Lease maturity (Details) $ in Millions	Jun. 30, 2019 USD ($)
Leases [Abstract]
2019 - Operating Leases	$ 151
2019 - Financing Leases	34
2020 - Operating Leases	206
2020 - Financing Leases	65
2021 - Operating Leases	161
2021 - Financing Leases	65
2022 - Operating Leases	125
2022 - Financing Leases	65
2023 - Operating Leases	101
2023 - Financing Leases	65
Thereafter - Operating Leases	524
Thereafter - Financing Leases	144
Total lease payments - Operating Leases	1,268
Total lease payments - Financing Leases	438
Imputed interest - Operating Leases	(293)
Imputed interest - Financing Leases	(284)
Total - Operating Leases	975
Total - Financing Leases	$ 154