Share-based compensation plans (Tables)

9 Months Ended

Sep. 30, 2022

Share-based Payment Arrangement [Abstract]

Compensation expense by plan

Compensation expenses are classified as selling, general and administrative expenses in the condensed consolidated statements of operations. Compensation expenses for the share-based awards were as follows:

	Compensation Expense			Compensation Expense
	Three Months Ended September 30,			Nine Months Ended September 30,
(in millions)	2022		2021	2022		2021
Performance share units	$	10.5	6.2	$	26.3	18.7
Restricted stock units	3.3		2.4	8.7		7.0
Deferred stock units and fees paid in stock	0.3		0.4	1.0		1.0
Performance-based stock options	—		—	—		0.3
Time-based vesting stock options	0.1		0.2	0.3		0.9
Cash based awards	0.1		0.2	1.2		0.8
Share-based payment expense	14.3		9.4	37.5		28.7
Income tax benefit	(3.4)		(2.1)	(8.7)		(6.5)
Share-based payment expense, net of tax	$	10.9	7.3	$	28.8	22.2

Option activity

The following table summarizes performance-based stock option activity during the first nine months of 2022:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Outstanding balance as of December 31, 2021	946.5	$	10.25
Expired(a)	(15.3)	17.92
Exercised	(485.0)	5.91
Outstanding balance as of September 30, 2022	446.2	$	14.70

(a)Although the service condition had been met, these 2018 performance options expired in accordance with the terms of the underlying award agreement.

The following table summarizes time-based stock option activity during the first nine months of 2022: 

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Outstanding balance as of December 31, 2021	177.1	$	21.42
Expired	(15.5)	21.51
Outstanding balance as of September 30, 2022	161.6	$	21.41

Nonvested share activity

The following table summarizes RSU activity during the first nine months of 2022: 

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2021	251.1	$	74.37
Granted	238.6	64.60
Forfeited	(34.3)	70.52
Vested	(78.4)	77.12
Nonvested balance as of September 30, 2022	377.0	$	67.97

The following table summarizes all PSU activity during the first nine months of 2022:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2021	661.0	$	81.75
Granted	288.0	67.13
Forfeited or expired(a)	(74.7)	82.82
Vested(b)	(142.9)	77.61
Nonvested balance as of September 30, 2022	731.4	$	76.70

(a)Although the service condition had been met, 23.6 thousand TSR PSUs granted in 2019 expired in accordance with the market condition terms of the underlying award agreement. These units had a weighted average grant-date fair value of $105.57 per share.

(b)The vested PSUs presented are based on the target amount of the award. In accordance with the terms of the underlying award agreements, the actual shares earned and distributed for the performance period ended December 31, 2021 were 144.4 thousand, compared to target shares of 142.9 thousand.

The following table summarizes all DSU activity during the first nine months of 2022:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2021	14.3	$	78.74
Granted	18.6	54.67
Vested	(13.0)	79.79
Nonvested balance as of September 30, 2022	19.9	$	55.59