Retirement Benefits

9 Months Ended

Jun. 30, 2018

Retirement Benefits [Abstract]

Retirement Benefits

Retirement Benefits

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

	Pension Benefits
	Three Months Ended June 30,						Nine Months Ended June 30,
	2018			2017			2018			2017
Service cost	$	22.2		$	24.2		$	66.8		$	72.5
Interest cost	38.8			37.8			116.6			113.4
Expected return on plan assets	(61.2		)	(56.2		)	(183.9		)	(168.6		)
Amortization:
Prior service cost (credit)	0.1			(0.9		)	0.4			(2.8		)
Net actuarial loss	28.3			38.2			85.0			114.4
Settlements	—			—			—			0.2
Net periodic benefit cost	$	28.2		$	43.1		$	84.9		$	129.1

	Other Postretirement Benefits
	Three Months Ended June 30,						Nine Months Ended June 30,
	2018			2017			2018			2017
Service cost	$	0.4		$	0.3		$	1.0		$	1.0
Interest cost	0.6			0.7			1.8			1.9
Amortization:
Prior service credit	(1.4		)	(1.5		)	(4.1		)	(4.5		)
Net actuarial loss	0.4			0.6			1.3			1.7
Net periodic benefit cost	$	—		$	0.1		$	—		$	0.1