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Revenue Recognition - Additional Information (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Disaggregation of Revenue [Line Items]      
Total contract revenues $ 1,799 $ 2,079  
Customer Advance Deposits      
Disaggregation of Revenue [Line Items]      
Revenue recognized 15 15 $ 59
Occupancy      
Disaggregation of Revenue [Line Items]      
Total contract revenues $ 317 $ 386