v3.20.2
Leases​ (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Leases [Abstract]          
Lease cost $ 14 $ 16 $ 29 $ 32  
Right-of-use asset obtained in exchange for operating lease liability $ 23   $ 32    
Weighted-average remaining lease term 6 years 10 months 24 days   6 years 10 months 24 days   6 years 8 months 12 days
Weighted-average discount rate 6.00%   6.00%   6.00%
Operating Lease Obligation          
2020 $ 21   $ 21   $ 38
2021 35   35   29
2022 28   28   22
2023 22   22   17
2024 17   17   14
Thereafter 52   52   38
Total lease payments 175   175   158
Less: imputed interest 33   33   29
Present value of lease liabilities $ 142   $ 142   $ 129