Schedule III - Schedule of Real Estate and Depreciation (Details) $ in Millions		12 Months Ended
		Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Amount of Encumbrances	[1]	$ 3,293
Gross Amount of Property Carried		23,854	$ 21,840	$ 20,086
Gross Amount of Accumulated Depreciation Carried		$ (9,382)	(8,338)	$ (7,301)
Tower Count		40,000
Fiber Miles		80,000
Other Acquisitions	[2]	$ 4	5
Communications Infrastructure Construction and Improvements		1,878	1,565
Purchase of land interests		53	56
Sustaining Capital Expenditures		84	85
Other Additions	[3]	101	64
Total Additions		2,120	1,775
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Write-down or Reserve, Amount		(45)	(21)
Cost of Real Estate Sold or Disposed		(106)	(21)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Other Deduction		(61)	0
Depreciation		(1,087)	(1,056)
Amount of Accumulated Depreciation Sold or Disposed		24	18
Other Deductions to Accumulated Depreciation		19	1
Real Estate Period Deductions to Accumulated Depreciation		$ 43	$ 19

[1] (b) Encumbrances are reported at face value, without contemplating the effect of deferred financing costs, discounts or premiums. Certain of the Company's debt is secured by (1) a security interest in substantially all of the applicable issuers' assignable personal property, (2) a pledge of the equity interests in each applicable issuer and (3) a security interest in the applicable issuers' leases with tenants to lease tower space (space licenses).

[2] acquisitions of communications infrastructure.

[3] redominately relates to the purchase of property and equipment under finance leases and installment land purchases.