Leases Leases - Maturity of Lease Liabilities (Details) $ in Millions	Jun. 30, 2019 USD ($)
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 36
Lessee, Operating Lease, Liability, Payments, Due Year Two	70
Lessee, Operating Lease, Liability, Payments, Due Year Three	70
Lessee, Operating Lease, Liability, Payments, Due Year Four	64
Lessee, Operating Lease, Liability, Payments, Due Year Five	62
Lessee, Operating Lease, Liability, Payments, Due after Year Five	892
Lessee, Operating Lease, Liability, Payments, Due	1,194
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(675)
Operating Lease, Liability	$ 519