Leases Lease, Operating and Finance Lease Maturity (Details) $ in Millions	Jun. 30, 2019 USD ($)
Operating and Finance Lease Maturity [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months	$ 184
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Two	191
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Three	178
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Four	160
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Five	140
Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five	544
Lessee, Operating Lease, Liability, Payments, Due	1,397
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(192)
Operating Lease, Liability	1,205
Finance Lease, Liability, Payments, Due in Next Rolling Twelve Months	5
Finance Lease, Liability, Payments, Due in Rolling Year Two	5
Finance Lease, Liability, Payments, Due in Rolling Year Three	5
Finance Lease, Liability, Payments, Due in Rolling Year Four	6
Finance Lease, Liability, Payments, Due in Rolling Year Five	3
Finance Lease, Liability, Payments, Due in Rolling after Year Five	12
Finance Lease, Liability, Payments, Due	36
Finance Lease, Liability, Undiscounted Excess Amount	(9)
Finance Lease, Liability	27
Operating and Finance Lease, Liability, Payments Due in Next Rolling Twelve Months	189
Operating and Finance Lease, Liability, Payments Due in Rolling Year Two	196
Operating and Finance Lease, Liability, Payments Due in Rolling Year Three	183
Operating and Finance Lease, Liability, Payments Due in Rolling Year Four	166
Operating and Finance Lease, Liability, Payments Due in Rolling Year Five	143
Operating and Finance Lease, Liability, Payments Due in Rolling After Year Five	556
Operating and Finance Lease, Liability, Payments, Due	1,433
Operating and Finance Lease, Liability, Undiscounted Excess Amount	(201)
Operating and Finance Lease Liabilities	$ 1,232