Employee Benefit Plans and Other Postretirement Benefits (Tables)

3 Months Ended

Mar. 31, 2021

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Benefit Costs

The components of net periodic benefit cost for our pension plans were as follows (dollars in millions):

	Pension Plans
	Three Months Ended March 31,
	2021			2020
Service cost	$	5.4		$	5.9
Interest cost		7.4			10.0
Expected return on plan assets		(15.8	)		(14.2	)
Net amortization of unrecognized amounts
Prior service cost		1.0			1.1
Actuarial loss		2.5			2.7
Net periodic benefit cost	$	0.5		$	5.5