Share Plans (Tables)

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

Share-based Compensation Expense

Total share-based compensation expense for the three and six months ended June 30, 2021 and 2020 was as follows:

	Three months ended				Six months ended
In millions	June 30, 2021		June 30, 2020		June 30, 2021		June 30, 2020
Restricted stock units	$	3.6	$	3.1	$	7.0	$	6.3
Stock options	0.9		0.6		1.8		1.6
Performance share units	6.5		0.5		7.8		2.5
Total share-based compensation expense	$	11.0	$	4.2	$	16.6	$	10.4

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

We estimated the fair value of each stock option award issued in the annual share-based compensation grant using a Black-Scholes option pricing model, modified for dividends and using the following assumptions:

	2021 Annual Grant
Risk-free interest rate	0.37	%
Expected dividend yield	1.56	%
Expected share price volatility	29.60	%
Expected term (years)	6.5