Leases - Disclosures related to periods prior to adoption of new lease standard minimum lease payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
Minimum lease payments under capital leases
2019	$ 18
2020	16
2021	14
2022	12
2023	12
After 2023	32
Total	104
Less: Amounts representing interest	12
Present value of future minimum lease payments	92
Less: Current obligations under capital leases	17
Long-term obligations under capital leases	75
Operating Leases
2019	283
2020	208
2021	153
2022	122
2023	92
After 2023	253
Total	$ 1,111