Retirement And Postretirement Benefit Plans (Schedule Of Change In The Accumulated Postretirement Benefit Obligation) (Details) (USD $) In Millions	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Service cost	$ 5.2	$ 5.1	$ 4.0
Interest cost	13.2	13.2	13.3
Accrued benefits obligation, long-term	87.4	59.0
Postretirement Health Care Plan [Member]
Benefit obligation at beginning of year	9.7	9.7
Service cost	0.4	0.4
Interest cost	0.4	0.5
Actuarial loss	(0.6)	0.1
Benefits paid	(0.7)	(1.3)
Retiree contributions	0.3	0.3
Benefit obligation at end of year	9.5	9.7
Accrued pension benefits, current portion	0.6	0.5
Accrued benefits obligation, long-term	8.9	9.2
Net amount recognized	9.5	9.7
Defined Benefit Pension Plan [Member]
Benefit obligation at beginning of year	266.5	246.2
Service cost	5.2	5.1
Interest cost	13.2	13.2
Actuarial loss	19.4	11.0
Benefits paid	(8.2)	(8.1)
Benefit obligation at end of year	295.9	266.5
Accrued pension benefits, current portion	0.1	1.0
Accrued benefits obligation, long-term	78.5	49.8
Net amount recognized	$ (78.6)	$ (50.8)