7. Employee Benefits

The components of the estimated net pension and other postretirement benefits plan income for the three months ended March 31, 2018 and 2017 were as follows:

	Three Months Ended
	March 31,
	2018			2017
Pension expense (income):
Service cost	$	0.2		$	0.2
Interest cost		7.8			7.8
Expected return on plan assets		(12.6	)		(12.3	)
Amortization, net		2.0			1.7
Settlements		0.3			—
Net pension income	$	(2.3	)	$	(2.6	)

Other postretirement benefits plan expense (income):
Service cost	$	0.4		$	0.3
Interest cost		2.6			2.8
Expected return on plan assets		(3.5	)		(3.4	)
Amortization, net		(0.7	)		(0.7	)
Net other postretirement benefit income	$	(1.2	)	$	(1.0	)

During the three months ended March 31, 2018, the Company contributed $6.3 million to its benefit plans.

The Company adopted ASU No. 2017-07 “Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost”, with retrospective adoption, during the first quarter of 2018 and records benefit service costs in cost of sales and selling, general and administrative expenses. The other components, which include interest cost, expected return on plan assets, net amortization and settlements, are recorded in Investment and other (income) expense-net within the Condensed Consolidated Statements of Operations. Previously, all pension and postretirement benefits expense (income) was recorded in cost of sales and selling, general and administrative expenses. See Note 16, New Accounting Pronouncements, for further discussion and impact of adoption.