Stock-Based Compensation Plans (Tables)

12 Months Ended

May 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Weighted-Average Assumptions

	Year ended May 31,
		2018			2018			2017			2016
	Performance stock options			Stock options
Risk-free interest rate		2.4	%			2.1	%		1.2	%		1.9	%
Dividend yield		3.3	%			3.4	%		3.6	%		3.6	%
Volatility factor		0.18				0.17			0.18			0.18
Expected option life in years		6.5				6.1			6.1			6.1
Weighted-average grant-date   fair value of stock options granted (per share)	$	7.45			$	6.47		$	5.74		$	5.25

Stock Option Activity

				Weighted-
		Weighted-		average
	Shares	average		remaining	Aggregate
	subject	exercise price		contractual	intrinsic
In millions, except per share amounts	to options	per share		term (years)	value(1)
Outstanding as of May 31, 2017	4.2	$	42.02
Granted	0.7	$	57.40
Exercised	(0.4)	$	37.86
Forfeited	(0.1)	$	53.41
Expired	—	$	38.48
Outstanding as of May 31, 2018	4.4	$	44.60	6.1	$	93.0
Exercisable as of May 31, 2018	2.8	$	38.72	4.9	$	76.3

(1) Market price of the underlying stock as of May 31, 2018 less the exercise price.

Other Information Pertaining to Stock Option

	Year ended May 31,
In millions	2018		2017		2016
Total intrinsic value of stock options exercised	$	9.1	$	23.8	$	14.5
Total grant-date fair value of stock options vested	$	4.0	$	4.1	$	4.0

RSU Activity

				Weighted-
		Weighted-		average
		average		remaining
		grant-date		vesting	Aggregate
		fair value		period	intrinsic
In millions, except per share amounts	RSUs	per share		(years)	value(1)
Nonvested as of May 31, 2017	1.6	$	43.53
Granted	0.6	$	51.15
Vested	(1.0)	$	42.12
Forfeited	(0.1)	$	46.27
Nonvested as of May 31, 2018	1.1	$	48.79	3.2	$	69.2

(1) Intrinsic value for RSUs is based on the market price of the underlying stock as of May 31, 2018.

Other Information Pertaining to RSUs

	Year ended May 31,
In millions, except per share amounts	2018		2017		2016
Weighted-average grant-date fair value per share of RSUs granted	$	51.15	$	53.76	$	42.60
Total intrinsic value of RSUs vested	$	60.9	$	32.3	$	25.9
Total grant-date fair value of RSUs vested	$	42.4	$	19.3	$	17.3

Restricted Stock Activity

		Weighted-
		average
		grant-date
	Restricted	fair value
In millions, except per share amounts	shares	per share
Nonvested as of May 31, 2017	0.1	$	53.05
Granted	0.1	$	57.50
Vested	(0.1)	$	50.64
Forfeited	—	$	56.53
Nonvested as of May 31, 2018	0.1	$	56.89

Other Information Pertaining to Restricted Stock

	Year ended May 31,
In millions, except per share amounts	2018		2017		2016
Weighted-average grant-date fair value per share of restricted stock granted	$	57.50	$	60.83	$	47.46
Total grant-date fair value of restricted stock vested	$	3.0	$	3.0	$	3.0

Performance Share Activity

		Weighted-
		average
		grant-date
	Performance	fair value
In millions, except per share amounts	shares	per share
Nonvested as of May 31, 2017	0.4	$	45.66
Granted (1)	0.2	$	53.08
Vested	(0.2)	$	38.68
Forfeited	—	$	48.89
Nonvested as of May 31, 2018	0.4	$	51.53

(1) Performance shares granted assuming achievement of performance goals at target. Actual amount of shares to be earned may differ from this amount.

Other Information Pertaining to Performance Shares

	Year ended May 31,
In millions, except per share amounts	2018		2017		2016
Weighted-average grant-date fair value per share of performance shares granted	$	53.08	$	54.97	$	42.48
Total grant-date fair value of performance shares vested	$	6.6	$	7.8	$	5.9

Performance Stock Options [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock Option Activity

				Weighted-
		Weighted-		average
	Shares	average		remaining	Aggregate
	subject	exercise price		contractual	intrinsic
In millions, except per share amounts	to options	per share		term (years)	value(1)
Outstanding as of May 31, 2017	2.4	$	47.52
Granted(2)	0.1	$	59.93
Exercised	(0.3)	$	30.70
Forfeited	(0.1)	$	60.84
Expired	—	$	—
Outstanding as of May 31, 2018	2.1	$	49.26	6.3	$	34.5
Exercisable as of May 31, 2018	0.8	$	31.99	3.4	$	28.5

(1) Market price of the underlying stock as of May 31, 2018 less the exercise price.

(2) LTIP performance stock options granted assumes achievement of performance goals at target.  Actual amount of shares to be earned may differ from this amount.

Other Information Pertaining to Stock Option

	Year ended May 31,
In millions	2018		2017		2016
Total intrinsic value of stock options exercised	$	7.9	$	12.4	$	1.0
Total grant-date fair value of stock options vested	$	4.9	$	4.9	$	—

Performance-Based Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Restricted Stock Activity

		Weighted-
		average
		grant-date
	Restricted	fair value
In millions, except per share amounts	shares	per share
Nonvested as of May 31, 2017	0.2	$	53.74
Granted(1)	—	$	54.77
Vested	—	$	—
Forfeited	—	$	53.61
Nonvested as of May 31, 2018	0.2	$	53.86

(1) LTIP performance shares granted assumes achievement of performance goals at target.  Actual amount of shares to be earned may differ from this amount.