Retirement Plans (Tables)

9 Months Ended

Jun. 30, 2020

Retirement Plans [Abstract]

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

Pension and Postretirement Income / Expense

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

	Three Months Ended						Nine Months Ended
	June 30,						June 30,
	2020			2019			2020			2019
Service cost	$	11.9		$	10.2		$	39.2		$	32.5
Interest cost		49.7			58.8			149.1			174.0
Expected return on plan assets		(90.1	)		(85.9	)		(271.7	)		(254.7	)
Amortization of net actuarial loss		11.4			6.3			35.1			18.7
Amortization of prior service cost		1.9			1.3			5.4			3.9
Curtailment loss		—			0.1			0.4			1.0
Company defined benefit plan income		(15.2	)		(9.2	)		(42.5	)		(24.6	)
Multiemployer pension withdrawal income		(2.0	)		(1.7	)		(1.1	)		(1.7	)
Multiemployer and other plans		0.3			0.2			1.0			0.5
Net pension income	$	(16.9	)	$	(10.7	)	$	(42.6	)	$	(25.8	)

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

	Three Months Ended						Nine Months Ended
	June 30,						June 30,
	2020			2019			2020			2019
Service cost	$	0.3		$	0.2		$	1.0		$	0.8
Interest cost		1.7			1.9			5.3			5.8
Amortization of net actuarial loss (gain)		0.5			(0.7	)		0.1			(1.5	)
Amortization of prior service credit		(0.7	)		(0.7	)		(2.1	)		(2.1	)
Net postretirement cost	$	1.8		$	0.7		$	4.3		$	3.0