Retirement Benefits (Details 6) (USD $) In Millions	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Private Equity Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at end of year	$ 85.0	$ 62.2
Private Equity Investments [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at beginning of year	62.2	43.1
Realized Gain	3.2	1.2
Unrealized Gains (Losses)	13.3	6.8
Purchases sales issuances, and settlements, net	6.3	11.1
Plan assets at end of year	85.0	62.2
Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at beginning of year		27.4
Unrealized Gains (Losses)		0.4
Purchases sales issuances, and settlements, net		1.6
Plan assets at end of year	27.8	29.4
Insurance Contracts [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at beginning of year	29.4
Unrealized Gains (Losses)	(4.7)
Purchases sales issuances, and settlements, net	3.1
Plan assets at end of year	27.8
Other [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at beginning of year	11.3
Unrealized Gains (Losses)	0.2
Purchases sales issuances, and settlements, net	(3.5)
Plan assets at end of year	8.0
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at end of year	30.6	34.8
Other [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at beginning of year		12.3
Unrealized Gains (Losses)		0.1
Purchases sales issuances, and settlements, net		(1.1)
Plan assets at end of year	8.0	11.3
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at beginning of year	102.9	82.8
Realized Gain	3.2	1.2
Unrealized Gains (Losses)	8.8	7.3
Purchases sales issuances, and settlements, net	5.9	11.6
Plan assets at end of year	$ 120.8	$ 102.9