Stock Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Summary of Significant Stock Options Granted

The fair value of stock option awards granted in 2019 and 2018 was estimated at the date of grant using a Black-Scholes option-pricing method with the following assumptions:

	2019			2018
Weighted-average fair value per option	$	9.58		$	10.29
Risk-free interest rate	2.46		%	2.62		%
Dividend yield	2.52		%	2.30		%
Expected stock volatility	28.29		%	27.78		%
Expected life - years	5			5

Summary of Stock Option Activity

A summary of stock option award activity for the year ended December 31, 2020 is presented below:

	Number of Shares	Weighted-average Exercise Price		Weighted-average Remaining Contractual Term	Aggregate Intrinsic Value (millions)
Outstanding - beginning of year	2,913,272	$	40.10
Exercised	(956,258)	39.07
Canceled of expired	(52,265)	43.27
Outstanding - end of year	1,904,749	$	40.53	7 years	$	70.1
Options expected to vest	1,904,749	40.53		7 years	70.1
Options exercisable	1,259,075	38.94		6 years	48.4

Share-Based Compensation Arrangements by Share-based Payment Award

A summary of those awards granted in 2020 is presented below:

	Expected to be Settled in Equity	Expected to be Settled in Cash	Total Awards Granted
Performance-based restricted stock units	442,371	11,251	453,622
Time-based restricted stock units	204,550	4,480	209,030
Deferred shares	5,000	—	5,000

Summary of Restricted Share Activity

A summary of stock award activity, including performance-based restricted stock units, time-based restricted stock units and deferred shares that will settle in common shares for the year ended December 31, 2020 is as follows:

	Number of Shares	Weighted-average Grant Date Fair Value
Outstanding - beginning of year	1,106,386	$	43.13
Granted - new awards	651,921	50.05
Vested	(557,590)	43.76
Canceled or expired	(75,245)	47.97
Outstanding - end of year	1,125,472	$	46.50