Pension and Other Postretirement Benefits

The components of the net periodic benefit cost related to the Company’s pension and other postretirement benefits for the three and nine months ended March 31, 2018 and 2017 were as follows:



Three months ended March 31,	Pension Plans						Other Postretirement Plans
($ in millions)	2018			2017			2018			2017
Service cost	$	2.4		$	2.2		$	0.7		$	0.9
Interest cost	13.0			12.4			2.4			2.3
Expected return on plan assets	(16.5		)	(16.6		)	(1.7		)	(1.7		)
Amortization of net loss	3.4			9.5			0.7			0.8
Amortization of prior service cost (benefit)	0.5			0.5			(1.3		)	(1.6		)
Net periodic benefit costs	$	2.8		$	8.0		$	0.8		$	0.7



Nine months ended March 31,	Pension Plans						Other Postretirement Plans
($ in millions)	2018			2017			2018			2017
Service cost	$	7.1		$	18.1		$	2.0		$	2.8
Interest cost	39.1			37.8			7.2			6.9
Expected return on plan assets	(49.5		)	(48.4		)	(5.2		)	(5.1		)
Amortization of net loss	10.2			28.3			2.2			2.4
Amortization of prior service cost (benefit)	1.5			1.3			(4.0		)	(4.9		)
Curtailment charge	—			0.5			—			—
Net periodic benefit costs	$	8.4		$	37.6		$	2.2		$	2.1

In September 2016, the Company announced changes to retirement plans it offers to certain employees. Benefits accrued to eligible participants of its largest qualified defined benefit pension plan and certain non-qualified benefit plans were frozen effective December 31, 2016. The Company recognized the plan freeze in the three months ended September 30, 2016 as a curtailment, since the plan changes eliminated the accrual of defined benefits for future services for a significant number of participants. The impact of the curtailment included a one-time accelerated recognition of outstanding unamortized prior service costs of $0.5 million, which was recognized in the three months ended September 30, 2016.

During the nine months ended March 31, 2018 and 2017, the Company made $5.7 million and $100.0 million, respectively, of contributions to its qualified defined benefit pension plans. The Company currently expects to contribute $1.0 million to its qualified defined benefit pension plans during the remainder of fiscal year 2018.