Leases Lessee arrangements - Maturity of lease liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity
2020	$ 185
2021	139
2022	86
2023	64
2024	46
Thereafter	175
Total lease payments	695
Less: Imputed interest	(61)
Total	634
2019	205	$ 205
2020	154	154
2021	111	111
2022	67	67
2023	50	50
Thereafter	185	185
Total	$ 772	$ 772