Operating Segments Operating Segments Table (Details) $ in Millions		3 Months Ended
		Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Tower Count		40,000
Fiber Miles		70,000
Amortization of prepaid lease purchase price adjustments		$ 5
Segment site rental revenues		1,219	$ 1,153
Services and other revenue		207	146
Segment Revenues		1,426	1,299
Segment site rental cost of operations	[1]	361	347
Services and other costs	[1]	125	86
Segment selling, general and administrative expenses		152	134
Stock-based compensation expense		29	23
Depreciation, Amortization and Accretion, Net		394	374
Interest expense and amortization of deferred financing costs		168	160
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		216	118
Capital expenditures		480	370
Total Assets		37,778		$ 32,785
Segment cost of operations share-based compensation [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense		6	7
Towers [Member]
Segment Reporting Information [Line Items]
Segment site rental revenues		805	764
Services and other revenue		203	142
Segment Revenues		1,008	906
Segment site rental cost of operations		211	211
Services and other costs		121	82
Segment cost of operations	[2],[3]	332	293
Segment site rental gross margin		594	553
Segment network services gross margin		82	60
Segment selling, general and administrative expenses	[3]	26	26
Segment Operating Profit		650	587
Capital expenditures		119	96
Total Assets		22,114	17,868
Small Cells [Member]
Segment Reporting Information [Line Items]
Segment site rental revenues		414	389
Services and other revenue		4	4
Segment Revenues		418	393
Segment site rental cost of operations		140	126
Services and other costs		3	2
Segment cost of operations	[2],[3]	143	128
Segment site rental gross margin		274	263
Segment network services gross margin		1	2
Segment selling, general and administrative expenses	[3]	48	43
Segment Operating Profit		227	222
Capital expenditures		355	262
Total Assets		14,930	13,883
Consolidated Total [Member]
Segment Reporting Information [Line Items]
Segment site rental revenues		1,219	1,153
Services and other revenue		207	146
Segment Revenues		1,426	1,299
Segment site rental cost of operations		351	337
Services and other costs		124	84
Segment cost of operations	[2],[3]	475	421
Segment site rental gross margin		868	816
Segment network services gross margin		83	62
Segment selling, general and administrative expenses	[3]	74	69
Segment Operating Profit		877	809
Stock-based compensation expense		29	26
Depreciation, Amortization and Accretion, Net		394	374
Interest expense and amortization of deferred financing costs		168	160
Other expenses to reconcile to income (loss) from continuing operations before income taxes	[4]	15	85
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		216	118
Capital expenditures		480	370
Total Assets		37,778	32,250
Other [Member]
Segment Reporting Information [Line Items]
Segment selling, general and administrative expenses	[3]	55	46
Segment Operating Profit
Stock-based compensation expense		29	26
Depreciation, Amortization and Accretion, Net		394	374
Interest expense and amortization of deferred financing costs		168	160
Other expenses to reconcile to income (loss) from continuing operations before income taxes	[4]	15	85
Capital expenditures		6	12
Total Assets		734	499
Segment G&A share-based compensation [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense		$ 23	$ 19

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

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

[3] Segment cost of operations for the three months ended March 31, 2019 and 2018 excludes (1) stock-based compensation expense of $6 million and $7 million, respectively, and (2) prepaid lease purchase price adjustments of $5 million, for both periods. For the three months ended March 31, 2019 and 2018 segment selling, general and administrative expenses exclude stock-based compensation expense of $23 million and $19 million, respectively.

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