Retirement Plans (Tables)

9 Months Ended

Jun. 30, 2019

Retirement Plans [Abstract]

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

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

	Three Months Ended						Nine Months Ended
	June 30,						June 30,
	2019			2018			2019			2018
Service cost	$	10.2		$	9.4		$	32.5		$	33.5
Interest cost		58.8			51.5			174.0			153.7
Expected return on plan assets		(85.9	)		(82.1	)		(254.7	)		(246.7	)
Amortization of net actuarial loss		6.3			6.7			18.7			15.9
Amortization of prior service cost		1.3			1.3			3.9			3.5
Curtailment loss		0.1			—			1.0			—
Company defined benefit plan income		(9.2	)		(13.2	)		(24.6	)		(40.1	)
Multiemployer pension withdrawals		(1.7	)		4.2			(1.7	)		184.2
Multiemployer and other plans		0.2			0.2			0.5			1.3
Net pension (income) cost	$	(10.7	)	$	(8.8	)	$	(25.8	)	$	145.4

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,
	2019			2018			2019			2018
Service cost	$	0.2		$	0.4		$	0.8		$	1.2
Interest cost		1.9			2.1			5.8			6.1
Amortization of net actuarial (gain) loss		(0.7	)		0.3			(1.5	)		0.2
Amortization of prior service credit		(0.7	)		(1.1	)		(2.1	)		(3.2	)
Net postretirement cost	$	0.7		$	1.7		$	3.0		$	4.3