Operating Segments Operating Segments Table (Details) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Tower Count		40,000				40,000
Fiber Miles		75,000				75,000
Amortization of prepaid lease purchase price adjustments		$ 5				$ 15
Site Rental		1,260		$ 1,184		3,718		$ 3,507
Services and other		254		191		700		497
Segment Revenues		1,514		1,375		4,418		4,004
Segment site rental cost of operations	[1]	369		355		1,095		1,057
Services and other	[1]	147		119		410		304
Segment selling, general and administrative expenses		150		145		457		418
Stock-based compensation expense						91		79
Depreciation, Amortization and Accretion, Net		389		385		1,176		1,138
Interest expense and amortization of deferred financing costs		173		160		510		478
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		277		169		744		471
Capital expenditures						1,538		1,241
Total Assets		38,344				38,344				$ 32,785
Segment cost of operations share-based compensation [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense		7				21		19
Towers [Member]
Segment Reporting Information [Line Items]
Site Rental		829		782		2,451		2,318
Services and other		250		189		689		489
Segment Revenues		1,079		971		3,140		2,807
Segment site rental cost of operations		218		215		647		641
Services and other		143		115		398		292
Segment cost of operations	[3]	361	[2]	330	[2]	1,045	[4]	933	[4]
Segment site rental gross margin		611		567		1,804		1,677
Segment services gross margin		107		74		291		197
Segment selling, general and administrative expenses		23	[2]	28	[2]	73	[4]	81	[4]
Segment Operating Profit		695		613		2,022		1,793
Capital expenditures		146		123		403		318
Total Assets		22,101		17,694		22,101		17,694
Fiber [Member]
Segment Reporting Information [Line Items]
Site Rental		431		402		1,267		1,189
Services and other		4		2		11		8
Segment Revenues		435		404		1,278		1,197
Segment site rental cost of operations		141		131		418		388
Services and other		2		1		6		6
Segment cost of operations	[3]	143	[2]	132	[2]	424	[4]	394	[4]
Segment site rental gross margin		290		271		849		801
Segment services gross margin		2		1		5		2
Segment selling, general and administrative expenses		49	[2]	45	[2]	147	[4]	131	[4]
Segment Operating Profit		243		227		707		672
Capital expenditures		382		348		1,108		900
Total Assets		15,565		14,326		15,565		14,326
Consolidated Total [Member]
Segment Reporting Information [Line Items]
Site Rental		1,260		1,184		3,718		3,507
Services and other		254		191		700		497
Segment Revenues		1,514		1,375		4,418		4,004
Segment site rental cost of operations		359		346		1,065		1,029
Services and other		145		116		404		298
Segment cost of operations	[3]	504	[2]	462	[2]	1,469	[4]	1,327	[4]
Segment site rental gross margin		901		838		2,653		2,478
Segment services gross margin		109		75		296		199
Segment selling, general and administrative expenses		72	[2]	73	[2]	220	[4]	212	[4]
Segment Operating Profit		938		840		2,729		2,465
Stock-based compensation expense		29		32		90		84
Depreciation, Amortization and Accretion, Net		389		385		1,176		1,138
Interest expense and amortization of deferred financing costs		173		160		510		478
Other expenses to reconcile to income (loss) from continuing operations before income taxes	[5]	14		47		41		153
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		277		169		744		471
Capital expenditures		540		478		1,538		1,241
Total Assets		38,344		32,644		38,344		32,644
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Segment selling, general and administrative expenses		56		47		168		141
Segment Operating Profit
Stock-based compensation expense		29		32		90		84
Depreciation, Amortization and Accretion, Net		389		385		1,176		1,138
Interest expense and amortization of deferred financing costs		173		160		510		478
Other expenses to reconcile to income (loss) from continuing operations before income taxes	[5]	14		47		41		153
Capital expenditures		12		7		27		23
Total Assets		678		624		678		624
Segment G&A share-based compensation [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense		$ 22		$ 25		$ 69		$ 65

[1] Exclusive of depreciation, amortization and accretion shown separately.

[2] Segment cost of operations excludes (1) stock-based compensation of $7 million for both of the three months ended September 30, 2019 and 2018, and (2) prepaid lease purchase price adjustments of $5 million for both of the three months ended September 30, 2019 and 2018. Selling, general and administrative expenses exclude stock-based compensation expense of $22 million and $25 million for the three months ended September 30, 2019 and 2018, respectively.

[3] Exclusive of depreciation, amortization and accretion shown separately.

[4] Segment cost of operations excludes (1) stock-based compensation expense of $21 million and $19 million for the nine months ended September 30, 2019 and 2018, respectively, and (2) prepaid lease purchase price adjustments of $15 million for both of the nine months ended September 30, 2019 and 2018. Selling, general and administrative expenses exclude stock-based compensation expense of $69 million and $65 million for the nine months ended September 30, 2019 and 2018, respectively.

[5] See condensed consolidated statement of operations for further information.