Share-Based Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Summary of restricted stock activity

The following is a summary of restricted stock unit activity for the three months ended March 31, 2021. The fair value of the restricted share unit awards is determined using the closing price of our common stock on date of grant:

	Share units (in thousands)	Weighted Average Grant Date Fair Value /Share
Outstanding at January 1, 2021	537	$	74.62
Granted	191	102.23
Vested	(197)	76.56
Forfeited	(2)	80.74
Outstanding at March 31, 2021	529	$	83.77

Summary of performance based share grants

The following is a summary of Return on Invested Capital ("ROIC") performance share unit grants for the three months ended March 31, 2021. The fair value of the ROIC performance share units is equal to the closing share price on the date of the grant:

	Share units  (in thousands)	Weighted Average Grant Date Fair Value /Share
Outstanding at January 1, 2021	182	$	76.12
Granted	60	102.23
Forfeited	(58)	75.10
Outstanding at March 31, 2021	184	$	84.55

TSR Performance Share Unit Grants

The following is a summary of our Total Shareholder Return ("TSR") performance share unit grants for the three months ended March 31, 2021:

	Share units (in thousands)	Weighted Average Grant Date Fair Value /Share
Outstanding at January 1, 2021	182	$	96.98
Granted	60	117.56
Adjustment for Market Condition Achieved (a)	35	98.79
Vested	(93)	98.79
Outstanding at March 31, 2021	184	$	102.82

Summary of the changes in outstanding stock options

The following is a summary of the changes in outstanding stock options for the three months ended March 31, 2021:

	Share units (in thousands)	Weighted Average Exercise Price / Share		Weighted  Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in millions)
Outstanding at January 1, 2021	1,961	$	56.66	6.4
Granted	257	102.23
Exercised	(51)	57.01
Forfeited and expired	(1)	24.60
Outstanding at March 31, 2021	2,166	$	62.04	6.6	$	92
Options exercisable at March 31, 2021	1,440	$	51.46	5.3	$	77
Vested and expected to vest as of March 31, 2021	2,073	$	60.95	6.5	$	91

Stock option valuation assumptions

The following are weighted-average assumptions for 2021 grants:

Volatility	26.30		%
Risk-free interest rate	0.86		%
Dividend yield	1.10		%
Expected term (in years)	5.7
Weighted-average fair value / share	$	23.20

Performance-based shares valuation assumptions

The fair value of TSR performance share units was calculated on the date of grant using a Monte Carlo simulation model utilizing several key assumptions, including expected Company and peer company share price volatility, correlation coefficients between peers, the risk-free rate of return, the expected dividend yield and other award design features. The following are weighted-average assumptions for 2021 grants:

Volatility	33.5	%
Risk-free interest rate	0.24	%