Leases - Maturity of lease liabilities (Details) $ in Millions	Dec. 31, 2019 USD ($)
Operating leases
2020	$ 71
2021	47
2022	35
2023	22
2024	15
2025 and thereafter	41
Total lease payments	231
Less: imputed interest	(28)
Total operating lease liabilities	203
Minimum payments related to leases not yet commenced-Operating leases	76
Finance leases
2020	9
2021	13
2022	11
2023	11
2024	8
2025 and thereafter	30
Total lease payments	82
Less: imputed interest	(12)
Total finance lease liabilities	$ 70