Retirement Benefits (Schedule of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended																12 Months Ended
	Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Settlement loss	$ 5.5	[1]	$ 0	[1]	$ 0	[1]	$ 0	[1]	$ 7.9	[1]	$ 4.5	[1]	$ 0	[1]	$ 0	[1]	$ 5.5	[1]	$ 12.4	[1]	$ 0	[1]
US [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost																	42.6		51.8		45.1
Interest cost																	130.7		117.1		124.2
Expected return on plan assets																	(187.8)		(185.4)		(178.2)
Actuarial loss amortization																	78.3		116.0		78.6
Prior service cost amortization																	2.9		2.9		2.7
Settlement loss																	4.8		11.5		0
Special termination benefits																	0.2		1.2		4.6
Other																	0		0		0
Net periodic benefit cost																	71.7		115.1		77.0
International [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost																	36.0		31.5		24.1
Interest cost																	67.2		57.3		62.3
Expected return on plan assets																	(78.1)		(71.2)		(66.7)
Actuarial loss amortization																	36.1		27.0		17.4
Prior service cost amortization																	0.2		0.2		0.5
Settlement loss																	0.7		0.9		1.4
Special termination benefits																	0.1		6.2		2.2
Other																	2.0		2.7		2.2
Net periodic benefit cost																	64.2		54.6		43.4
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost																	3.3		4.3		4.5
Interest cost																	2.3		1.9		3.9
Actuarial loss amortization																	1.7		2.3		2.9
Net periodic benefit cost																	$ 7.3		$ 8.5		$ 11.3

[1] For additional information, see Note 15, Retirement Benefits.