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Share-Based Compensation - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common stock, authorized shares 6,000,000,000 6,000,000,000  
2017 Employee Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares of common stock reserved for future issuance 5,495,914    
Compensation expense $ 16,000,000 $ 16,000,000 $ 15,000,000
Unrecognized compensation costs related to unvested awards $ 16,000,000    
Unrecognized compensation costs related to unvested awards, weighted-average period 1 year 2 months 12 days    
Total fair value of shares vested $ 21,000,000 $ 9,000,000 $ 9,000,000
2017 Employee Plan [Member] | Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common stock, authorized shares 8,000,000    
2017 Director Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares of common stock reserved for future issuance 293,269    
2017 Director Plan [Member] | Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common stock, authorized shares 450,000    
Performance Stock Units ("PSUs") [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Share-based compensation arrangement by share-based payment award performance period 3 years    
Market capitalization $ 1,000,000,000    
Vesting rights zero to 200    
Performance Stock Units ("PSUs") [Member] | Maximum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Vesting rights 200%    
Performance Stock Units ("PSUs") [Member] | Minimum [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Vesting rights 0%