XML 172 R150.htm IDEA: XBRL DOCUMENT v3.20.4
Stock-Based Compensation Weighted Average Assumptions - Stock Options (Details)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
EIP [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield   1.55% 2.10%
Expected Volatility   19.80% 23.30%
Risk Free Interest Rate   2.40% 2.80%
Expected life of stock options granted during period   6 years 1 month 6 days 6 years 2 months 12 days
OIP [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield 1.67%    
Expected Volatility 23.14%    
Risk Free Interest Rate 1.30%    
Expected life of stock options granted during period 6 years