Share-based compensation plans (Tables)

9 Months Ended

Sep. 30, 2024

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)	2024		2023	2024		2023
Performance stock units	$	4.7	3.7	$	15.5	16.6
Restricted stock units	2.5		2.4	7.6		8.0
Deferred stock units and fees paid in stock	0.3		0.3	1.0		1.0
Cash based awards	0.9		0.1	2.3		1.6
Share-based payment expense	8.4		6.5	26.4		27.2
Income tax benefit	(1.9)		(1.5)	(6.0)		(6.3)
Share-based payment expense, net of tax	$	6.5	5.0	$	20.4	20.9

Option activity

The following table summarizes performance-based stock option activity during the first nine months of 2024:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Outstanding balance as of December 31, 2023	174.4	$	17.92
Exercised	(174.4)	17.92
Outstanding balance as of September 30, 2024	—	$	—

The following table summarizes time-based stock option activity during the first nine months of 2024: 

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Outstanding balance as of December 31, 2023	115.7	$	21.43
Exercised	(93.2)	21.54
Outstanding balance as of September 30, 2024	22.5	$	20.98

Nonvested share activity

The following table summarizes RSU activity during the first nine months of 2024: 

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2023	320.2	$	65.89
Granted	137.8	83.73
Forfeited	(20.9)	71.76
Vested	(145.1)	67.48
Nonvested balance as of September 30, 2024	292.0	$	73.10

The following table summarizes all PSU activity during the first nine months of 2024:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2023	698.5	$	72.15
Granted	214.0	82.19
Forfeited or expired	(30.3)	69.79
Vested(a)	(229.1)	80.47
Nonvested balance as of September 30, 2024	653.1	$	72.63

(a)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, 2023 were 438.7 thousand, compared to target shares of 229.1 thousand.

The following table summarizes all DSU activity during the first nine months of 2024:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2023	19.2	$	62.43
Granted	13.6	87.93
Vested	(19.2)	62.43
Nonvested balance as of September 30, 2024	13.6	$	87.93