Defined Benefit Pension and Other Postretirement Plans (Tables)

9 Months Ended

Jun. 30, 2014

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Components of Net Periodic Pension Expense and Other Postretirement Benefit Costs

Net periodic pension expense and other postretirement benefit costs include the following components:

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended June 30,						Three Months Ended June 30,
	2014			2013			2014			2013
Service cost	$	2.3		$	2.8		$	0.1		$	0.2
Interest cost	6.5			5.9			0.2			0.2
Expected return on assets	(7.3		)	(6.9		)	(0.1		)	(0.1		)
Amortization of:
Prior service cost (benefit)	0.1			0.1			(0.1		)	(0.1		)
Actuarial loss	1.9			3.7			—			0.1
Net benefit cost	3.5			5.6			0.1			0.3
Change in associated regulatory liabilities	—			—			0.9			0.8
Net expense	$	3.5		$	5.6		$	1.0		$	1.1
	Pension Benefits						Other Postretirement Benefits
	Nine Months Ended						Nine Months Ended
	June 30,						June 30,
	2014			2013			2014			2013
Service cost	$	7.0		$	8.5		$	0.4		$	0.5
Interest cost	19.4			17.6			0.7			0.7
Expected return on assets	(22.0		)	(20.7		)	(0.4		)	(0.4		)
Amortization of:
Prior service cost (benefit)	0.2			0.2			(0.4		)	(0.2		)
Actuarial loss	5.7			11.2			0.1			0.3
Net benefit cost	10.3			16.8			0.4			0.9
Change in associated regulatory liabilities	—			—			2.7			2.4
Net expense	$	10.3		$	16.8		$	3.1		$	3.3