Retirement Benefits (Details 6) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	$ 3,591.0
Plan assets at end of year	3,262.5	$ 3,591.0
Private equity [Member] | U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	78.8
Plan assets at end of year	70.2	78.8
Alternative equity [Member] | U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	49.9
Plan assets at end of year	50.7	49.9
Insurance contracts [Member] | U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	0.9
Plan assets at end of year	0.9	0.9
Insurance contracts [Member] | Non-U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	57.8
Plan assets at end of year	63.8	57.8
Real estate [Member] | Non-U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	88.9
Plan assets at end of year	88.1	88.9
Other [Member] | Non-U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	5.9
Plan assets at end of year	4.4	5.9
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	199.3	181.3
Realized Gains (Losses)	11.2	9.1
Unrealized Gains (Losses)	2.2	13.7
Purchases, Sales, Issuances, and Settlements, Net	(15.3)	(4.8)
Plan assets at end of year	197.4	199.3
Fair Value, Inputs, Level 3 [Member] | Private equity [Member] | U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	78.8	80.4
Realized Gains (Losses)	7.2	7.8
Unrealized Gains (Losses)	(11.0)	(3.5)
Purchases, Sales, Issuances, and Settlements, Net	(4.8)	(5.9)
Plan assets at end of year	70.2	78.8
Fair Value, Inputs, Level 3 [Member] | Alternative equity [Member] | U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	49.9	42.1
Realized Gains (Losses)	4.0	1.3
Unrealized Gains (Losses)	1.7	2.8
Purchases, Sales, Issuances, and Settlements, Net	(4.9)	3.7
Plan assets at end of year	50.7	49.9
Fair Value, Inputs, Level 3 [Member] | Insurance contracts [Member] | U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	0.9	0.8
Purchases, Sales, Issuances, and Settlements, Net	0.0	0.1
Plan assets at end of year	0.9	0.9
Fair Value, Inputs, Level 3 [Member] | Insurance contracts [Member] | Non-U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	57.8	45.5
Unrealized Gains (Losses)	11.3	14.1
Purchases, Sales, Issuances, and Settlements, Net	(5.3)	(1.8)
Plan assets at end of year	63.8	57.8
Fair Value, Inputs, Level 3 [Member] | Real estate [Member] | Non-U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	8.6	8.3
Unrealized Gains (Losses)	0.1	0.3
Plan assets at end of year	8.7	8.6
Fair Value, Inputs, Level 3 [Member] | Other [Member] | Non-U.S. Pension Benefit Plans [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at beginning of year	3.3	4.2
Unrealized Gains (Losses)	0.1	0.0
Purchases, Sales, Issuances, and Settlements, Net	(0.3)	(0.9)
Plan assets at end of year	$ 3.1	$ 3.3