EMPLOYEE BENEFIT PLANS

Net periodic pension and postretirement benefit cost for the Company’s defined pension and postretirement benefit plans for the three months ended March 31, 2018 and 2017 are set forth below (in millions):



	Three Months Ended March 31,
Pension benefits	2018			2017
Service cost	$	4.9		$	4.2
Interest cost	5.1			5.0
Expected return on plan assets	(9.4		)	(8.7		)
Amortization of net actuarial losses	3.1			3.0
Amortization of prior service cost	0.3			0.3
Net periodic pension cost	$	4.0		$	3.8



	Three Months Ended March 31,
Postretirement benefits	2018		2017
Interest cost	$	0.4	$	0.4
Amortization of prior service cost	0.1		0.1
Net periodic postretirement benefit cost	$	0.5	$	0.5

The components of net periodic pension and postretirement benefits cost, other than the service cost component, are included in “other expense, net” in the Company’s Condensed Consolidated Statements of Operations. Refer to Note 1 for further information.

The following table summarizes the activity in accumulated other comprehensive loss related to the Company’s defined pension and postretirement benefit plans during the three months ended March 31, 2018 (in millions):



	Before-Tax Amount			Income Tax			After-Tax Amount
Accumulated other comprehensive loss as of December 31, 2017	$	(380.6	)	$	(95.5	)	$	(285.1	)
Amortization of net actuarial losses	3.1			0.4			2.7
Amortization of prior service cost	0.4			—			0.4
Accumulated other comprehensive loss as of March 31, 2018	$	(377.1	)	$	(95.1	)	$	(282.0	)

During the three months ended March 31, 2018, approximately $9.9 million of contributions had been made to the Company’s defined pension benefit plans. The Company currently estimates its minimum contributions for 2018 to its defined pension benefit plans will aggregate approximately $32.5 million.

During the three months ended March 31, 2018, the Company made approximately $0.4 million of contributions to its postretirement health care and life insurance benefit plans. The Company currently estimates that it will make approximately $1.6 million of contributions to its postretirement health care and life insurance benefit plans during 2018.