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Stock-Based Compensation (Weighted Average Grant Date Fair Value Assumptions) (Details) - Employee Stock Option - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Grant date fair value $ 8.98 $ 8.48
Grant date strike price $ 44.38 $ 48.71
Expected volatility 29.97% 26.01%
Expected life 6 years 3 months 4 years 3 months
Risk-free interest rate 2.59% 2.73%