Leases Lessee Operating Lease Cost (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 160	[1]
Variable Lease, Cost	32	[2]
Lease, Cost	$ 192	[3]

[1] Represents the Company's operating lease expense related to its ROU assets for the three months ended March 31, 2019.

[2] Represents the Company's expense related to contingent payments for operating leases (such as payments based on revenues derived from the communications infrastructure located on the leased asset) for the three months ended March 31, 2019. Such contingencies are recognized as expense in the period they are resolved.

[3] Excludes those direct operating expenses accounted for pursuant to accounting guidance outside the scope of ASC 842.