Leases (Maturity of Lease Liabilities) (Details) $ in Millions	Jun. 30, 2019 USD ($)
Operating leases
2019	$ 116
2020	188
2021	156
2022	117
2023	82
Thereafter	98
Total lease payments	757
Less amount representing interest	(90)
Present value of lease liabilities	667
Finance leases
2019	22
2020	38
2021	38
2022	14
2023	3
Thereafter	6
Total lease payments	121
Less amount representing interest	(6)
Present value of lease liabilities	$ 115