The details of net periodic benefit cost, before consideration of capitalized amounts, of the Company's Pension Plan, the Restoration of Retirement Income Plan and the postretirement benefit plans included in the Condensed Consolidated Financial Statements are as follows:

Net Periodic Benefit Cost



	Pension Plan												Restoration of Retirement Income Plan
	Three Months Ended						Six Months Ended						Three Months Ended				Six Months Ended
	June 30,						June 30,						June 30,				June 30,
(In millions)	2017 (A)			2016 (A)			2017 (B)			2016 (B)			2017 (A)		2016 (A)		2017 (B)		2016 (B)
Service cost	$	3.5		$	3.5		$	7.7		$	7.9		$	0.1	$	0.1	$	0.2	$	0.2
Interest cost	6.6			6.1			13.1			12.7			—		0.1		0.1		0.2
Expected return on plan assets	(10.6		)	(10.2		)	(21.3		)	(20.7		)	—		—		—		—
Amortization of net loss	4.7			4.0			8.7			8.2			0.1		0.1		0.2		0.3
Settlement	—			—			—			—			—		8.7		—		8.7
Total net periodic benefit cost	4.2			3.4			8.2			8.1			0.2		9.0		0.5		9.4
Less: Amount paid by unconsolidated affiliates	0.9			1.2			1.7			2.5			—		0.2		—		0.2
Net periodic benefit cost (net of unconsolidated affiliates)	$	3.3		$	2.2		$	6.5		$	5.6		$	0.2	$	8.8	$	0.5	$	9.2


(A)	In addition to the $3.5 million and $11.0 million of net periodic benefit cost recognized during the three months ended June 30, 2017 and 2016, respectively, OG&E recognized the following:


•	an increase in pension expense during the three months ended June 30, 2017 and 2016 of $2.9 million and $2.6 million, respectively, to maintain the allowable amount to be recovered for pension expense in the Oklahoma jurisdiction, which are included in the pension tracker regulatory liability (See Note 1.);


•	a deferral of pension expense during the three months ended June 30, 2017 of $2.3 million related to the Arkansas jurisdictional portion of the pension settlement charge of $22.4 million in 2013;


•	a deferral of pension expense during the three months ended June 30, 2016 of $0.6 million related to the pension settlement charge of $8.7 million, in accordance with the Oklahoma pension tracker regulatory liability (See Note 1.); and


•	a deferral of pension expense during the three months ended June 30, 2016 of $0.1 million related to the Arkansas jurisdictional portion of the pension settlement charge of $8.7 million.


(B)	In addition to the $7.0 million and $14.8 million of net periodic benefit cost recognized during the six months ended June 30, 2017 and 2016, respectively, OG&E recognized the following:


•	an increase in pension expense during the six months ended June 30, 2017 and 2016 of $5.8 million and $4.9 million, respectively, to maintain the allowable amount to be recovered for pension expense in the Oklahoma jurisdiction, which are included in the pension tracker regulatory liability (See Note 1.);


•	a deferral of pension expense during the six months ended June 30, 2017 of $2.3 million related to the Arkansas jurisdictional portion of the pension settlement charge of $22.4 million in 2013;


•	a deferral of pension expense during the six months ended June 30, 2016 of $0.6 million related to the pension settlement charge of $8.7 million, in accordance with the Oklahoma pension tracker regulatory liability (See Note 1.); and


•	a deferral of pension expense during the six months ended June 30, 2016 of $0.1 million related to the Arkansas jurisdictional portion of the pension settlement charge of $8.7 million.



	Postretirement Benefit Plans
	Three Months Ended						Six Months Ended
	June 30,						June 30,
(In millions)	2017 (B)			2016 (B)			2017 (C)			2016 (C)
Service cost	$	0.2		$	0.1		$	0.4		$	0.4
Interest cost	2.1			2.4			4.3			4.7
Expected return on plan assets	(0.5		)	(0.5		)	(1.1		)	(1.1		)
Amortization of net loss	0.2			0.8			0.8			1.3
Amortization of unrecognized prior service cost (A)	—			(2.2		)	—			(4.4		)
Total net periodic benefit cost	2.0			0.6			4.4			0.9
Less: Amount paid by unconsolidated affiliates	0.2			—			0.6			0.1
Net periodic benefit cost (net of unconsolidated affiliates)	$	1.8		$	0.6		$	3.8		$	0.8


(A)	Unamortized prior service cost is amortized on a straight-line basis over the average remaining service period to the first eligibility age of participants who are expected to receive a benefit and are active at the date of the plan amendment.

(B)

In addition to the $1.8 million and $0.6 million of net periodic benefit cost recognized during the three months ended June 30, 2017 and 2016, respectively, OG&E recognized an increase in postretirement medical expense in the three months ended June 30, 2017 and 2016 of $1.0 million and $2.0 million, respectively, to maintain the allowable amount to be recovered for postretirement medical expense in the Oklahoma jurisdiction which are included in the pension tracker regulatory liability (See Note 1.).

(C)

In addition to the $3.8 million and $0.8 million of net periodic benefit cost recognized during the six months ended June 30, 2017 and 2016, respectively, OG&E recognized an increase in postretirement medical expense in the six months ended June 30, 2017 and 2016 of $2.1 million and $4.0 million, respectively, to maintain the allowable amount to be recovered for postretirement medical expense in the Oklahoma jurisdiction which are included in the pension tracker regulatory liability (See Note 1.).