Pension and Other Postretirement Plans

6 Months Ended

Jun. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Pension and Other Postretirement Plans - MGE Energy and MGE.

MGE maintains qualified and nonqualified pension plans, health care, and life insurance benefits. Additionally, MGE has defined contribution 401(k) benefit plans. MGE refined its methodology for using discount rates to measure the components of net periodic benefit cost for 2016. The refined methodology uses individual spot rates, instead of a weighted average of the yield curve spot rates, for measuring the service cost and interest cost components.

The following table presents the components of MGE Energy's and MGE's net periodic benefit costs recognized for the three and six months ended June 30, 2016 and 2015. A portion of the net periodic benefit cost is capitalized within the consolidated balance sheets.

		Three Months Ended				Six Months Ended
		June 30,				June 30,
(In thousands)		2016		2015		2016		2015
Pension Benefits
Components of net periodic cost:
Service cost	$	1,564	$	2,039	$	2,945	$	3,837
Interest cost		3,494		3,902		6,583		7,342
Expected return on assets		(6,329)		(6,438)		(11,922)		(12,115)
Amortization of:
Prior service cost		3		6		5		12
Actuarial loss		1,534		1,513		2,890		2,847
Net periodic cost	$	266	$	1,022	$	501	$	1,923

Postretirement Benefits
Components of net periodic (benefit) cost:
Service cost	$	399	$	3	$	723	$	386
Interest cost		831		6		1,505		784
Expected return on assets		(868)		(5)		(1,573)		(708)
Amortization of:
Transition obligation		1		-		2		1
Prior service benefit		(822)		(5)		(1,489)		(672)
Actuarial loss		196		2		355		264
Net periodic (benefit) cost	$	(263)	$	1	$	(477)	$	55