Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2021

Postretirement Plan

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Defined Benefit Plans Disclosures

The following table sets forth the net periodic benefit cost for the Company’s other postretirement benefit plans. The amounts for the three and six months ended June 30, 2021 are based on calculations prepared by the Company's actuaries and represent the Company’s best estimate of that period’s proportionate share of the amounts to be recorded for the year ending December 31, 2021.

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Components of net periodic benefit credit:
Service cost	$	0.1	$	0.1	$	0.1	$	0.1
Interest cost	0.3		0.5		0.7		1.0
Expected return on plan assets	—		(0.1)		—		(0.2)
Amortization of prior service credit	(2.5)		(2.5)		(5.0)		(4.9)
Net periodic benefit credit	$	(2.1)	$	(2.0)	$	(4.2)	$	(4.0)