Leases Maturities of Lease Liabilities (Details) $ in Millions	Mar. 31, 2019 USD ($)	[1]
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Due Remainder of Fiscal Year	$ 395
Lessee, Operating Lease, Liability, Payments, Due Year Two	520
Lessee, Operating Lease, Liability, Payments, Due Year Three	514
Lessee, Operating Lease, Liability, Payments, Due Year Four	509
Lessee, Operating Lease, Liability, Payments, Due Year Five	504
Lessee, Operating Lease, Liability, Payments, Due after Year Five	6,304
Lessee, Operating Lease, Liability, Payments, Due	8,746
Inputed Interest	(3,121)
Operating Lease, Liability	$ 5,625

[1] Excludes the Company's contingent payments for operating leases (such as payments based on revenues derived from the communications infrastructure located on the leased asset) as such arrangements are excluded from the Company's operating lease liability. Such contingencies are recognized as expense in the period they are resolved.