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Stock-Based Compensation (Schedule of Assumptions Used to Estimate Weighted-Average Fair Value of Options Granted) (Details)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]      
Dividend yield 3.90% 3.20% 3.10%
Volatility 20.80% 15.60% 16.00%
Risk-free interest rate 2.80% 1.80% 1.20%
Expected life - years 4 years 7 months 6 days 4 years 7 months 6 days 4 years 7 months 6 days