Retirement Benefits (Details 5) - USD ($) $ in Millions | Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2014 |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | $ 3,447.9 | $ 3,262.5 | |
Fair Value, Inputs, Level 1 [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 1,225.5 | 1,062.3 | |
Fair Value, Inputs, Level 2 [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 2,015.2 | 2,002.8 | |
Fair Value, Inputs, Level 3 [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 207.2 | 197.4 | $ 199.3 |
Cash and Cash Equivalents [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 2.9 | 5.1 | |
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 | 1.9 | 2.3 | |
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 | 2.9 | 5.1 | |
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 | 1.9 | 2.3 | |
Common stock [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 705.9 | 628.5 | |
Common stock [Member] | Non-U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 48.6 | 37 | |
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 | 705.9 | 628.5 | |
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 | 48.6 | 37 | |
Mutual funds [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 203.6 | 174.6 | |
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 | 203.6 | 174.6 | |
Equity Common collective trusts [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 483.6 | 467.5 | |
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 | 279.3 | 259.5 | |
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 | 483.6 | 467.5 | |
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 | 279.3 | 259.5 | |
Corporate debt [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 591.8 | 643.8 | |
Corporate debt [Member] | Non-U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 34.1 | 40 | |
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 | 591.8 | 643.8 | |
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 | 34.1 | 40 | |
U.S. Government Securities [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 352.1 | 333.3 | |
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 | 252.6 | 212 | |
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 | 99.5 | 121.3 | |
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 | 17.6 | 9.4 | |
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 | 10 | 2.8 | |
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 | 7.6 | 6.6 | |
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 | 161.4 | 124.8 | |
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 | 271.1 | 258.6 | |
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 | 161.4 | 124.8 | |
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 | 271.1 | 258.6 | |
Private equity [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 57.1 | 70.2 | |
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 | 57.1 | 70.2 | 78.8 |
Alternative equity [Member] | U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 56.9 | 50.7 | |
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 | 56.9 | 50.7 | 49.9 |
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 | 79.7 | 63.8 | |
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 | 0.9 |
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 | 79.7 | 63.8 | 57.8 |
Real estate [Member] | Non-U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 94.6 | 88.1 | |
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 | 85.4 | 79.4 | |
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 | 9.2 | 8.7 | 8.6 |
Other [Member] | Non-U.S. Pension Benefit Plans [Member] | | | |
Investments measured at fair value | | | |
Defined benefit plan fair value of plan assets | 4.8 | 4.4 | |
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 | 1.4 | 1.3 | |
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 | $ 3.4 | $ 3.1 | $ 3.3 |