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Fair value of deferred stock units paid

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Share-Based Payments, Conversion Ratio For Separation Adjustment

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Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement.

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The aggregate cash inflow comprised of the amount received from (a) employees to acquire the entity's shares under incentive awards, including stock option exercises and restricted stock arrangements, and (b) the excess tax benefit arising from such transactions.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Price of a single share of a number of saleable stocks of a company.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Share-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) $ / shares	Oct. 03, 2016 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grant \| shares	4,922,382
Closing stock price (in dollars per share) \| $ / shares	$ 151.22	$ 150.35		$ 140.38
Conversion ratio for separation adjustments	1.071
Cash received from option exercises	$ 68.4	$ 141.3	$ 121.3
Deferred Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units/shares granted \| shares	283,000
Weighted-average grant date fair value (in dollars per share) \| $ / shares	$ 148.89
Cash payments made for deferred stock units	$ 2.1	2.9	9.6
Unrecognized compensation costs	$ 39.0
Unrecognized compensation costs, period for recognition, years	2 years
Fair value of deferred stock units paid	$ 36.6	$ 41.6	$ 35.5
Deferred Stock Units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting or deferral Period	2 years
Deferred Stock Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting or deferral Period	5 years
Director Deferred Stock Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period after service in which to elect payment	10 years
Market-Based Deferred Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting or deferral Period	3 years
Number of units/shares granted \| shares	117,692	130,167
Weighted-average grant date fair value (in dollars per share) \| $ / shares	$ 156.87	$ 135.49
Time-Based Deferred Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units/shares granted \| shares	165,120.792160577
Weighted-average grant date fair value (in dollars per share) \| $ / shares	$ 143.75
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting or deferral Period	3 years
Unrecognized compensation costs	$ 0.1
Unrecognized compensation costs, period for recognition, years	2 months
Exercisable period from grant date	10 years
Weighted-average grant date fair value of stock option (in dollars per share) \| $ / shares			$ 37.19
Intrinsic value of stock options exercised	$ 57.3	$ 115.3	$ 115.5
Cash received from option exercises	68.4
Tax benefit realized from stock option exericses	19.9
Excess tax benefit	13.9
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs	$ 0.4
Unrecognized compensation costs, period for recognition, years	1 year 5 months
Fair value of vested restricted stock	$ 4.1	$ 4.3	$ 1.4
Restricted Stock \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting or deferral Period	1 year
Restricted Stock \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting or deferral Period	4 years