Lease maturity (Details) $ in Millions	Sep. 30, 2019 USD ($)
Leases [Abstract]
2019 - Operating Leases	$ 75
2019 - Financing Leases	15
2020 - Operating Leases	218
2020 - Financing Leases	62
2021 - Operating Leases	172
2021 - Financing Leases	63
2022 - Operating Leases	143
2022 - Financing Leases	63
2023 - Operating Leases	107
2023 - Financing Leases	62
Thereafter - Operating Leases	524
Thereafter - Financing Leases	137
Total lease payments - Operating Leases	1,239
Total lease payments - Financing Leases	402
Imputed interest - Operating Leases	(269)
Imputed interest - Financing Leases	(256)
Total - Operating Leases	970
Total - Financing Leases	$ 146