Retirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Retirement Benefits (Textual) [Abstract]
Voluntary Contribution To Qualified Pension Plan Trust				$ 300
Pension Benefits [Member]
Components of net periodic benefit cost
Service cost	23.0	18.1	46.1	36.0
Interest cost	40.0	42.0	80.2	83.9
Expected return on plan assets	(56.4)	(57.2)	(113.2)	(114.2)
Amortization:
Prior service credit	(0.7)	(0.6)	(1.3)	(1.2)
Net actuarial loss	36.1	23.7	72.4	47.4
Net periodic benefit cost	42.0	26.0	84.2	51.9
Other Postretirement Benefits [Member]
Components of net periodic benefit cost
Service cost	0.6	0.6	1.2	1.1
Interest cost	1.5	1.8	3.1	3.6
Amortization:
Prior service credit	(2.7)	(2.7)	(5.4)	(5.3)
Net actuarial loss	1.1	0.6	2.2	1.2
Net periodic benefit cost	$ 0.5	$ 0.3	$ 1.1	$ 0.6