v3.20.1
Leases​ (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Leases [Abstract]      
Lease cost $ 15 $ 16  
Right-of-use asset obtained in exchange for operating lease liability $ 9    
Weighted-average remaining lease term 6 years 3 months 18 days   6 years 8 months 12 days
Weighted-average discount rate 5.90%   6.00%
Operating Lease Obligation      
2020 $ 30   $ 38
2021 32   29
2022 25   22
2023 18   17
2024 14   14
Thereafter 37   38
Total lease payments 156   158
Less: imputed interest 28   29
Present value of lease liabilities $ 128   $ 129