Share-based compensation plans (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs 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)	2020		2019	2020		2019
Performance share units	$	5.5	7.0	$	12.5	21.6
Restricted stock units	1.5		1.4	4.5		5.3
Deferred stock units and fees paid in stock	0.3		0.3	0.9		0.9
Performance-based stock options	0.5		0.8	1.7		7.3
Time-based vesting stock options	0.5		0.3	1.3		0.8
Cash based awards	0.4		—	0.8		—
Share-based payment expense	8.7		9.8	21.7		35.9
Income tax benefit	(1.9)		(2.3)	(4.7)		(8.3)
Share-based payment expense, net of tax	$	6.8	7.5	$	17.0	27.6

Option activity

The following table summarizes performance-based stock option activity during the first nine months of 2020: 

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Outstanding balance as of December 31, 2019	1,191.1	$	11.52
Granted	—	—
Forfeited	—	—
Exercised	—	—
Outstanding balance as of September 30, 2020	1,191.1	$	11.52

The following table summarizes time-based stock option activity during the first nine months of 2020: 

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Outstanding balance as of December 31, 2019	127.0	$	21.56
Granted	80.8	21.10
Forfeited	—	—
Exercised	—	—
Outstanding balance as of September 30, 2020	207.8	$	21.38

Nonvested share activity

The following table summarizes RSU activity during the first nine months of 2020: 

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2019	172.7	$	71.87
Granted	93.2	71.78
Forfeited	(11.3)	78.81
Conversion to cash settled awards(a)	(1.3)	72.80
Vested	(84.9)	67.41
Nonvested balance as of September 30, 2020	168.4	$	73.60

(a)Certain RSUs were modified in the first quarter of 2020 to change the awards' classification from share-settled to cash-settled. The weighted-average grant date fair value per share shown above is the removal of the original fair value.

The following table summarizes all PSU activity during the first nine months of 2020:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2019	564.2	$	70.10
Granted	248.4	83.68
Forfeited	(22.0)	76.23
Conversion to cash settled awards(a)	(4.6)	65.42
Vested(b)	(204.3)	56.72
Nonvested balance as of September 30, 2020	581.7	$	80.40

(a)Certain IM PSUs were modified in the first quarter of 2020 to change the awards' classification from share-settled to cash-settled. The weighted-average grant date fair value per share shown above is the removal of the original fair value.

(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, 2019 were 394.0 thousand, compared to target shares of 204.3 thousand.

The following table summarizes all DSU activity during the first nine months of 2020:

	Shares (in thousands)	Weighted-Average Grant-Date Fair Value
Nonvested balance as of December 31, 2019	12.1	$	79.69
Granted	21.6	40.46
Vested	(12.1)	79.69
Nonvested balance as of September 30, 2020	21.6	$	40.46