Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2018

Compensation And Retirement Disclosure [Abstract]

Components of Net Periodic Cost for Defined Benefit Pension Plan and Other Postretirement Benefit Plan

The components of net periodic cost for our defined benefit pension plan and for our postretirement benefit plan are included in the following tables:

	Three Months Ended September 30,						Nine Months Ended September 30,
Net Periodic Pension Cost	2018			2017			2018			2017
Interest cost	$	4.1		$	4.3		$	12.3		$	12.9
Actuarial loss amortization		3.6			3.2			10.8			9.6
Less: Expected return on plan assets		(6.5	)		(6.6	)		(19.5	)		(19.8	)
Net periodic pension cost	$	1.2		$	0.9		$	3.6		$	2.7

	Three Months Ended September 30,						Nine Months Ended September 30,
Net Periodic Postretirement Benefit	2018			2017			2018			2017
Service benefit	$	(0.1	)	$	(0.1	)	$	(0.3	)	$	(0.3	)
Interest cost		0.1			0.1			0.3			0.3
Actuarial gain amortization		(0.6	)		(0.6	)		(1.8	)		(1.8	)
Net periodic postretirement benefit gain	$	(0.6	)	$	(0.6	)	$	(1.8	)	$	(1.8	)