XML 92 R66.htm IDEA: XBRL DOCUMENT v3.20.4
Incentive Stock Program - Options Fair Value (Details) - Stock options - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Incentive Stock Program      
Fair value of an option granted (in dollars per share) $ 14.39 $ 14.50 $ 10.93
Fair value assumptions:      
Risk-free interest rate (as a percent) 1.30% 2.50% 2.70%
Average life of options (years) 6 years 6 years 6 years
Volatility (as a percent) 19.40% 19.80% 19.00%
Dividend yield (as a percent) 1.60% 1.70% 1.90%