v3.19.3.a.u2
Non-Mineral Leases - Operating Lease Rentals (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Operating lease rental expense    
Operating Leases, Rent Expense, Minimum Rentals $ 253 $ 264
Less sublease rentals (16) (20)
Operating Leases, Rent Expense, Total $ 237 $ 244