179,995

Change in Fair Value of Plan Assets

(Thousands of Dollars)	2013			2012
Change in Fair Value of Plan Assets:
Fair value of plan assets at Jan. 1	$	136,546		$	121,348
Actual return on plan assets	5,525			16,079
Employer contributions	11,329			12,522
Benefit payments	(16,465		)	(13,403		)
Fair value of plan assets at Dec. 31	$	136,935		$	136,546

Funded Status of Plans

(Thousands of Dollars)	2013			2012
Funded Status of Plans at Dec. 31:
Funded status (a)	$	(26,995	)	$	(43,449	)

^(a)  Amounts are recognized in noncurrent liabilities on NSP-Wisconsin’s consolidated balance sheets.

Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost

(Thousands of Dollars)	2013		2012
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost:
Net loss	$	84,773	$	99,338
Prior service cost	778		2,290
Total	$	85,551	$	101,628

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)	2013		2012
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	$	7,631	$	6,895
Noncurrent regulatory assets	77,920		94,733
Total	$	85,551	$	101,628

Schedule of Assumptions Used

	2013		2012		2011
Significant Assumptions Used to Measure Costs:
Discount rate	4.00	%	5.00	%	5.50	%
Expected average long-term increase in compensation level	3.75		4.00		4.00
Expected average long-term rate of return on assets	7.25		7.50		8.00

Measurement date Dec. 31, 2013 Dec. 31, 2012

	2013		2012
Significant Assumptions Used to Measure Benefit Obligations:
Discount rate for year-end valuation	4.75	%	4.00	%
Expected average long-term increase in compensation level	3.75		3.75
Mortality table	RP 2000		RP 2000

Components of Net Periodic Benefit Costs

Benefit Costs —The components of NSP-Wisconsin’s net periodic pension cost were:

(Thousands of Dollars)	2013			2012			2011
Service cost	$	5,682		$	4,568		$	4,271
Interest cost	6,924			7,765			8,031
Expected return on plan assets	(9,995		)	(10,489		)	(11,484		)
Amortization of prior service cost	417			1,771			1,895
Amortization of net loss	7,924			6,004			4,070
Net periodic pension cost	$	10,952		$	9,619		$	6,783

Postretirement Benefit Plan

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, NSP-Wisconsin’s postretirement benefit plan assets that are measured at fair value as of Dec. 31, 2013 and 2012:

	Dec. 31, 2013
(Thousands of Dollars)	Level 1		Level 2			Level 3		Total
Cash equivalents	$	31	$	—		$	—	$	31
Derivatives	—		(2		)	—		(2		)
Government securities	—		89			—		89
Insurance contracts	—		80			—		80
Corporate bonds	—		79			—		79
Asset-backed securities	—		5			—		5
Mortgage-backed securities	—		37			—		37
Commingled funds	—		452			—		452
Other	—		(25		)	—		(25		)
Total	$	31	$	715		$	—	$	746

	Dec. 31, 2012
(Thousands of Dollars)	Level 1		Level 2			Level 3		Total
Cash equivalents	$	123	$	—		$	—	$	123
Government securities	—		99			—		99
Insurance contracts	—		67			—		67
Corporate bonds	—		59			—		59
Asset-backed securities	—		—			1		1
Mortgage-backed securities	—		—			54		54
Commingled funds	—		307			—		307
Other	—		(63		)	—		(63		)
Total	$	123	$	469		$	55	$	647

Changes in Level 3 Plan Assets

The following tables present the changes in NSP-Wisconsin’s Level 3 postretirement benefit plan assets for the years ended Dec. 31, 2013, 2012 and 2011:

(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	$	—	$	—	$	—	$	(1	)	$	—
Mortgage-backed securities	54		—		—		—		(54		)	—
Total	$	55	$	—	$	—	$	—	$	(55	)	$	—

^(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	$	14	$	—		$	3	$	(16	)	$	—	$	1
Mortgage-backed securities	48		(1		)	6		1			—		54
Total	$	62	$	(1	)	$	9	$	(15	)	$	—	$	55

(Thousands of Dollars)	Jan. 1, 2011		Net Realized Gains (Losses)			Net Unrealized Gains (Losses)			Purchases, Issuances and Settlements, Net		Transfers Out of Level 3		Dec. 31, 2011
Asset-backed securities	$	6	$	—		$	(2	)	$	10	$	—	$	14
Mortgage-backed securities	45		(3		)	6			—		—		48
Total	$	51	$	(3	)	$	4		$	10	$	—	$	62

Change in Projected Benefit Obligation

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

(Thousands of Dollars)	2013			2012
Change in Projected Benefit Obligation:
Obligation at Jan. 1	$	19,432		$	22,127
Service cost	25			20
Interest cost	760			1,075
Medicare subsidy reimbursements	31			189
Plan amendments	—			(3,440		)
Plan participants’ contributions	621			893
Actuarial (gain) loss	(1,724		)	1,486
Benefit payments	(1,992		)	(2,918		)
Obligation at Dec. 31	$	17,153		$	19,432

Change in Fair Value of Plan Assets

(Thousands of Dollars)	2013			2012
Change in Fair Value of Plan Assets:
Fair value of plan assets at Jan. 1	$	647		$	746
Actual return on plan assets	(13		)	3
Plan participants’ contributions	621			893
Employer contributions	1,483			1,923
Benefit payments	(1,992		)	(2,918		)
Fair value of plan assets at Dec. 31	$	746		$	647

Funded Status of Plans

(Thousands of Dollars)	2013			2012
Funded Status of Plans at Dec. 31:
Funded status	$	(16,407	)	$	(18,785	)
Current liabilities	(718		)	(943		)
Noncurrent liabilities	(15,689		)	(17,842		)
Net postretirement amounts recognized on consolidated balance sheets	$	(16,407	)	$	(18,785	)

Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost

(Thousands of Dollars)	2013			2012
Amounts Not Yet Recognized as Components of Net Periodic Cost:
Net loss	$	11,098		$	13,730
Prior service credit	(3,187		)	(3,538		)
Transition obligation	—			1
Total	$	7,911		$	10,193

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)	2013		2012
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	$	570	$	433
Noncurrent regulatory assets	7,341		9,760
Total	$	7,911	$	10,193

Schedule of Assumptions Used

Measurement date Dec. 31, 2013 Dec. 31, 2012

	2013		2012
Significant Assumptions Used to Measure Benefit Obligations:
Discount rate for year-end valuation	4.82	%	4.10	%
Mortality table	RP 2000		RP 2000
Health care costs trend rate — initial	7.00	%	7.50	%

	2013		2012		2011
Significant Assumptions Used to Measure Costs:
Discount rate	4.10	%	5.00	%	5.50	%
Expected average long-term rate of return on assets	7.11		6.75		7.50

Components of Net Periodic Benefit Costs

Benefit Costs — The components of NSP-Wisconsin’s net periodic postretirement benefit cost were:

(Thousands of Dollars)	2013			2012			2011
Service cost	$	25		$	20		$	17
Interest cost	760			1,075			1,144
Expected return on plan assets	(42		)	(50		)	(74		)
Amortization of transition obligation	1			171			171
Amortization of prior service credit	(351		)	(14		)	(14		)
Amortization of net loss	963			486			366
Net periodic postretirement benefit cost	$	1,356		$	1,688		$	1,610

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 NSP-Wisconsin:

	One-Percentage Point
(Thousands of Dollars)	Increase		Decrease
APBO	$	1,773	$	(1,486	)
Service and interest components	78		(61		)