Retirement Benefits (Tables)

9 Months Ended

Jun. 30, 2019

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

The components of net periodic benefit cost are (in millions):

	Pension Benefits
	Three Months Ended June 30,						Nine Months Ended June 30,
	2019			2018			2019			2018
Service cost	$	19.6		$	22.2		$	58.7		$	66.8
Interest cost	39.6			38.8			118.8			116.6
Expected return on plan assets	(61.2		)	(61.2		)	(183.6		)	(183.9		)
Amortization:
Prior service cost	0.3			0.1			0.9			0.4
Net actuarial loss	19.4			28.3			58.4			85.0
Settlements	(0.2		)	—			(0.6		)	—
Net periodic benefit cost	$	17.5		$	28.2		$	52.6		$	84.9

	Other Postretirement Benefits
	Three Months Ended June 30,						Nine Months Ended June 30,
	2019			2018			2019			2018
Service cost	$	0.2		$	0.4		$	0.7		$	1.0
Interest cost	0.7			0.6			1.8			1.8
Amortization:
Prior service credit	(1.4		)	(1.4		)	(4.1		)	(4.1		)
Net actuarial loss	0.2			0.4			0.6			1.3
Net periodic benefit credit	$	(0.3	)	$	—		$	(1.0	)	$	—