Retirement Benefits (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Settlements	$ 5.5	$ 1.0	$ 9.6	$ 3.0
Defined Benefit Pension Plan [Member] | U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	7.0	9.1	22.2	27.4
Interest cost	27.5	27.7	80.0	83.1
Expected return on plan assets	(51.6)	(50.5)	(156.0)	(151.5)
Prior service cost amortization	0.6	0.7	1.8	2.2
Actuarial loss amortization	20.9	21.3	67.9	63.9
Settlements	5.5	1.0	9.6	3.6
Curtailment			4.3	0.0
Special termination benefits	0.8	1.4	1.8	2.0
Other	0.0	0.0	0.0	0.0
Net periodic benefit cost	10.7	10.7	31.6	30.7
Defined Benefit Pension Plan [Member] | U.S. [Member] | Discontinued Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	0.0	1.9	0.7	5.8
Defined Benefit Pension Plan [Member] | U.S. [Member] | Continuing Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	10.7	8.8	30.9	24.9
Defined Benefit Pension Plan [Member] | International [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	6.5	6.1	19.5	18.4
Interest cost	8.2	11.2	23.7	33.9
Expected return on plan assets	(18.9)	(19.8)	(55.7)	(60.1)
Prior service cost amortization	0.0	0.0	(0.1)	(0.1)
Actuarial loss amortization	13.5	8.9	40.6	27.2
Settlements	0.0	0.0	1.7	0.0
Curtailment			(1.3)	0.0
Special termination benefits	0.0	0.0	0.5	0.0
Other	0.2	0.6	0.7	1.6
Net periodic benefit cost	9.5	7.0	29.6	20.9
Defined Benefit Pension Plan [Member] | International [Member] | Discontinued Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	0.0	0.2	4.1	1.8
Defined Benefit Pension Plan [Member] | International [Member] | Continuing Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	9.5	6.8	25.5	19.1
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.2	0.5	0.9	1.6
Interest cost	0.4	0.5	1.2	1.5
Expected return on plan assets	0.0	0.0	0.0	0.0
Prior service cost amortization	0.0	0.0	0.0	0.0
Actuarial loss amortization	0.0	0.2	0.2	0.5
Settlements	0.0	0.0	0.0	0.0
Curtailment			0.0	0.0
Special termination benefits	0.0	0.0	0.0	0.0
Other	0.0	0.0	0.0	0.0
Net periodic benefit cost	0.6	1.2	2.3	3.6
Other Postretirement Benefits Plan [Member] | Discontinued Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	0.0	0.1	0.0	0.1
Other Postretirement Benefits Plan [Member] | Continuing Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 0.6	$ 1.1	$ 2.3	$ 3.5