Leases Lessee Operating Lease Cost (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating Lease, Cost	[1]	$ 162	$ 323
Variable Lease, Cost	[2]	33	65
Lease, Cost	[3]	$ 195	$ 388

[1] Represents the Company's operating lease expense related to its ROU assets for both the three and six months ended June 30, 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 both the three and six months ended June 30, 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.