Retirement Benefits (Details 5) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Investments measured at fair value
Defined benefit plan fair value of plan assets	$ 3,262.5	$ 3,591.0
Fair Value, Inputs, Level 1 [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	1,062.3	1,213.8
Fair Value, Inputs, Level 2 [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	2,002.8	2,177.9
Fair Value, Inputs, Level 3 [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	197.4	199.3	$ 181.3
Cash and Cash Equivalents [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	5.1	1.9
Cash and Cash Equivalents [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	2.3	7.2
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	5.1	1.9
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	2.3	7.2
Common stock [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	628.5	706.8
Common stock [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	37.0	46.4
Common stock [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	628.5	706.8
Common stock [Member] | Fair Value, Inputs, Level 1 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	37.0	46.4
Mutual funds [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	174.6	216.8
Mutual funds [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	174.6	216.8
Equity Common collective trusts [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	467.5	527.2
Equity Common collective trusts [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	259.5	286.0
Equity Common collective trusts [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	467.5	527.2
Equity Common collective trusts [Member] | Fair Value, Inputs, Level 2 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	259.5	286.0
Corporate debt [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	643.8	692.6
Corporate debt [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	40.0	31.0
Corporate debt [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	643.8	692.6
Corporate debt [Member] | Fair Value, Inputs, Level 2 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	40.0	31.0
U.S. Government Securities [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	333.3	378.6
U.S. Government Securities [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	212.0	231.4
U.S. Government Securities [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	121.3	147.2
Non-U.S. Government securities [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	9.4	18.2
Non-U.S. Government securities [Member] | Fair Value, Inputs, Level 1 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	2.8	3.3
Non-U.S. Government securities [Member] | Fair Value, Inputs, Level 2 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	6.6	14.9
Fixed income securities Common collective trusts [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	124.8	129.4
Fixed income securities Common collective trusts [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	258.6	266.7
Fixed income securities Common collective trusts [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	124.8	129.4
Fixed income securities Common collective trusts [Member] | Fair Value, Inputs, Level 2 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	258.6	266.7
Private equity [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	70.2	78.8
Private equity [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	70.2	78.8	80.4
Alternative equity [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	50.7	49.9
Alternative equity [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	50.7	49.9	42.1
Insurance contracts [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	0.9	0.9
Insurance contracts [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	63.8	57.8
Insurance contracts [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	0.9	0.9	0.8
Insurance contracts [Member] | Fair Value, Inputs, Level 3 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	63.8	57.8	45.5
Real estate [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	88.1	88.9
Real estate [Member] | Fair Value, Inputs, Level 2 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	79.4	80.3
Real estate [Member] | Fair Value, Inputs, Level 3 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	8.7	8.6	8.3
Other [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	4.4	5.9
Other [Member] | Fair Value, Inputs, Level 2 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	1.3	2.6
Other [Member] | Fair Value, Inputs, Level 3 [Member] | Non-U.S. Pension Benefit Plans [Member]
Investments measured at fair value
Defined benefit plan fair value of plan assets	$ 3.1	$ 3.3	$ 4.2