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Share-Based Compensation - Performance shares and units additional information (Details) - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility 18.10% 21.30% 21.30%
Vesting period 3 years    
Risk free interest rate 2.50% 2.80% 2.00%
Performance Common Shares and Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility 17.10% 16.20% 0.00%
Vesting period 3 years    
Performance shares and units granted 696,360 743,513 0
Weighted average grant date fair value $ 36.05 $ 24.77 $ 0
Risk free interest rate 2.50% 2.60% 0.00%