Share Plans (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Share-based Compensation Expense

Total share-based compensation expense for the three months ended March 31, 2021 and 2020 was as follows:

	Three months ended
In millions	March 31, 2021		March 31, 2020
Restricted stock units	$	3.4	$	3.2
Stock options	0.9		1.0
Performance share units	1.3		2.0
Total share-based compensation expense	$	5.6	$	6.2

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