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Stock Plans (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2012
Deferred Compensation Plan |  |  |
Compensation expense related to employer contributions under defined contribution plans, including the DCP | $ 14.4 | $ 14.6 | $ 15.9
Employee Stock Option |  |  |
Stock Incentive Plans |  |  |
Securities available for future issuance (in shares) | 19,800,000 |  |
Expiration term of unexercised options | 7 years |  |
Number of Options |  |  |
Balance at the beginning of the period (in shares) | 1,600,000 | 2,500,000 |
Granted (in shares) | 600,000 |  |
Exercised (in shares) | (500,000) | (800,000) | (400,000)
Cancelled (in shares) | (100,000) | (100,000) |
Balance at the end of the period (in shares) | 1,600,000 | 1,600,000 | 2,500,000
Exercisable at the end of the period (in shares) | 900,000 | 1,400,000 | 2,100,000
Stock options, Weighted Average Exercise Price |  |  |
Balance at the beginning of the period (in dollars per share) | $ 24.73 | $ 22.81 |
Granted (in dollars per share) | 31.62 |  |
Exercised (in dollars per share) | 23.64 | 18.31 | $ 11.40
Cancelled (in dollars per share) | 26.87 | 26.83 | 26.23
Balance at the end of the period (in dollars per share) | 27.69 | 24.73 | 22.81
Exercisable at the end of the period (in dollars per share) | $ 25.16 | $ 24.51 | $ 22.07
Performance Earnings Program |  |  |
Compensation expense |  |  |
Unrecognized compensation expense | $ 62.4 |  |
Vesting period | 3 years |  |
Restricted Stock Units (RSUs) |  |  |
Compensation expense |  |  |
Recognized compensation expense | $ 34.4 | $ 32.6 | $ 26.6
Restricted and Performance Stock Award [Member] |  |  |
Stock Incentive Plans |  |  |
Securities available for future issuance (in shares) | 9,900,000 |  |

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