Retirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Pension Benefits [Member]
Components of net periodic benefit cost
Service cost	$ 19.7	$ 22.9	$ 59.0	$ 69.0
Interest cost	43.6	40.0	130.8	120.2
Expected return on plan assets	(54.5)	(56.5)	(163.5)	(169.7)
Amortization:
Prior service credit	(0.7)	(0.6)	(2.1)	(1.9)
Net actuarial loss	25.0	36.1	74.8	108.5
Net periodic benefit cost	33.1	41.9	99.0	126.1
Other Postretirement Benefits [Member]
Components of net periodic benefit cost
Service cost	0.5	0.6	1.5	1.8
Interest cost	1.7	1.6	4.9	4.7
Amortization:
Prior service credit	(2.6)	(2.7)	(7.8)	(8.1)
Net actuarial loss	0.8	1.1	2.4	3.3
Net periodic benefit cost	$ 0.4	$ 0.6	$ 1.0	$ 1.7