Retirement Plans (Tables)

6 Months Ended

Mar. 31, 2020

Defined Benefit Plan [Abstract]

Schedule of Net Periodic Benefit Cost

The components of net periodic benefit cost for our pension plans are presented below.

	Three months ended				Six months ended
	March 31,				March 31,
	2020		2019		2020		2019
	(in millions)
Service cost	$	0.4	$	0.4	$	0.8	$	0.8
Pension costs (benefits) other than service:
Interest cost	2.8		3.5		5.6		7.0
Expected return on plan assets	(4.2)		(4.0)		(8.4)		(8.1)
Amortization of actuarial net loss	0.6		0.5		1.3		1.0
Curtailment/special settlement loss (gain)	—		1.0		—		1.0
Pension costs (benefits) other than service	(0.8)		1.0		(1.5)		0.9
Net periodic (benefit) cost	$	(0.4)	$	1.4	$	(0.7)	$	1.7