Retirement Plans (Tables)

3 Months Ended

Dec. 31, 2019

Retirement Plans [Abstract]

Summary of Components of Net Pension Income and Summary of Components of Postretirement Benefit Cost

The following table presents a summary of the components of net pension income (in millions):

	Three Months Ended
	December 31,
	2019			2018
Service cost	$	13.1		$	10.9
Interest cost		49.9			56.5
Expected return on plan assets		(90.8	)		(82.9	)
Amortization of net actuarial loss		11.9			7.0
Amortization of prior service cost		1.4			1.3
Company defined benefit plan income		(14.5	)		(7.2	)
Multiemployer and other plans		0.3			0.2
Net pension income	$	(14.2	)	$	(7.0	)

The following table presents a summary of the components of the net postretirement cost (in millions):

	Three Months Ended
	December 31,
	2019			2018
Service cost	$	0.4		$	0.3
Interest cost		1.8			1.9
Amortization of net actuarial gain		(0.2	)		(0.4	)
Amortization of prior service credit		(0.7	)		(0.7	)
Net postretirement cost	$	1.3		$	1.1