Retirement Benefits (Tables)

9 Months Ended

Jun. 30, 2017

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Benefit Costs

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

	Pension Benefits
	Three Months Ended June 30,						Nine Months Ended June 30,
	2017			2016			2017			2016
Service cost	$	24.2		$	22.1		$	72.5		$	66.0
Interest cost	37.8			42.5			113.4			127.2
Expected return on plan assets	(56.2		)	(54.8		)	(168.6		)	(163.9		)
Amortization:
Prior service credit	(0.9		)	(0.7		)	(2.8		)	(2.1		)
Net actuarial loss	38.2			31.2			114.4			93.4
Settlements	—			—			0.2			—
Net periodic benefit cost	$	43.1		$	40.3		$	129.1		$	120.6

	Other Postretirement Benefits
	Three Months Ended June 30,						Nine Months Ended June 30,
	2017			2016			2017			2016
Service cost	$	0.3		$	0.4		$	1.0		$	1.0
Interest cost	0.7			0.8			1.9			2.5
Amortization:
Prior service credit	(1.5		)	(2.8		)	(4.5		)	(8.5		)
Net actuarial loss	0.6			0.6			1.7			1.9
Net periodic benefit cost (income)	$	0.1		$	(1.0	)	$	0.1		$	(3.1	)