Common Stock (Tables)

12 Months Ended

Sep. 30, 2020

Class of Stock Disclosures [Abstract]

Schedule of Stock-Based Compensation Cost

The stock-based compensation cost that was charged against income for all plans was $38.4 million, $34.4 million and $28.1 million for the fiscal years ended September 30, 2020, 2019 and 2018.

We recognize a tax benefit based on the increase in value from the grant date to the exercise date for stock options and from the grant date to the distribution date for the performance share units and restricted share units. The tax benefit is recorded during the year in which the exercise or distribution occurs. The tax benefit for exercises and distributions for the fiscal years ended September 30, 2020, 2019 and 2018 was $4.7 million, $5.2 million, and $16.1 million.

Schedule of Weighted Average Fair Value per Share of Stock Options and Related Valuation Assumptions

The following table sets forth the weighted average fair value per share of stock options and the related valuation assumptions used in the determination of those fair values:

	Year Ended September 30
	2020		2019		2018
Weighted average fair value per share	$	24.80	$	25.28	$	22.50
Valuation assumptions:
Risk-free interest rate	1.6%		3.0%		2.2%
Expected dividend yield	0.8%		0.8%		0.9%
Expected volatility	27.7%		30.5%		30.8%
Weighted average expected life (years)	4.7		4.7		4.9

Schedule of Transactions under Stock Option Plans

The following table summarizes transactions under our stock option plans for the fiscal year ended September 30, 2020:

	Weighted Average Number of Shares (in thousands)	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value (in millions)
Balance Outstanding as of October 1, 2019	718	$	71.14	—	—
Granted	188	103.11		—	—
Exercised	(144)	60.08		—	—
Cancelled/Forfeited	(22)	80.54		—	—
Balance Outstanding as of September 30, 2020	740	$	81.14	6.9	$	7.9
Exercisable as of September 30, 2020	334	$	65.87	5.3	$	6.8
Options Expected to Vest	391	93.56		8.2	1.1

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value, based on our closing stock price of $83.51, as reported by the New York Stock Exchange on September 30, 2020. This amount, which changes continuously based on the fair value of our common stock, would have been received by the option holders had all option holders exercised their options as of the balance sheet date.

Schedule of Transactions for Nonvested RSUs

The following table summarizes transactions for our nonvested RSUs for the fiscal year ended 2020:

	Number of Share Units (in thousands)	Weighted Average Grant Date Fair Value
Nonvested RSUs as of October 1, 2019	371	$	95.76
Granted	242	101.74
Vested	(234)	78.08
Forfeited	(42)	95.14
Nonvested RSUs as of September 30, 2020	337	$	112.41

Schedule of Weighted Average Fair Value per Share of PSUs and Related Valuation Assumptions

The following table sets forth the weighted average fair value per share for PSUs and the related valuation assumptions used in the determination of those fair values. PSUs granted for the fiscal years ended September 30, 2020, 2019 and 2018 are based on company-specific performance targets, with a total shareholder return collar.

	Year Ended September 30
	2020		2019		2018
Weighted average fair value per share	$	110.53	$	112.79	$	87.42
Valuation assumptions:
Risk-free interest rate	1.6%		3.0%		1.9%
Expected volatility	23.8%		22.8%		21.9%

Schedule of Transactions for Nonvested PSUs

The following table summarizes transactions for our nonvested PSUs in fiscal 2020:

	Number of Share Units (in thousands)	Weighted Average Grant Date Fair Value
Nonvested PSUs as of October 1, 2019	206	$	98.78
Granted	161	84.34
Vested	(187)	75.35
Forfeited	(15)	93.47
Nonvested PSUs as of September 30, 2020	165	$	111.73