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Restructuring Charges (Additional Information) (Details) - USD ($)
$ in Millions
1 Months Ended 3 Months Ended 9 Months Ended
Jul. 31, 2019
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]          
Term of contract 10 years        
Workforce Reduction          
Restructuring Cost and Reserve [Line Items]          
Office consolidation $ 3 $ 0 $ 3 $ 0 $ 5