Stock-Based Compensation (Tables)

12 Months Ended

Apr. 30, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Compensation, Stock Appreciation Rights Award Activity [Table Text Block]

The following table presents information about SSARs outstanding as of April 30, 2019, and for the year then ended.

	Number of SSARs (in thousands)		Weighted- Average Exercise Price per SSAR		Weighted- Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding at April 30, 2018	7,215		$	29.67
Granted	605		54.00
Exercised	(903	)	17.13
Forfeited or expired	(65	)	52.49
Outstanding at April 30, 2019	6,852		$	33.25	4.9	$	138
Exercisable at April 30, 2019	4,381		$	28.10	3.6	$	110

Schedule of Share-Based Payment Award, Stock Appreciation Rights, Valuation Assumptions [Table Text Block]

The weighted-average grant-date fair values and related valuation assumptions for the SSARS granted during each of the last three years were as follows:

	2017			2018			2019
Grant-date fair value	$	5.73		$	6.79		$	11.06
Valuation assumptions:
Expected term (years)	7.00			7.00			7.00
Risk-free interest rate	1.4		%	2.2		%	2.9		%
Expected volatility	16.3		%	15.6		%	17.1		%
Expected dividend yield	1.6		%	1.5		%	1.4		%

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

The following table presents information about RSUs outstanding as of April 30, 2019, and for the year then ended.

	Number of RSUs (in thousands)		Weighted- Average Fair Value at Grant Date
Outstanding at April 30, 2018	418		$	42.90
Granted	98		$	55.29
Converted to common shares	(123	)	$	45.44
Forfeited	(11	)	$	55.15
Outstanding at April 30, 2019	382		$	44.91

Schedule of Share-Based Payment Award, Restricted Stock Units, Valuation Assumptions [Table Text Block]

The weighted average grant-date fair values and related valuation assumptions for these awards granted during each of the last three years were as follows:

	2017			2018			2019
Grant-date fair value	$	38.07		$	46.93		$	55.29
Valuation assumptions:
Risk-free interest rate	0.8		%	1.5		%	2.7		%
Expected volatility	17.8		%	18.9		%	20.8		%
Expected dividend yield	1.3		%	1.4		%	1.2		%
Remaining performance period (years) as of grant date	2.8			2.8			2.8

Grant Date Fair Values of DSUs [Table Text Block]

The weighted average grant-date fair values for these awards granted during each of the last three years were as follows:

	2017		2018		2019
Grant-date fair value	$	42.06	$	41.81	$	54.20

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

The pre-tax stock-based compensation expense and related deferred income tax benefits recognized during the last three fiscal years were as follows:

	2017		2018		2019
Pre-tax compensation expense	$	14	$	19	$	14
Deferred tax benefit	5		6		2

Stock-Based Awards, Other Information [Table Text Block]

Further information related to our stock-based awards for the last three years is as follows:

	2017		2018		2019
Intrinsic value of SSARs exercised	$	28	$	73	$	31
Fair value of shares vested1	8		6		20
Excess tax benefit from exercise / vesting of awards	9		18		7