Crown Castle (CCI) 10-K 25 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 22, 2019	Jun. 30, 2018
Entity Information [Line Items]
Document Fiscal Period Focus	FY
Entity Registrant Name	CROWN CASTLE INTERNATIONAL CORP
Entity Central Index Key	1,051,470
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Amendment Flag	false
Entity Common Stock, Shares Outstanding		415,568,382
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 44.6
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 277	$ 314
Restricted cash	131	121
Receivables, net of allowance of $14 and $14, respectively	501	398
Prepaid expenses	172	162
Other current assets	148	139
Total current assets	1,229	1,134
Deferred site rental receivables	1,366	1,300
Property and equipment, net	13,676	12,933
Goodwill	10,078	10,021
Site rental contracts and tenant relationships, net	5,209	5,626
Other intangible assets, net	307	336
Long-term prepaid rent and other assets, net	920	879
Total assets	32,785	32,229
LIABILITIES AND EQUITY
Accounts payable	313	249
Accrued interest	148	132
Deferred revenues	498	457
Other accrued liabilities	351	339
Current maturities of debt and other obligations	107	115
Total current liabilities	1,417	1,292
Debt and other long-term obligations	16,575	16,044
Other long-term liabilities	2,759	2,554
Total liabilities	20,751	19,890
CCIC stockholders' equity:
Common stock, $0.01 par value; 600 shares authorized; shares issued and outstanding: December 31, 2018—415 and December 31, 2017—406	4	4
6.875% Mandatory Convertible Preferred Stock, Series A, $0.01 par value; 20 shares authorized; shares issued and outstanding: December 31, 2018—2 and December 31, 2017—2; aggregate liquidation value: December 31, 2018—$1,650 and December 31, 2017—$1,650	0	0
Additional paid-in capital	17,767	16,844
Accumulated other comprehensive income (loss)	(5)	(4)
Dividends/distributions in excess of earnings	(5,732)	(4,505)
Total equity	12,034	12,339
Total liabilities and equity	$ 32,785	$ 32,229

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts receivable, current	$ 14	$ 14
6.875% Mandatory Convertible Preferred Stock, Par or Stated Value Per Share (dollars per share)	$ 0.01	$ 0.01
6.875% Mandatory Convertible Preferred Stock, Shares Authorized	20	20
6.875% Mandatory Convertible Preferred Stock, shares issued	2	2
Convertible Preferred Stock, shares outstanding	2	2
Mandatory redemption and aggregate liquidation value, 6.875% Mandatory Convertible Preferred Stock	$ 1,650	$ 1,650
Common stock, par value (dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	600	600
Common stock, shares issued	415	406
Common stock, shares outstanding	415	406

Consolidated Statement of Opera

Consolidated Statement of Operations and Comprehensive Income (Loss) - USD ($) shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Net revenues:
Site rental		$ 4,716		$ 3,669		$ 3,233
Services and other		707		687		688
Net Revenues		5,423		4,356		3,921
Costs of Operations:
Site rental	[1]	1,410		1,144		1,024
Services and other	[1]	437		420		417
Selling, general and administrative		563		426		371
Asset write-down charges		26		17		34
Acquisition and integration costs		27		61		17
Depreciation, amortization and accretion		1,528		1,242		1,109
Total operating expenses		3,991		3,310		2,972
Operating income (loss)		1,432		1,046		949
Interest expense and amortization of deferred financing costs		(642)		(591)		(515)
Gains (losses) on retirement of long-term obligations		(106)	[2]	(4)	[3]	(52)	[4]
Interest income		5		19		1
Other income (expense)		1		1		(9)
Income (loss) before income taxes		690		471		374
Benefit (provision) for income taxes		(19)		(26)		(17)
Net income (loss)		671		445		357
Dividends, Preferred Stock		(113)		(58)		(33)
Net income (loss) attributable to CCIC common stockholders		558		387		324
Net income (loss)		671		445		357
Derivative instruments, net of taxes
Foreign currency translation adjustments		(1)		2		(2)
Total other comprehensive income (loss)	[5]	(1)		2		(2)
Comprehensive income (loss) attributable to CCIC stockholders		$ 670		$ 447		$ 355
Net income (loss) attributable to CCIC common stockholders, per common share:
Basic (in dollars per share)		$ 1.35		$ 1.01		$ 0.95
Diluted (in dollars per share)		$ 1.34		$ 1.01		$ 0.95
Weighted-average common shares outstanding:
Basic (in shares)		413		382		340
Diluted (in shares)		415		383		341
[1]	Exclusive of depreciation, amortization and accretion shown separately.
[2]	Inclusive of the write off of the respective deferred financing costs.
[3]	The losses related to write off of deferred financing costs
[4]	Inclusive of the write off of the respective deferred financing costs.
[5]	See the consolidated statement of operations and comprehensive income (loss) for the components of "total other comprehensive income (loss)".

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Cash flows from operating activities:
Income (Loss) from Continuing Operations		$ 671		$ 445		$ 357
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Depreciation, amortization and accretion		1,528		1,242		1,109
(Gains) losses on retirement of long-term obligations		106	[1]	4	[2]	52	[3]
Gains (Losses) on Settled Swaps		0		0		3
Amortization of deferred financing costs and other non-cash interest		7		9		14
Stock-based compensation expense		103		92		79
Asset write-down charges		26		17		34
Deferred income tax (benefit) provision		2		15		9
Other non-cash adjustments, net		2		(2)		10
Changes in assets and liabilities, excluding the effects of acquisitions:
Increase (decrease) in accrued interest		16		35		30
Increase (decrease) in accounts payable		37		(34)		11
Increase (decrease) in deferred revenues, deferred ground lease payables, other accrued liabilities and other liabilities		223		175		196
Decrease (increase) in receivables		(105)		61		(59)
Decrease (increase) in prepaid expenses, deferred site rental receivables, long-term prepaid rent and other assets		(114)		(16)		(58)
Net cash provided by (used for) operating activities		2,502		2,043		1,787
Cash flows from investing activities:
Payments for acquisitions, net of cash acquired		(42)		(9,260)		(557)
Capital expenditures		(1,741)		(1,228)		(874)
Net (payments) receipts from settled swaps		0		0		8	[4]
Other investing activities, net		(12)		(5)		(6)
Net cash provided by (used for) investing activities		(1,795)		(10,493)		(1,429)
Cash flows from financing activities:
Proceeds from issuance of long-term debt		2,742		3,093		5,201
Principal payments on debt and other long-term obligations		(105)		(119)		(96)
Purchases and redemptions of long-term debt		(2,346)		0		(4,045)
Borrowings under revolving credit facility		1,820		2,820		3,440
Payments under revolving credit facility		(1,725)		(1,840)		(4,565)
Payments for financing costs		(31)		(29)		(42)
Net proceeds from issuance of common stock		841		4,221		1,326
Net proceeds from issuance of preferred stock		0		1,608		0
Purchases of common stock		(34)		(23)		(25)
Dividends/distributions paid on common stock		(1,782)		(1,509)		(1,239)
Dividends paid on preferred stock		(113)		(30)		(44)
Net cash provided by (used for) financing activities		(733)		8,192		(89)
Net increase (decrease) in cash, cash equivalents, and restricted cash from continuing operations		(26)		(258)		269
Net cash provided by (used for) investing activities		0		0		113
Net increase (decrease) in cash and cash equivalents - discontinued operations		0		0		113
Effect of exchange rate changes on cash		(1)		1		0
Cash, cash equivalents, and restricted cash at beginning of period	[5]	440		697		315
Cash, cash equivalents, and restricted cash at end of period	[5]	$ 413		$ 440		$ 697
[1]	Inclusive of the write off of the respective deferred financing costs.
[2]	The losses related to write off of deferred financing costs
[3]	Inclusive of the write off of the respective deferred financing costs.
[4]	In January 2016, the Company received a note receivable payment and settled a corresponding foreign currency swap related to its 2015 sale of CCAL.
[5]	See "Recently Adopted Accounting Pronouncements" in note 2 to the financial statements for a discussion of recently adopted restricted cash guidance, which impacted certain presentations on the consolidated statement of cash flows.

Consolidated Statement of Conve

Consolidated Statement of Convertible Preferred Stock and Equity - USD ($) shares in Millions, $ in Millions		Total	Common Stock [Member]	Additional Paid-in Capital	Foreign Currency Translation Adjustments	Dividends/Distributions in Excess of Earnings	6.875% Mandatory Convertible Preferred Stock [Member]	6.875% Mandatory Convertible Preferred Stock [Member]Preferred Stock [Member]	6.875% Mandatory Convertible Preferred Stock [Member]Additional Paid-in Capital	6.875% Mandatory Convertible Preferred Stock [Member]Dividends/Distributions in Excess of Earnings	Common Stock [Member]	Common Stock [Member]Additional Paid-in Capital	4.50% Mandatory Convertible Preferred Stock [Member]	4.50% Mandatory Convertible Preferred Stock [Member]Preferred Stock [Member]	4.50% Mandatory Convertible Preferred Stock [Member]Dividends/Distributions in Excess of Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding								0						10
Accumulated other Comprehensive Income (Loss), Net of Tax					$ (4)
Balance, value at Dec. 31, 2015		$ 7,091	$ 4	$ 9,549		$ (2,458)		$ 0						$ 0
Balance, (in shares) at Dec. 31, 2015			334
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity, net of forfeitures, value		86		86
Purchases and retirement of capital stock, value		(25)										$ (25)
Conversion of redeemable preferred stock into Common Stock, shares			12
Conversion of Stock, Shares Converted														(10)
Stock Issued During Period, Shares, New Issues			15
Stock Issued During Period, Value, New Issues											$ 1,326	1,326
Other Comprehensive Income (Loss), Net of Tax	[1]	(2)			(2)
Proceeds and Excess Tax Benefit from Share-based Compensation		2		2
Common stock dividends/distributions		(1,245)				(1,245)
Preferred stock dividends													$ (33)		$ (33)
Net income (loss)		357				357
Balance, value at Dec. 31, 2016		7,557	$ 4	10,938		(3,379)		$ 0						$ 0
Balance, (in shares) at Dec. 31, 2016			361
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding								0						0
Accumulated other Comprehensive Income (Loss), Net of Tax		(6)
Stock-based compensation related activity, net of forfeitures, value		100		100
Stock-based compensation related activity, net of forfeitures, shares			1
Purchases and retirement of capital stock, value		(23)										(23)
Stock Issued During Period, Shares, New Issues			44					2
Stock Issued During Period, Value, New Issues							$ 1,608		$ 1,608		4,221	4,221
Other Comprehensive Income (Loss), Net of Tax	[1]	2			2
Common stock dividends/distributions		(1,513)				(1,513)
Preferred stock dividends							(58)			$ (58)
Net income (loss)		445				445
Balance, value at Dec. 31, 2017		$ 12,339	$ 4	16,844		(4,505)		$ 0						$ 0
Balance, (in shares) at Dec. 31, 2017		406	406
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding		2						2						0
Accumulated other Comprehensive Income (Loss), Net of Tax		$ (4)			(4)
Stock-based compensation related activity, net of forfeitures, value		116		116
Purchases of common stock, shares			0.3
Stock-based compensation related activity, net of forfeitures, shares			1
Purchases and retirement of capital stock, value		(34)										(34)
Stock Issued During Period, Shares, New Issues			8
Stock Issued During Period, Value, New Issues											$ 841	$ 841
Other Comprehensive Income (Loss), Net of Tax	[1]	(1)			$ (1)
Common stock dividends/distributions		(1,785)				(1,785)
Preferred stock dividends							$ (113)			$ (113)
Net income (loss)		671				671
Balance, value at Dec. 31, 2018		$ 12,034	$ 4	$ 17,767		$ (5,732)		$ 0						$ 0
Balance, (in shares) at Dec. 31, 2018		415	415
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Convertible Preferred Stock, shares outstanding		2						2						0
Accumulated other Comprehensive Income (Loss), Net of Tax		$ (5)
[1]	See the consolidated statement of operations and comprehensive income (loss) for the components of "total other comprehensive income (loss)".

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2018
Basis of Presentation [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Crown Castle International Corp. and its predecessor, as applicable (together, "CCIC"), and their subsidiaries, collectively referred to herein as the "Company." All significant intercompany balances and transactions have been eliminated in consolidation. As used herein, the term "including," and any variation thereof, means "including without limitation." The use of the word "or" herein is not exclusive. Unless the context suggests otherwise, references to "U.S." are to the United States of America and Puerto Rico, collectively. The Company owns, operates and leases shared communications infrastructure that is geographically dispersed throughout the U.S, including (1) towers and other structures, such as rooftops (collectively, "towers"), and (2) fiber primarily supporting small cell networks ("small cells") and fiber solutions. The Company's towers, fiber and small cells assets are collectively referred to herein as "communications infrastructure," and the Company's customers on its communications infrastructure are referred to herein as "tenants." The Company's core business is providing access, including space or capacity, to its shared communications infrastructure via long-term contracts in various forms, including lease, license, sublease and service agreements (collectively, "contracts"). 53% of the Company's towers are leased or subleased or operated and managed under master leases, subleases, or other agreements with AT&T, Sprint, and T-Mobile. The Company has the option to purchase these towers at the end of their respective lease terms. The Company has no obligation to exercise such purchase options. Additional information concerning these towers is as follows: ◦ 22% of the Company's towers are leased or subleased or operated and managed under a master prepaid lease or other related agreements with AT&T for a weighted-average initial term of approximately 28 years, weighted on Towers site rental gross margin. The Company has the option to purchase the leased and subleased towers from AT&T at the end of the respective lease or sublease terms for aggregate option payments of approximately $4.2 billion , which payments, if exercised, would be due between 2032 and 2048. ◦ 16% of the Company's towers are leased or subleased or operated and managed for an initial period of 32 years (through May 2037) under master leases, subleases, or other agreements with Sprint. The Company has the option to purchase in 2037 all (but not less than all) of the leased and subleased Sprint towers from Sprint for approximately $2.3 billion . ◦ 15% of the Company's towers are leased or subleased or operated and managed under a master prepaid lease or other related agreements with T-Mobile for a weighted-average initial term of approximately 28 years, weighted on Towers site rental gross margin. The Company has the option to purchase the leased and subleased towers from T-Mobile at the end of the respective lease or sublease terms for aggregate option payments of approximately $2.0 billion , which payments, if exercised would be due between 2035 and 2049. In addition, through the acquisition of the rights to approximately 7,100 towers ("T-Mobile Acquisition"), there are another 1% of the Company's towers subject to a lease and sublease or other related arrangements with AT&T. The Company has the option to purchase these towers that it does not otherwise already own at the end of their respective lease terms for aggregate option payments of up to approximately $405 million , which payments, if exercised, would be due prior to 2032 (less than $10 million would be due before 2025). As part of the Company's effort to provide comprehensive communications infrastructure solutions, the Company also offers certain services primarily relating to the Company's towers and small cells, predominately consisting of (1) site development services primarily relating to existing or new tenant equipment installations, including: site acquisition, architectural and engineering, or zoning and permitting (collectively, "site development services") and (2) tenant equipment installation or subsequent augmentations (collectively, "installation services"). The vast majority of the Company's services relate to its Towers segment. The Company operates as a real estate investment trust ("REIT") for U.S. federal income tax purposes. In addition, the Company has certain taxable REIT subsidiaries ("TRSs"). See note 10 . The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The Company has changed its presentation from thousands to millions and, as a result, any necessary rounding adjustments have been made to prior year disclosed amounts.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The following is a discussion of the Company's significant accounting policies in effect for the year ended December 31, 2018. Restricted Cash Restricted cash represents (1) the cash held in reserve by the indenture trustees pursuant to the indenture governing certain of the Company's debt instruments, (2) cash securing performance obligations such as letters of credit, as well as (3) any other cash whose use is limited by contractual provisions. The restriction of rental cash receipts is a critical feature of certain of the Company's debt instruments, due to the applicable indenture trustee's ability to utilize the restricted cash for the payment of (1) debt service costs, (2) ground rents, (3) real estate or personal property taxes, (4) insurance premiums related to towers, (5) other assessments by governmental authorities and potential environmental remediation costs, or (6) a portion of advance rents from tenants. The restricted cash in excess of required reserve balances is subsequently released to the Company in accordance with the terms of the indentures. See note 16 for a reconciliation of cash, cash equivalents and restricted cash. Receivables Allowance An allowance for doubtful accounts is recorded as an offset to accounts receivable. The Company uses judgment in estimating this allowance and considers historical collections, current credit status, or contractual provisions. Additions to the allowance for doubtful accounts are charged either to "site rental costs of operations" or to "services and other costs of operations," as appropriate; and deductions from the allowance are recorded when specific accounts receivable are written off as uncollectible. Lease Accounting General. The Company classifies its leases at inception as either operating leases or capital leases. A lease is classified as a capital lease if at least one of the following criteria is met, subject to certain exceptions noted below: (1) the lease transfers ownership of the leased assets to the lessee, (2) there is a bargain purchase option, (3) the lease term is equal to 75% or more of the economic life of the leased assets, or (4) the present value of the minimum lease payments equals or exceeds 90% of the fair value of the leased assets. Lessee. Leases for land are evaluated for capital lease treatment if at least one of the first two criteria mentioned in the immediately preceding paragraph is present relating to the leased assets. When the Company, as lessee, classifies a lease as a capital lease, it records an asset in an amount equal to the present value of the minimum lease payments under the lease at the beginning of the lease term. Applicable operating leases are recognized on a straight-line basis as discussed under "costs of operations" below. Lessor. If the Company is the lessor of leased property that is part of a larger whole (including a portion of space on a tower) and for which fair value is not objectively determinable, then such a lease is accounted for as an operating lease. As applicable, operating leases are recognized on a straight-line basis as discussed under "Revenue Recognition." Effective January 1, 2019, the Company adopted new lease accounting guidance on the recognition, measurement, presentation and disclosure of leases. See also " Recent Accounting Pronouncements Not Yet Adopted " below for further discussion. Property and Equipment Property and equipment is stated at cost, net of accumulated depreciation. Property and equipment includes land owned in fee and perpetual easements for land, which have no definite life. When the Company purchases fee ownership or perpetual easements for the land previously subject to ground lease, the Company reduces the value recorded as land by the amount of any associated deferred ground lease payable or unamortized above-market leases. Depreciation is computed utilizing the straight-line method at rates based upon the estimated useful lives of the various classes of assets. Depreciation of communications infrastructure is computed with a useful life equal to the shorter of 20 years or the term of the underlying ground lease (including optional renewal periods). Additions, renewals, and improvements are capitalized, while maintenance and repairs are expensed. Labor and interest costs incurred directly related to the construction of certain property and equipment are capitalized during the construction phase of projects. For the years ended December 31, 2018 , 2017 , and 2016 , the Company had $212 million , $92 million , and $86 million in capitalized labor costs, respectively. The carrying value of property and equipment is reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Abandonments and write-offs of property and equipment are recorded to "asset write-down charges" on the Company's consolidated statement of operations and comprehensive income (loss) and were $22 million , $14 million , and $27 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. Asset Retirement Obligations Pursuant to its ground lease, easement and leased facility agreements, the Company records obligations to perform asset retirement activities, including requirements to remove communications infrastructure or remediate the space upon which certain of the Company's communications infrastructure resides. Asset retirement obligations are included in "other long-term liabilities" on the Company's consolidated balance sheet. The liability accretes as a result of the passage of time and the related accretion expense is included in "depreciation, amortization and accretion" on the Company's consolidated statement of operations and comprehensive income (loss). The associated asset retirement costs are capitalized as an additional carrying amount of the related long-lived asset and depreciated over the useful life of such asset. Goodwill Goodwill represents the excess of the purchase price for an acquired business over the allocated value of the related net assets. The Company tests goodwill for impairment on an annual basis, regardless of whether adverse events or changes in circumstances have occurred. The annual test begins with goodwill and all intangible assets being allocated to applicable reporting units. The Company's reporting units are the same as its operating segments (Towers and Fiber). The Company then performs a qualitative assessment to determine whether it is "more likely than not" that the fair value of the reporting units is less than its carrying amount. If it is concluded that it is "more likely than not" that the fair value of a reporting unit is less than its carrying amount, it is necessary to perform the two-step goodwill impairment test. The two-step goodwill impairment test begins with a comparison of the estimated fair value of the reporting unit and the carrying value of the reporting unit. The first step, commonly referred to as a "step-one impairment test," is a screen for potential impairment while the second step measures the amount of impairment if there is an indication from the first step that one exists. The Company's measurement of the fair value for goodwill is based on an estimate of discounted expected future cash flows of the reporting unit. The Company performed its most recent annual goodwill impairment test as of October 1, 2018 , which resulted in no impairments. Intangible Assets Intangible assets are included in "site rental contracts and tenant relationships, net" and "other intangible assets, net" on the Company's consolidated balance sheet and predominately consist of the estimated fair value of the following items recorded in conjunction with acquisitions: (1) site rental contracts and tenant relationships, (2) below-market leases for land interest under the acquired communications infrastructure, or (3) other contractual rights such as trademarks. The site rental contracts and tenant relationships intangible assets are comprised of (1) the current term of the existing leases, (2) the expected exercise of the renewal provisions contained within the existing leases, which automatically occur under contractual provisions, or (3) any associated relationships that are expected to generate value following the expiration of all renewal periods under existing leases. The useful lives of intangible assets are estimated based on the period over which the intangible asset is expected to benefit the Company and gives consideration to the expected useful life of other assets to which the useful life may relate. Amortization expense for intangible assets is computed using the straight-line method over the estimated useful life of each of the intangible assets. The useful life of the site rental contracts and tenant relationships intangible asset is limited by the maximum depreciable life of the communications infrastructure ( 20 years), as a result of the interdependency of the communications infrastructure and site rental leases. In contrast, the site rental contracts and tenant relationships are estimated to provide economic benefits for several decades because of the low rate of tenant cancellations and high rate of renewals experienced to date. Thus, while site rental contracts and tenant relationships are valued based upon the fair value, which includes assumptions regarding both (1) tenants' exercise of optional renewals contained in the acquired leases and (2) renewals of the acquired leases past the contractual term including exercisable options, the site rental contracts and tenant relationships are amortized over a period not to exceed 20 years as a result of the useful life being limited by the depreciable life of the communications infrastructure. The carrying value of other intangible assets with finite useful lives will be reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. The Company has a dual grouping policy for purposes of determining the unit of account for testing impairment of the site rental contracts and tenant relationships intangible assets. First, the Company pools the site rental contracts and tenant relationships with the related communications infrastructure assets into portfolio groups for purposes of determining the unit of account for impairment testing. Second and separately, the Company evaluates the site rental contracts and tenant relationships by significant tenant or by tenant grouping for individually insignificant tenants, as appropriate. If the sum of the estimated future cash flows (undiscounted) expected to result from the use or eventual disposition of an asset is less than the carrying amount of the asset, an impairment loss is recognized. Measurement of an impairment loss is based on the fair value of the asset. Deferred Credits Deferred credits are included in "deferred revenues" and "other long-term liabilities" on the Company's consolidated balance sheet and consist of the estimated fair value of the following items recorded in conjunction with acquisitions: (1) below-market tenant leases for contractual interests with tenants on acquired communications infrastructure, which are amortized to site rental revenues and (2) above-market leases for land interests under the Company's communications infrastructure, which are amortized to site rental cost of operations. Fair value for these deferred credits represents the difference between (1) the stated contractual payments to be made pursuant to the in-place lease and (2) management's estimate of fair market lease rates for each corresponding lease. Deferred credits are measured over a period equal to the estimated remaining economic lease term considering renewal provisions or economics associated with those renewal provisions, to the extent applicable. Deferred credits are amortized over their respected estimated lease terms at the time of acquisition. Deferred Financing Costs Third-party costs incurred to obtain financing, with the exception of costs incurred related to revolving lines of credit, are deferred and are included as a direct deduction from the carrying amount of the related debt liability in "debt and other long-term obligations" on the Company's consolidated balance sheet. Third party costs incurred to obtain financing through a revolving line of credit are deferred and are included in "long-term prepaid rent and other assets, net" on the Company's consolidated balance sheet. Revenue Recognition The Company generates site rental revenues from its core business by providing tenants with access, including space or capacity, to its shared communications infrastructure via long-term contracts in various forms, including lease, license, sublease and service agreements. Providing such access over the length of the contract term represents the Company’s sole performance obligation under its site rental contracts. Site rental revenues. Site rental revenues from the Company's contracts are recognized on a straight-line, ratable basis over the fixed, non-cancelable term of the relevant contract, which generally ranges from five to 15 years for wireless tenants and three to 20 years related to the Company's fiber solutions tenants (including from organizations with high-bandwidth and multi-location demands), regardless of whether the payments from the tenant are received in equal monthly amounts during the life of the contract. Certain of the Company's contracts contain fixed escalation clauses (such as fixed dollar or fixed percentage increases) or inflation-based escalation clauses (such as those tied to the consumer price index ("CPI")). If the payment terms call for fixed escalations, upfront payments, or rent free periods, the revenue is recognized on a straight-line basis over the fixed, non-cancelable term of the agreement. When calculating straight-line rental revenues, the Company considers all fixed elements of tenant contractual escalation provisions, even if such escalation provisions contain a variable element in addition to a minimum. The Company's assets related to straight-line site rental revenues include current amounts of $92 million and $86 million included in "other current assets" and non-current amounts of $1.4 billion and $1.3 billion included in "deferred site rental receivables" for the years ended December 31, 2018 and 2017 , respectively. Amounts billed or received prior to being earned are deferred and reflected in "deferred revenues" and "other long-term liabilities." Amounts to which the Company has an unconditional right to payment, which are related to both satisfied or partially satisfied performance obligations, are recorded within "receivables, net" on the Company's consolidated balance sheet. Services and other revenues. As part of the Company’s effort to provide comprehensive communications infrastructure solutions, the Company offers certain services, primarily relating to its towers and small cells, predominately consisting of (1) site development services and (2) installation services. Upon contract commencement, the Company assesses its services to tenants and identifies performance obligations for each promise to provide a distinct service. The Company may have multiple performance obligations for site development services, which primarily include: structural analysis, zoning, permitting and construction drawings. For each of the above performance obligations, services revenues are recognized at completion of the applicable performance obligation, which represents the point at which the Company believes it has transferred goods or services to the tenant. The revenue recognized is based on an allocation of the transaction price among the performance obligations in a respective contract based on estimated standalone selling price. The volume and mix of site development services may vary among contracts and may include a combination of some or all of the above performance obligations. Payments generally are due within 45 to 60 days and generally do not contain variable-consideration provisions. The Company has one performance obligation for installation services, which is satisfied at the time of the respective installation or augmentation. Since performance obligations are typically satisfied prior to receiving payment from tenants, the unconditional right to payment is recorded within "receivables, net" on the Company’s consolidated balance sheet. The vast majority of the Company’s services relates to the Company’s Towers segment, and generally have a duration of one year or less. Additional information on revenues. As of January 1, 2018 and December 31, 2018, $2.1 billion and $2.3 billion of unrecognized revenue, respectively, was reported in "deferred revenues" and "other non-current liabilities" on our consolidated balance sheet. During the year ended December 31, 2018 , approximately $400 million of the January 1, 2018 unrecognized revenue balance was recognized as revenue. See also " Recently Adopted Accounting Pronouncements " below for further discussion. Costs of Operations Approximately half of the Company's site rental costs of operations expenses consist of Towers ground lease expenses, and the remainder includes fiber access expenses, property taxes, repairs and maintenance expenses, employee compensation or related benefit costs, or utilities. Generally, the ground leases for land are specific to each site and are for an initial term of five years and are renewable for pre-determined periods. The Company also enters into term easements and ground leases in which it prepays the entire term in advance. Fiber access expenses primarily consist of leases of fiber assets and other access agreements to facilitate the Company's communications infrastructure. Ground lease and fiber access expenses are recognized on a ratable basis, regardless of whether the payment terms require the Company to make payments annually, quarterly, monthly, or for the entire term in advance. Certain of the Company's ground lease and fiber access agreements contain fixed escalation clauses (such as fixed dollar or fixed percentage increases) or inflation-based escalation clauses (such as those tied to the CPI). If the payment terms include fixed escalation provisions, the effect of such increases is recognized on a straight-line basis. The Company calculates the straight-line expense using a time period that equals or exceeds the remaining depreciable life of the communications infrastructure asset. Further, when a tenant has exercisable renewal options that would compel the Company to exercise existing renewal options, the Company has straight-lined the expense over a sufficient portion of such renewals to coincide with the final termination of the tenant's renewal options. The Company's non-current liability related to straight-line expense is included in "other long-term liabilities" on the Company's consolidated balance sheet. The Company's assets related to prepaid agreements is included in "prepaid expenses" and "long-term prepaid rent and other assets, net" on the Company's consolidated balance sheet. Services and other costs of operations predominately consist of third-party service providers such as contractors and professional services firms and, to a lesser extent, internal labor costs. Acquisition and Integration Costs Direct or incremental costs related to a business combination transaction are expensed as incurred. Such costs are predominately comprised of severance, retention bonuses payable to employees of an acquired enterprise, temporary employees to assist with the integration of the acquired operations, fees paid for services (such as consulting, accounting, legal, or engineering reviews), and any other costs directly associated with the transaction. These business combination costs are included in "acquisition and integration costs" on the Company's consolidated statement of operations and comprehensive income (loss). For those transactions accounted for as asset acquisitions, these costs are capitalized as part of the purchase price. See note 3 for a discussion of the Company's recent acquisitions. Stock-Based Compensation Restricted Stock Units. The Company records stock-based compensation expense only for those unvested restricted stock units ("RSUs") for which the requisite service is expected to be rendered. The cumulative effect of a change in the estimated number of RSUs for which the requisite service is expected to be or has been rendered is recognized in the period of the change in the estimate. To the extent that the requisite service is rendered, compensation cost for accounting purposes is not reversed; rather, it is recognized regardless of whether or not the awards vest. A discussion of the Company's valuation techniques and related assumptions and estimates used to measure the Company's stock-based compensation is as follows: Valuation. The fair value of RSUs without market conditions is determined based on the number of shares relating to such RSUs and the quoted price of the Company's common stock at the date of grant. The Company estimates the fair value of RSUs with market conditions granted using a Monte Carlo simulation. The Company's determination of the fair value of RSUs with market conditions on the date of grant is affected by its common stock price as well as assumptions regarding a number of highly complex or subjective variables. The determination of fair value using a Monte Carlo simulation requires the input of subjective assumptions, and other reasonable assumptions could provide differing results. Amortization Method. The Company amortizes the fair value of all RSUs on a straight-line basis for each separately vesting tranche of the award (graded vesting schedule) over the requisite service periods. Expected Volatility. The Company estimates the volatility of its common stock at the date of grant based on the historical volatility of its common stock. Expected Dividend Rate. The expected dividend rate at the date of grant is based on the then-current dividend yield. Risk-Free Rate. The Company bases the risk-free rate on the implied yield currently available on U.S. Treasury issues with an equivalent remaining term equal to the expected life of the award. Forfeitures. The Company uses historical data and management's judgment about the future employee turnover rates to estimate the number of shares for which the requisite service period will not be rendered. Interest Expense and Amortization of Deferred Financing Costs The components of interest expense and amortization of deferred financing costs are as follows: Years Ended December 31, 2018 2017 2016 Interest expense on debt obligations $ 635 $ 582 $ 501 Amortization of deferred financing costs and adjustments on long-term debt, net 21 19 19 Capitalized interest (15 ) (12 ) (7 ) Other 1 2 2 Total $ 642 $ 591 $ 515 The Company amortizes deferred financing costs, discounts, premiums, and purchase price adjustments on long-term debt over the estimated term of the related borrowing using the effective interest yield method. Deferred financing costs, discounts or purchase price adjustments are generally presented as a direct reduction to the related debt obligation on the Company's consolidated balance sheet. Income Taxes The Company operates as a REIT for U.S. federal income tax purposes. As a REIT, the Company is generally entitled to a deduction for dividends that it pays and therefore is not subject to U.S. federal corporate income tax on its taxable income that is currently distributed to its stockholders. The Company also may be subject to certain federal, state, local, and foreign taxes on its income and assets, including (1) taxes on any undistributed income, (2) taxes related to the TRSs, (3) franchise taxes, (4) property taxes, and (5) transfer taxes. In addition, the Company could in certain circumstances be required to pay an excise or penalty tax, which could be significant in amount, in order to utilize one or more relief provisions under the Internal Revenue Code of 1986, as amended ("Code"), to maintain qualification for taxation as a REIT. Additionally, the Company has included in TRSs certain other assets and operations. Those TRS assets and operations will continue to be subject, as applicable, to federal and state corporate income taxes or to foreign taxes in the jurisdictions in which such assets and operations are located. The Company's foreign assets and operations (including its tower operations in Puerto Rico) are subject to foreign income taxes in the jurisdictions in which such assets and operations are located, regardless of whether they are included in a TRS or not. For its REIT conversion and certain subsequent acquisitions into the REIT, the Company will be subject to a federal corporate level tax rate (currently 21%) on any gain recognized from the sale of assets occurring within a specified period (generally 5 years) after the transfer date up to the amount of the built in gain that existed on the transfer date, which is based upon the fair market value of those assets in excess of the Company's tax basis on the transfer date. This gain can be offset by any remaining federal net operating loss carryforwards ("NOLs"). For the Company's TRSs, the Company accounts for income taxes using an asset and liability approach, which requires the recognition of deferred income tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company's financial statements or tax returns. Deferred income tax assets and liabilities are determined based on the temporary differences between the financial statement and tax bases of assets and liabilities using enacted tax rates. A valuation allowance is provided on deferred tax assets if it is determined that it is "more likely than not" that the asset will not be realized. The Company records a valuation allowance against deferred tax assets when it is "more likely than not" that some portion or all of the deferred tax asset will not be realized. The Company reviews the recoverability of deferred tax assets each quarter and based upon projections of future taxable income, reversing deferred tax liabilities or other known events that are expected to affect future taxable income, records a valuation allowance for assets that do not meet the "more likely than not" realization threshold. Valuation allowances may be reversed if related deferred tax assets are deemed realizable based upon changes in facts and circumstances that impact the recoverability of the asset. The Company recognizes a tax position if it is "more likely than not" that it will be sustained upon examination. The tax position is measured at the largest amount that is greater than 50 percent likely of being realized upon ultimate settlement. The Company reports penalties and tax-related interest expense as a component of the benefit (provision) for income taxes. As of December 31, 2018 and 2017 , the Company has not recorded any material penalties related to its income tax positions. See note 10 . Per Share Information Basic net income (loss) attributable to CCIC common stockholders, per common share excludes dilution and is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period. For the years ended December 31, 2018 and 2017 diluted net income (loss) attributable to CCIC common stockholders, per common share is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period plus any potential dilutive common share equivalents, including shares issuable upon (1) the vesting of RSUs as determined under the treasury stock method and (2) conversion of the Company's 6.875% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share ("6.875% Convertible Preferred Stock"), as determined under the if-converted method. For the year ended December 31, 2016 , diluted income (loss) attributable to CCIC common stockholders, per common share is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period plus any potential dilutive common share equivalents, including shares issuable upon (1) the vesting of RSUs as determined under the treasury stock method and (2) conversion of the Company's then outstanding 4.50% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share ("4.50% Convertible Preferred Stock"), as determined under the if-converted method. A reconciliation of the numerators and denominators of the basic and diluted per share computations is as follows: Years Ended December 31, 2018 2017 2016 Net income (loss) attributable to CCIC stockholders $ 671 $ 445 $ 357 Dividends on preferred stock (113 ) (58 ) (33 ) Net income (loss) attributable to CCIC common stockholders for basic and diluted computations $ 558 $ 387 $ 324 Weighted-average number of common shares outstanding (in millions): Basic weighted-average number of common stock outstanding 413 382 340 Effect of assumed dilution from potential issuance of common shares relating to RSUs 2 1 1 Diluted weighted-average number of common shares outstanding 415 383 341 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 1.35 $ 1.01 $ 0.95 Diluted $ 1.34 $ 1.01 $ 0.95 Dividends/distributions declared per share of common stock $ 4.28 $ 3.90 $ 3.61 For each of the years ended December 31, 2018 and 2017 , 15 million common share equivalents related to the 6.875% Convertible Preferred Stock were excluded from the dilutive common shares because the impact of the conversion of such preferred stock would be anti-dilutive based on the Company's common stock price at the end of each respective year. See notes 11 and 12 . Fair Values The Company's assets and liabilities recorded at fair value are categorized based upon a fair value hierarchy that ranks the quality and reliability of the information used to determine fair value. The three levels of the fair value hierarchy are (1) Level 1 — quoted prices (unadjusted) in active and accessible markets, (2) Level 2 — observable prices that are based on inputs not quoted in active markets but corroborated by market data, and (3) Level 3 — unobservable inputs and are not corroborated by market data. The Company evaluates fair value hierarchy level classifications quarterly, and transfers between levels are effective at the end of the quarterly period. The fair value of cash and cash equivalents and restricted cash approximate the carrying value. The Company determines the fair value of its debt securities based on indicative quotes (that is non-binding quotes) from brokers that require judgment to interpret market information including implied credit spreads for similar borrowings on recent trades or bid/ask prices or quotes from active markets if applicable. Foreign currency swaps are valued at settlement amounts using observable exchange rates and, if material, reflect an adjustment for the Company's and contract counterparty's credit risk. There were no changes since December 31, 2017 in the Company's valuation techniques used to measure fair values. See note 9 for a further discussion of fair values. Recently Adopted Accounting Pronouncements In May 2014, the FASB released updated guidance regarding the recognition of revenue from contracts with customers not otherwise addressed by specific guidance (commonly referred to as "ASC 606" or "the revenue recognition standard"). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (1) identify the contracts with the customer; (2) identify the performance obligations in the contract; (3) determine the contract price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. This guidance was effective for the Company on January 1, 2018. This guidance was required to be applied, at the Company's election, either (1) retrospectively to each prior reporting period pr

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2018
Acquisitions
Acquisitions	Acquisitions 2016 TDC Acquisition In April 2016, the Company acquired Tower Development Corporation ("TDC"), a portfolio of approximately 330 towers, for approximately $461 million in cash ("TDC Acquisition"). The Company financed the acquisition with cash on hand, cash from borrowings under the Company's senior unsecured revolving credit facility ("2016 Revolver"), and cash from equity issuances under the 2015 ATM Program (see note 11 ). The final purchase price allocation was primarily comprised of tenant relationships of approximately $140 million , property and equipment of approximately $107 million , and goodwill of approximately $211 million . 2017 FiberNet Acquisition On November 1, 2016, the Company announced that it had entered into a definitive agreement to acquire FPL FiberNet Holdings, LLC and certain other subsidiaries of NextEra Energy, Inc. (collectively, "FiberNet") for approximately $1.5 billion in cash, subject to certain limited adjustments ("FiberNet Acquisition"). FiberNet is a fiber services provider in Florida and Texas that, as of the agreement date, owned or had rights to approximately 11,500 route miles of fiber installed or under construction, inclusive of approximately 6,000 route miles in top metro markets. On January 17, 2017 , the Company closed the FiberNet Acquisition, which was financed using proceeds from its November 2016 Common Stock Offering (as defined in note 11 ) and borrowings under the 2016 Revolver (see note 8 ). The final purchase price allocation for the FiberNet Acquisition is shown below. Final Purchase Price Allocation Current assets $ 52 Property and equipment 438 Goodwill (a) 778 Other intangible assets, net (b) 327 Other non-current assets 2 Current liabilities (41 ) Other non-current liabilities (35 ) Net assets acquired (c) $ 1,521 (a) The final purchase price allocation for the FiberNet Acquisition resulted in the recognition of goodwill based on: • the Company's expectation to leverage the FiberNet fiber footprint to support new small cells and fiber solutions, • the complementary nature of the FiberNet fiber to the Company's existing fiber assets and its location in top metro markets where the Company expects to see wireless carrier network investments, • the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and • other intangibles not qualified for separate recognition, including the assembled workforce. (b) Predominantly comprised of site rental contracts and tenant relationships. (c) The vast majority of the assets have been included in the Company's REIT. As such, no deferred taxes were recorded in connection with the FiberNet Acquisition. 2017 Wilcon Acquisition On April 17, 2017 , the Company announced that it had entered into a definitive agreement to acquire Wilcon Holdings LLC ("Wilcon") from Pamlico Holdings and other unit holders of Wilcon for approximately $600 million in cash, subject to certain limited adjustments ("Wilcon Acquisition"). Wilcon is a fiber services provider that owns approximately 1,900 route miles of fiber, primarily in Los Angeles and San Diego. On June 26, 2017 , the Company closed the Wilcon Acquisition, which was financed using proceeds from the May 2017 Common Stock Offering (as defined in note 11 ) and the 4.750% Senior Notes (as defined in note 8 ) offering. The final purchase price of approximately $600 million was primarily comprised of other intangible assets (predominantly comprised of site rental contracts and tenant relationships) of approximately $140 million , property and equipment of approximately $150 million , goodwill of approximately $360 million , offset by deferred revenues of approximately $40 million . The final purchase price allocation for the Wilcon Acquisition resulted in the recognition of goodwill based on (1) the Company's expectation to leverage the Wilcon fiber footprint to support new small cells and fiber solutions, (2) the complementary nature of the Wilcon fiber to the Company's existing fiber assets and its location primarily in Los Angeles and San Diego, where the Company expects to see wireless carrier network investments, (3) the Company's belief that the acquired fiber assets are well positioned to benefit from the continued growth trends in the demand for data, and (4) other intangibles not qualified for separate recognition, including the assembled workforce. 2017 Lightower Acquisition On July 18, 2017 , the Company announced that it had entered into a definitive agreement to acquire LTS Group Holdings LLC ("Lightower") from Berkshire Partners, Pamlico Capital and other investors for approximately $7.1 billion in cash, subject to certain limited adjustments ("Lightower Acquisition"). Lightower owns or has rights to approximately 32,000 route miles of fiber located primarily in top metro markets in the Northeast, including Boston, New York and Philadelphia. On November 1, 2017 , the Company closed the Lightower Acquisition, which was financed using (1) cash on hand, including proceeds from the July 2017 Equity Offerings (as defined in note 11 ) and the August 2017 Senior Notes (as defined in note 8 ) offering, and (2) borrowings under the 2016 Revolver. The final purchase price allocation for the Lightower Acquisition is shown below. Final Purchase Price Allocation Current assets $ 99 Property and equipment 2,194 Goodwill (a) 3,171 Other intangible assets, net (b) 2,177 Other non-current assets 27 Current liabilities (176 ) Other non-current liabilities (342 ) Net assets acquired (c) $ 7,150 (a) The final purchase price allocation for the Lightower Acquisition resulted in the recognition of goodwill based on: • the Company's expectation to leverage the Lightower fiber footprint to support new small cells and fiber solutions , • the complementary nature of the Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments , • the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and • other intangibles not qualified for separate recognition, including the assembled workforce. (b) Predominantly comprised of site rental contracts and tenant relationships. (c) The vast majority of the assets have been included in the Company's REIT. As such, no deferred taxes were recorded in connection with the Lightower Acquisition. Actual and Pro Forma Financial Information Net revenues and net income (loss) attributable to acquisitions completed during the year ended December 31, 2017 are included in the Company's consolidated statements of operations and comprehensive income (loss), since the respective date each acquisition was completed. For the year ended December 31, 2017, the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition (collectively, "2017 Acquisitions") resulted in an increase to consolidated net revenues of $314 million . The unaudited pro forma financial results for the years ended December 31, 2017 and 2016 combine the historical results of the Company, along with the historical results of the 2017 Acquisitions for the respective periods. The following table presents the unaudited pro forma consolidated results of operations of the Company as if each acquisition was completed as of January 1, 2016 for the periods presented below. The unaudited pro forma amounts are presented for illustrative purposes only and are not necessarily indicative of future consolidated results of operations. Twelve Months Ended December 31, 2017 2016 Net revenues $ 5,050 $ 4,865 Income (loss) before income taxes $ 541 (b)(c) $ 367 (b)(c)(d) Benefit (provision) for income taxes $ (29 ) (a) $ (21 ) (a) Net income (loss) $ 512 (b)(c) $ 346 (b)(c)(d) Basic net income (loss) attributable to CCIC common stockholders, per common share $ 0.89 (c)(e) $ 0.51 (c)(e) Diluted net income (loss) attributable to CCIC common stockholders, per common share $ 0.88 (c)(e) $ 0.51 (c)(e) (a) For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to the benefit (provision) for income tax as a result of the Company's REIT status. The vast majority of the assets and related income from the FiberNet Acquisition, the Wilcon Acquisition, and the Lightower Acquisition are included in the Company's REIT. The remaining assets are included in the Company's TRS. For purposes of the unaudited pro forma financial results, an adjustment has been made to reflect the additional tax impact of the income related to the TRS assets. (b) For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to depreciation and amortization of $247 million and $316 million , respectively, related to property and equipment and intangibles recorded as a result of the 2017 Acquisitions. (c) Pro forma amounts include the impact of the interest expense and common stock share issuances associated with the related debt and equity financings for the 2017 Acquisitions (see above and notes 8 and 11 ). (d) Amounts are inclusive of a total of $120 million of Lightower stock-based compensation expense and acquisition and integration costs. (e) Pro forma amounts include the impact of the preferred stock dividends related to the Mandatory Convertible Preferred Stock Offering (as defined in note 11 ) for the Lightower Acquisition (see above and note 11 ).

Revenue (Notes)

Revenue (Notes)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenues The following table is a summary of the contracted amounts owed to the Company by tenants pursuant to site rental contracts in effect as of December 31, 2018. As of December 31, 2018 , the weighted-average remaining term of tenant contracts is approximately five years, exclusive of renewals at the tenant's option. Years ending December 31, 2019 2020 2021 2022 2023 Thereafter Total Contracted amounts $ 3,968 $ 3,761 $ 3,552 $ 3,317 $ 2,587 $ 6,229 $ 23,414

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment The major classes of property and equipment are as follows: Estimated Useful Lives As of December 31, 2018 2017 Land (a) — $ 1,981 $ 1,859 Buildings 40 years 134 119 Communications infrastructure assets 1-20 years 18,709 17,184 Information technology assets and other 2-7 years 443 372 Construction in process — 975 899 Total gross property and equipment 22,242 20,433 Less: accumulated depreciation (8,566 ) (7,500 ) Total property and equipment, net $ 13,676 $ 12,933 (a) Includes land owned in fee and perpetual easements. Depreciation expense for the years ended December 31, 2018 , 2017 and 2016 was $1.1 billion , $915 million and $833 million , respectively. Capital leases and associated leasehold improvements related to gross property and equipment, and accumulated depreciation was $4.4 billion and $1.9 billion , respectively, as of December 31, 2018 . See notes 1 and 2 , including discussion of the Company's prepaid master lease agreements.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill The changes in the carrying value of goodwill for the years ended December 31, 2018 and December 31, 2017 were as follows: Balance as of December 31, 2016 $ 5,758 Additions due to FiberNet Acquisition (a) 778 Additions due to Wilcon Acquisition (a) 358 Additions due to Lightower Acquisition (a) 3,115 Adjustments due to other acquisitions, purchase price allocations and other, net 12 Balance as of December 31, 2017 $ 10,021 Adjustments due to other acquisitions, purchase price allocations and other, net 57 Balance as of December 31, 2018 $ 10,078 (a) The final purchase price allocations for the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition resulted in the recognition of goodwill in the Fiber segment based on: • the Company's expectation to leverage the FiberNet, Wilcon and Lightower fiber footprint to support new small cells and fiber solutions , • the complementary nature of the FiberNet, Wilcon and Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments , • the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and • other intangibles not qualified for separate recognition, including the assembled workforce. See note 3 . Intangibles The following is a summary of the Company's intangible assets. See note 3 for further discussion of the Company's acquisitions. As of December 31, 2018 As of December 31, 2017 Gross Carrying Value (a) Accumulated Amortization Net Book Value Gross Carrying Value Accumulated Amortization Net Book Value Site rental contracts and tenant relationships $ 7,787 $ (2,578 ) $ 5,209 $ 7,782 $ (2,156 ) $ 5,626 Other intangible assets 494 (187 ) 307 504 (168 ) 336 Total $ 8,281 $ (2,765 ) $ 5,516 $ 8,286 $ (2,324 ) $ 5,962 (a) During the year ended December 31, 2018 , intangible assets additions (primarily site rental contracts and tenant relationships) from acquisitions had a weighted average amortization period of approximately 20 years. Amortization expense related to intangible assets is classified as follows on the Company's consolidated statement of operations and comprehensive income (loss): For Years Ended December 31, Classification 2018 2017 2016 Depreciation, amortization and accretion $ 428 $ 314 $ 265 Site rental costs of operations 17 18 19 Total amortization expense $ 445 $ 332 $ 284 The estimated annual amortization expense related to intangible assets (inclusive of those recorded as an increase to "site rental costs of operations") for the years ending December 31, 2019 to 2023 is as follows: Years Ending December 31, 2019 2020 2021 2022 2023 Estimated annual amortization $ 445 $ 444 $ 444 $ 443 $ 443

Other Liabilities (Notes)

Other Liabilities (Notes)	12 Months Ended
	Dec. 31, 2018
Other Liabilities [Abstract]
Other Liabilities	Other Liabilities Other long-term liabilities The following is a summary of the components of "other long-term liabilities" as presented on the Company's consolidated balance sheet. See also note 2 . December 31, 2018 2017 Deferred rental revenues $ 1,267 $ 1,077 Deferred ground lease payable 603 560 Above market leases for land interests, net 181 202 Deferred credits, net 499 532 Asset retirement obligation 192 174 Deferred income tax liabilities 7 5 Other long-term liabilities 10 4 Total $ 2,759 $ 2,554 Pursuant to its ground lease, easement and leased facility agreements, the Company has the obligation to perform certain asset retirement activities, including requirements upon contract termination to remove communications infrastructure or remediate the space upon which its communications infrastructure resides. Accretion expense related to liabilities for retirement obligations amounted to $14 million , $13 million and $11 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. As of December 31, 2018 and 2017 , liabilities for retirement obligations were $192 million and $174 million , respectively, representing the net present value of the estimated expected future cash outlay. As of December 31, 2018 , the estimated undiscounted future cash outlay for asset retirement obligations was approximately $1.1 billion . See note 2 . For the years ended December 31, 2018 , 2017 and 2016 , the Company recorded $18 million , $19 million and $21 million , respectively, as a decrease to "site rental costs of operations" for the amortization of above-market leases for land interests under the Company's towers. The estimated amortization expense related to above-market leases for land interests under the Company's towers recorded to site rental costs of operations for the years ending December 31, 2019 to 2023 is as follows: Years Ending December 31, 2019 2020 2021 2022 2023 Above-market leases for land interests $ 17 $ 16 $ 15 $ 14 $ 13 For the years ended December 31, 2018 , 2017 and 2016 , the Company recognized $69 million , $37 million and $34 million , respectively, in "site rental revenues" related to the amortization of below market tenant leases. The following table summarizes the estimated annual amounts related to below-market tenant leases expected to be amortized into site rental revenues for the years ending December 31, 2019 to 2023 are as follows: Years Ending December 31, 2019 2020 2021 2022 2023 Below-market tenant leases $ 62 $ 55 $ 52 $ 47 $ 43 Other accrued liabilities Other accrued liabilities included accrued payroll and other accrued compensation of $ 157 million and $ 141 million , respectively, as of December 31, 2018 and 2017 .

Debt and Other Obligations

Debt and Other Obligations	12 Months Ended
	Dec. 31, 2018
Debt and Other Obligations [Abstract]
Debt and Other Obligations	Debt and Other Obligations See note 18 for a discussion of the Company's issuance of the February 2019 Senior Notes (as defined in note 18 ) and the application of the net proceeds therefrom. The table below sets forth the Company's debt and other obligations as of December 31, 2018 . Original Issue Date Contractual Maturity Date Outstanding Balance as of December 31, Stated Interest Rate as of December 31, 2018 2017 2018 (a) Tower Revenue Notes, Series 2010-3 Jan. 2010 Jan. 2040 (b)(c) — 1,246 N/A Tower Revenue Notes, Series 2010-6 Aug. 2010 Aug. 2040 (b)(c) — 995 N/A Tower Revenue Notes, Series 2015-1 May 2015 May 2042 (b)(c) 298 297 3.2 % Tower Revenue Notes, Series 2015-2 May 2015 May 2045 (b)(c) 693 692 3.7 % Tower Revenue Notes, Series 2018-1 July 2018 July 2043 (b)(c) 247 — 3.7 % Tower Revenue Notes, Series 2018-2 July 2018 July 2048 (b)(c) 742 — 4.2 % 3.849% Secured Notes Dec. 2012 Apr. 2023 994 993 3.9 % Secured Notes, Series 2009-1, Class A-1 Jul. 2009 Aug. 2019 (d) 12 32 6.3 % Secured Notes, Series 2009-1, Class A-2 Jul. 2009 Aug. 2029 (d) 70 70 9.0 % Capital leases and other obligations Various Various (e) 227 227 Various Total secured debt $ 3,283 $ 4,552 2016 Revolver Jan. 2016 June 2023 1,075 (f) 980 3.8 % (g) 2016 Term Loan A Jan. 2016 June 2023 2,354 2,397 3.8 % (g) 5.250% Senior Notes Oct. 2012 Jan. 2023 1,641 1,639 5.3 % 4.875% Senior Notes Apr. 2014 Apr. 2022 844 842 4.9 % 3.400% Senior Notes Feb./May 2016 Feb. 2021 850 850 3.4 % 4.450% Senior Notes Feb. 2016 Feb. 2026 892 891 4.5 % 3.700% Senior Notes May 2016 June 2026 744 743 3.7 % 2.250% Senior Notes Sept. 2016 Sept. 2021 697 695 2.3 % 4.000% Senior Notes Feb. 2017 Mar. 2027 494 494 4.0 % 4.750% Senior Notes May 2017 May 2047 343 343 4.8 % 3.200% Senior Notes Aug. 2017 Sept. 2024 743 742 3.2 % 3.650% Senior Notes Aug. 2017 Sept. 2027 992 991 3.7 % 3.150% Senior Notes Jan. 2018 July 2023 742 — 3.2 % 3.800% Senior Notes Jan. 2018 Feb. 2028 988 — 3.8 % Total unsecured debt $ 13,399 $ 11,607 Total debt and other obligations 16,682 16,159 Less: current maturities and short-term debt and other current obligations 107 115 Non-current portion of long-term debt and other long-term obligations $ 16,575 $ 16,044 (a) Represents the weighted-average stated interest rate. (b) The Tower Revenue Notes, Series 2010-3 ("January 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2010-6 ("August 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2015-1 and 2015-2 ("May 2015 Tower Revenue Notes") and Tower Revenue Notes, Series 2018-1 and 2018-2 ("July 2018 Tower Revenue Notes") are collectively referred to herein as "Tower Revenue Notes." (c) If the respective series of Tower Revenue Notes are not paid in full on or prior to an applicable anticipated repayment date, then Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes, and additional interest (of an additional approximately 5% per annum) will accrue on the respective Tower Revenue Notes. As of December 31, 2018, the Tower Revenue Notes have principal amounts of $300 million , $250 million , $700 million and $750 million , with anticipated repayment dates in 2022, 2023, 2025 and 2028, respectively. (d) The Secured Notes, Series 2009-1, Class A-1 and Secured Notes, Series 2009-1, Class A-2 are collectively referred to herein as "2009 Securitized Notes." (e) The Company's capital leases and other obligations relate to land, fiber, vehicles, and other assets and bear interest rates ranging up to 10% and mature in periods ranging from less than one year to approximately 30 years . (f) As of December 31, 2018 , the undrawn availability under the 2016 Revolver was $3.2 billion . See note 18 . (g) The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.000% to 1.750% , based on the Company's senior unsecured debt rating. The Company pays a commitment fee ranging from 0.125% to 0.350% , based on the Company's senior unsecured debt rating, per annum on the undrawn available amount under the 2016 Revolver. The credit agreement governing the Company's 2016 Credit Facility contains financial maintenance covenants. The Company is currently in compliance with these financial maintenance covenants, and based upon current expectations, the Company believes it will continue to comply with its financial maintenance covenants. In addition, certain of the Company's debt agreements also contain restrictive covenants that place restrictions on CCIC or its subsidiaries and may limit the Company's ability to, among other things, incur additional debt and liens, purchase the Company's securities, make capital expenditures, dispose of assets, undertake transactions with affiliates, make other investments, pay dividends or distribute excess cash flow. Bank Debt In January 2016, the Company completed the 2016 Credit Facility, which was originally comprised of (1) a $2.5 billion 2016 Revolver maturing in January 2021 , (2) a $2.0 billion 2016 Term Loan A maturing in January 2021 and (3) a $1.0 billion senior unsecured 364-day revolving credit facility ("364-Day Facility") maturing in January 2017. The Company used the net proceeds from the 2016 Credit Facility (1) to repay the then outstanding 2012 Credit Facility and (2) for general corporate purposes. In February 2016, the Company used a portion of the net proceeds from the February 2016 Senior Notes (as defined below) offering to repay in full all outstanding borrowings under the then outstanding 364-Day Facility. In February 2017 , the Company entered into an amendment to the 2016 Credit Facility to (1) incur additional term loans in an aggregate principal amount of $500 million and (2) extend the maturity of both the 2016 Term Loan A and the 2016 Revolver to January 2022 . In August 2017 , the Company entered into an amendment to the 2016 Credit Facility to (1) increase the commitments under the 2016 Revolver by $1.0 billion , for total commitments of $3.5 billion and (2) extend the maturity of the Credit Facility to August 2022 . In June 2018 , the Company entered into an amendment to the 2016 Credit Facility to (1) increase the commitments under the 2016 Revolver by $750 million for total commitments of $4.25 billion and (2) extend the maturity of the 2016 Credit Facility from August 2022 to June 2023 . Securitized Debt The Tower Revenue Notes and the 2009 Securitized Notes (collectively, "Securitized Debt") are obligations of special purpose entities and their direct and indirect subsidiaries (each an "issuer"), all of which are wholly-owned, indirect subsidiaries of CCIC. The Tower Revenue Notes and 2009 Securitized Notes are governed by separate indentures. The May 2015 Tower Revenue Notes and July 2018 Tower Revenue Notes are governed by one indenture and consist of multiple series of notes, each with its own anticipated repayment date. The net proceeds of the January 2010 Tower Revenue Notes and August 2010 Tower Revenue Notes were primarily used to repay the portion of the 2005 Tower Revenue Notes and 2006 Tower Revenue Notes not previously purchased. In April 2014, the Company utilized a portion of the net proceeds from the 4.875% Senior Notes (as defined below) offering to repay $300 million of the January 2010 Tower Revenue Notes which had an anticipated repayment date of January 2015. The net proceeds of the May 2015 Tower Revenue Notes, together with proceeds received from the Company's sale of CCAL, were primarily used to (1) repay $250 million aggregate principal amount of August 2010 Tower Revenue Notes which had an anticipated repayment date of August 2015, (2) repay all of the then outstanding WCP Secured Wireless Site Contracts Revenue Notes, Series 2010-1 ("WCP Securitized Notes"), (3) repay portions of outstanding borrowings under the 2012 Credit Facility and (4) pay related fees and expenses. In July 2018 , the Company issued $1.0 billion aggregate principal amount of Senior Secured Tower Revenue Notes ("July 2018 Tower Revenue Notes"), which were issued pursuant to the existing indenture and have similar terms and security as the Company's existing Tower Revenue Notes. The July 2018 Tower Revenue Notes consist of (1) $250 million aggregate principal amount of 3.720% senior secured tower revenue notes ("3.72% Notes") with an anticipated repayment date of July 2023 and a final maturity of July 2043 and (2) $750 million aggregate principal amount of 4.241% senior secured tower revenue notes ("4.241% Notes") with an anticipated repayment date of July 2028 and a final maturity of July 2048 . The Company used the net proceeds of the July 2018 Tower Revenue Notes, together with cash on hand, to repay all of the previously outstanding Tower Revenue Notes, Series 2010-6 and to pay related fees and expenses. In addition to the July 2018 Tower Revenue Notes described above, in connection with Exchange Act risk retention requirements ("Risk Retention Rules"), an indirect subsidiary of the Company issued and a majority-owned affiliate of the Company purchased approximately $53 million of the Senior Secured Tower Revenue Notes, Series 2018-1, Class R-2028 to retain an eligible horizontal residual interest (as defined in the Risk Retention Rules) in an amount equal to at least 5% of the fair value of the July 2018 Tower Revenue Notes. The Securitized Debt is paid solely from the cash flows generated by the operation of the towers held directly and indirectly by the issuers of the respective Securitized Debt. The Securitized Debt is secured by, among other things, (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). The governing instruments of two indirect subsidiaries ("Crown Atlantic" and "Crown GT") of the issuers of the Tower Revenue Notes generally prevent them from issuing debt and granting liens on their assets without the approval of a subsidiary of Verizon Communications. Consequently, while distributions paid by Crown Atlantic and Crown GT will service the Tower Revenue Notes, the Tower Revenue Notes are not obligations of, nor are the Tower Revenue Notes secured by the cash flows or any other assets of, Crown Atlantic and Crown GT. As of December 31, 2018 , the Securitized Debt was collateralized with personal property and equipment with an aggregate net book value of approximately $1.0 billion , exclusive of Crown Atlantic and Crown GT personal property and equipment. The excess cash flows from the issuers of the Securitized Debt, after the payment of principal, interest, reserves, expenses and management fees, are distributed to the Company in accordance with the terms of the indentures. If the Debt Service Coverage Ratio ("DSCR") (as defined in the applicable governing loan agreement) as of the end of any calendar quarter falls to a certain level, then all excess cash flow of the issuers of the applicable debt instrument will be deposited into a reserve account instead of being released to the Company. The funds in the reserve account will not be released to the Company until the DSCR exceeds a certain level for two consecutive calendar quarters. If the DSCR falls below a certain level as of the end of any calendar quarter, then all cash on deposit in the reserve account along with future excess cash flows of the issuers will be applied to prepay the debt with applicable prepayment consideration. The Company may repay the May 2015 Tower Revenue Notes or the 2009 Securitized Notes in whole or in part at any time after the second anniversary of the applicable issuance date and the July 2018 Tower Revenue Notes from the date of issuance, provided in each case that such prepayment is accompanied by any applicable prepayment consideration. The Securitized Debt has covenants and restrictions customary for rated securitizations, including provisions prohibiting the issuers from incurring additional indebtedness or further encumbering their assets. Bonds—Senior Notes In January 2018 , the Company issued $750 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028 (collectively, "January 2018 Senior Notes"). The Company used the net proceeds of the January 2018 Senior Notes offering to repay (1) in full the January 2010 Tower Revenue Notes and (2) a portion of the outstanding borrowings under the 2016 Revolver. In February 2017 , the Company issued $500 million aggregate principal amount of 4.000% senior unsecured notes due March 2027 ("4.000% Senior Notes"). The Company used the net proceeds from the 4.000% Senior Notes offering to repay a portion of the outstanding borrowings under the 2016 Revolver. In May 2017 , the Company issued $350 million aggregate principal amount of 4.750% senior unsecured notes due May 2047 ("4.750% Senior Notes"). The Company used the net proceeds from the 4.750% Senior Notes offering to partially fund the Wilcon Acquisition and to repay a portion of the outstanding borrowings under the 2016 Revolver. In August 2017 , the Company issued $1.75 billion aggregate principal amount of senior unsecured notes ("August 2017 Senior Notes"), which consisted of (1) $750 million aggregate principal amount of 3.200% senior unsecured notes due September 2024 ("3.200% Senior Notes") and (2) $1.0 billion aggregate principal amount of 3.650% senior unsecured notes due September 2027 ("3.650% Senior Notes"). The Company used the net proceeds from the August 2017 Senior Notes offering to partially fund the Lightower Acquisition and pay related fees and expenses. In February 2016 , the Company issued $1.5 billion aggregate principal amount of senior unsecured notes ("February 2016 Senior Notes"), which consisted of (1) $600 million aggregate principal amount of 3.400% senior notes due February 2021 ("3.400% Senior Notes") and (2) $900 million aggregate principal amount of 4.450% senior unsecured notes due February 2026 ("4.450% Senior Notes"). The Company used the net proceeds from the February 2016 Senior Notes offering, together with cash on hand, to (1) repay in full all outstanding borrowings under the then outstanding 364-Day Facility and (2) repay $500 million of outstanding borrowings under the 2016 Revolver. In May 2016 , the Company issued $1.0 billion aggregate principal amount of senior unsecured notes ("May 2016 Senior Notes"), which consisted of (1) $250 million aggregate principal amount of additional 3.400% Senior Notes pursuant to the same indenture as the 3.400% Senior Notes issued in the February 2016 Senior Notes offering and (2) $750 million aggregate principal amount of 3.700% senior unsecured notes due June 2026 ("3.700% Senior Notes"). The Company used the net proceeds from the May 2016 Senior Notes offering to repay in full the Tower Revenue Notes, Series 2010-2 and Series 2010-5, each issued by certain of its subsidiaries, and to repay a portion of the outstanding borrowings under the 2016 Revolver. In September 2016 , the Company issued $700 million aggregate principal amount of 2.250% senior unsecured notes ("2.250% Senior Notes") due September 2021 . The Company used the net proceeds from the 2.250% Senior Notes offering to (1) repay $500 million aggregate principal amount of 2.381% secured notes due 2017 ("2.381% Secured Notes") issued by certain of its subsidiaries and (2) repay a portion of the outstanding borrowings under the 2016 Revolver. In April 2014 , the Company issued $ 850 million aggregate principal amount of 4.875% senior unsecured notes due April 2022 ("4.875% Senior Notes"). The net proceeds from the offering were approximately $ 839 million , after the deduction of associated fees. The Company utilized the net proceeds from the 4.875% Senior Notes offering (1) to repay $300 million of the January 2010 Tower Revenue Notes with an anticipated repayment date of January 2015 and (2) to redeem all of the then outstanding 7.125% senior unsecured notes due 2019. In October 2012 , the Company issued $1.65 billion aggregate principal amount of 5.250% senior unsecured notes due 2023 ("5.250% Senior Notes"). The Company used the net proceeds from the 5.250% Senior Notes offering to partially fund the T-Mobile Acquisition. Each of the February 2016 Senior Notes, May 2016 Senior Notes, 2.250% Senior Notes, 4.875% Senior Notes, 5.250% Senior Notes, 4.000% Senior Notes, 4.750% Senior Notes, August 2017 Senior Notes and January 2018 Senior Notes (collectively, "Senior Notes") are senior unsecured obligations of the Company and rank equally with all of the Company's existing and future senior unsecured indebtedness, including obligations under the 2016 Credit Facility, and senior to all of the Company's future subordinated indebtedness. The Senior Notes are structurally subordinated to all existing and future liabilities and obligations of the Company's subsidiaries. The Company's subsidiaries are not guarantors of the Senior Notes. CCIC may redeem any of the Senior Notes in whole or in part at any time at a price equal to 100% of the principal amount to be redeemed, plus a make whole premium, if applicable, and accrued and unpaid interest, if any, to the date of redemption. Bonds—Secured Notes In December 2012, the Company issued $1.0 billion aggregate principal amount of 3.849% secured notes due 2023 ("3.849% Secured Notes"). The 2012 Secured Notes were issued and are guaranteed by the same subsidiaries of CCIC that had previously issued and guaranteed the 7.750% senior unsecured notes due 2017 ("7.750% Secured Notes"). The 3.849% Secured Notes are secured by a pledge of the equity interests of such subsidiaries. The 3.849% Secured Notes are not guaranteed by and are not obligations of CCIC or any of its subsidiaries other than the issuers and guarantors of the 3.849% Secured Notes. The 3.849% Secured Notes will be paid solely from the cash flows generated from operations of the towers held directly and indirectly by the issuers and the guarantors of such notes. The Company used the net proceeds from the issuance of the 3.849% Secured Notes to repurchase and redeem the then outstanding 7.750% Secured Notes and a portion of the then outstanding 9.000% senior notes due 2011. The 3.849% Secured Notes may be redeemed at any time at a price equal to 100% of the principal amount, plus a make whole premium, and accrued and unpaid interest, if any to the redemption date. Previously Outstanding Indebtedness See above for a discussion of the Company's recent redemptions and repayments of debt. Contractual Maturities The following are the scheduled contractual maturities of the total debt or other long-term obligations outstanding at December 31, 2018 . These maturities reflect contractual maturity dates and do not consider the principal payments that will commence following the anticipated repayment dates on the Tower Revenue Notes. If the Tower Revenue Notes are not paid in full on or prior to their respective anticipated repayment dates, as applicable, then the Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes and additional interest (of an additional approximately 5% per annum) will accrue on the Tower Revenue Notes. Years Ending December 31, 2019 2020 2021 2022 2023 Thereafter Total Cash Obligations Unamortized Adjustments, Net Total Debt and Other Obligations Outstanding Scheduled contractual maturities $ 107 $ 142 $ 1,702 $ 1,087 $ 6,363 $ 7,390 $ 16,791 $ (109 ) $ 16,682 Debt Purchases and Redemptions The following is a summary of the purchases and redemptions of debt during the years ended December 31, 2018 , 2017 and 2016 . Year Ending December 31, 2018 Principal Amount Cash Paid (a) Gains (losses) (b) Tower Revenue Notes, Series 2010-3 $ 1,250 $ 1,318 $ (71 ) 2016 Term Loan A — — (3 ) Tower Revenues Notes, Series 2010-6 1,000 1,028 (32 ) Total $ 2,250 $ 2,346 $ (106 ) (a) Exclusive of accrued interest. (b) Inclusive of the write off of the respective deferred financing costs. Year Ending December 31, 2017 Principal Amount Cash Paid Gains (losses) (a) 2016 Term Loan A $ — $ — $ (4 ) Total $ — $ — $ (4 ) (a) The losses related to write off of deferred financing costs. Year Ending December 31, 2016 Principal Amount Cash Paid (a) Gains (losses) (b) Revolving Credit Facility under 2012 Credit Facility $ — $ — $ (2 ) Tranche A Term Loans under 2012 Credit Facility 629 629 (2 ) Tranche B Term Loans under 2012 Credit Facility 2,247 2,247 (27 ) Tower Revenue Notes, Series 2010-2 350 353 (3 ) Tower Revenue Notes, Series 2010-5 300 307 (8 ) 2.381% Secured Notes 500 509 (10 ) Total $ 4,026 $ 4,045 $ (52 ) (a) Exclusive of accrued interest. (b) Inclusive of the write off of the respective deferred financing costs.

Fair Value Disclosures

Fair Value Disclosures	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Fair Value Disclosures The following table shows the estimated fair values of the Company's financial instruments, along with the carrying amounts of the related assets (liabilities). See also note 2 . Level in Fair Value Hierarchy December 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Assets: Cash and cash equivalents 1 $ 277 $ 277 $ 314 $ 314 Restricted cash 1 136 136 126 126 Liabilities: Debt and other obligations 2 $ 16,682 $ 16,562 $ 16,159 $ 16,644

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income (loss) from continuing operations before income taxes by geographic area is as follows: Years Ended December 31, 2018 2017 2016 Domestic $ 667 $ 451 $ 349 Foreign (a) 23 20 25 Total $ 690 $ 471 $ 374 (a) Inclusive of income (loss) before income taxes from Puerto Rico. The benefit (provision) for income taxes consists of the following: Years Ended December 31, 2018 2017 2016 Current: Federal $ (5 ) $ (3 ) $ — Foreign (7 ) (6 ) (7 ) State (5 ) (2 ) (1 ) Total current (17 ) (11 ) (8 ) Deferred: Federal — (18 ) (8 ) Foreign (2 ) 3 (1 ) Total deferred (2 ) (15 ) (9 ) Total tax benefit (provision) $ (19 ) $ (26 ) $ (17 ) A reconciliation between the benefit (provision) for income taxes and the amount computed by applying the federal statutory income tax rate to the income (loss) before income taxes is as follows: Years Ended December 31, 2018 2017 2016 Benefit (provision) for income taxes at statutory rate $ (145 ) $ (165 ) $ (131 ) Tax effect of foreign income (losses) 1 — 1 Tax adjustment related to REIT operations 138 159 121 State tax (provision) benefit, net of federal (4 ) (2 ) (1 ) Foreign tax (9 ) (3 ) (7 ) Effects of tax law change (a) — (15 ) — Total $ (19 ) $ (26 ) $ (17 ) (a) Pursuant to the Tax Cuts and Jobs Act, which was signed into law in December 2017, the Company was required to write down its net federal deferred tax asset in the amount of $17 million as a result of the reduction in the federal corporate tax rate offset by a benefit of $2 million related to the refund of the Company's alternative minimum tax credit carryforward. The components of the net deferred income tax assets and liabilities are as follows: December 31, 2018 2017 Deferred income tax liabilities: Property and equipment $ 5 $ 5 Deferred site rental receivable 7 7 Total deferred income tax liabilities 12 12 Deferred income tax assets: Intangible assets 4 5 Net operating loss carryforwards (a) 18 21 Deferred ground lease payable 2 2 Accrued liabilities 5 5 Other 3 1 Valuation allowances (1 ) (1 ) Total deferred income tax assets, net 31 33 Net deferred income tax asset (liabilities) $ 19 $ 21 (a) Balance results from the Company's foreign NOLs. Due to the Company's REIT status, no federal or state NOLs result in the Company recording a deferred income tax asset. See further discussion surrounding the Company's NOL balances below. The Company operates as a REIT for U.S. federal income tax purposes. The components of the net deferred income tax assets (liabilities) are as follows: December 31, 2018 December 31, 2017 Classification Gross Valuation Allowance Net Gross Valuation Allowance Net Federal $ 25 $ — $ 25 $ 25 $ — $ 25 State 1 — 1 1 — 1 Foreign (6 ) (1 ) (7 ) (4 ) (1 ) (5 ) Total $ 20 $ (1 ) $ 19 $ 22 $ (1 ) $ 21 At December 31, 2018 , the Company had U.S. federal and state NOLs of approximately $1.5 billion and $0.6 billion , respectively, which are available to offset future taxable income. These amounts include approximately $237 million of losses related to stock-based compensation. The Company also has foreign NOLs of $50 million . If not utilized, the Company's U.S. federal NOLs expire starting in 2025 and ending in 2036 , the state NOLs expire starting in 2019 and ending in 2036 , and the foreign NOLs expire starting in 2022 and ending in 2037 . The utilization of the NOLs is subject to certain limitations. The Company's U.S. federal and state income tax returns generally remain open to examination by taxing authorities until three years after the applicable NOLs have been used or expired. The remaining valuation allowance relates to certain foreign net deferred tax assets (primarily NOLs). As of December 31, 2018 , there were no unrecognized tax benefits that would impact the effective tax rate, if recognized. From time to time, the Company is subject to examinations by various tax authorities in jurisdictions in which the Company has business operations. At this time, the Company is not subject to an Internal Revenue Service examination. The Australian Taxation Office is conducting an audit of the tax consequences for Australian tax purposes of the Company's sale of CCAL. The Company regularly assesses the likelihood of additional assessments in each of the tax jurisdictions. The Company has no uncertain tax positions as of December 31, 2018. Additionally, the Company does not believe assessments, if any, arising from current or future examination or audits will have a material effect on the Company's financial statements. As of December 31, 2018 , the Company's deferred tax assets are included in "long-term prepaid rent and other assets, net" and the Company's deferred tax liabilities are included in "other long-term liabilities" on the Company's consolidated balance sheet.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' Equity	Equity 2015 "At-the-Market" Stock Offering Program The Company previously maintained an "at-the-market" stock offering program through which it had the right to issue and sell shares of its common stock having an aggregate gross sales price of up to $500 million to or through sales agents ("2015 ATM Program"). The Company sold shares of its common stock under the 2015 ATM Program generating aggregate gross proceeds of approximately $350 million . The Company terminated the 2015 ATM Program in March 2018 with shares of its common stock having an aggregate offering price of approximately $150 million remaining unsold. 2018 "At-The-Market" Stock Offering Program In April 2018, the Company established a new "at-the-market" stock offering program through which it may issue and sell shares of its common stock having an aggregate gross sales price of up to $750 million ("2018 ATM Program"). Sales under the 2018 ATM Program may be made by means of ordinary brokers' transactions on the NYSE or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or, subject to our specific instructions, at negotiated prices. The Company intends to use the net proceeds from any sales under the 2018 ATM Program for general corporate purposes, which (1) may include the funding of future acquisitions or investments or (2) the repayment or repurchase of any outstanding indebtedness. As of December 31, 2018, the Company had $750 million of gross sales of common stock availability remaining under the 2018 ATM Program. May 2017 Common Stock Offering On May 1, 2017 , the Company completed an offering of 4.75 million shares of its common stock, which generated net proceeds of approximately $442 million ("May 2017 Common Stock Offering"). The Company used the net proceeds of the May 2017 Common Stock Offering to partially fund the Wilcon Acquisition. July 2017 Equity Offerings On July 26, 2017 , the Company completed an offering of 40.15 million shares of common stock, including certain additional shares sold pursuant to the underwriters' option, which generated net proceeds of approximately $3.8 billion ("July 2017 Common Stock Offering"). The Company used the net proceeds of the July 2017 Common Stock Offering to partially fund the Lightower Acquisition and pay related fees and expenses. On July 26, 2017 , the Company completed an offering of 1.65 million shares of the Company's 6.875% Convertible Preferred Stock, at $1,000 per share, including certain additional shares sold pursuant to the underwriters' option, which generated net proceeds of approximately $1.6 billion ("Mandatory Convertible Preferred Stock Offering"). The Company used the net proceeds from the Mandatory Convertible Preferred Stock Offering to partially fund the Lightower Acquisition and pay related fees and expenses. The holders of the 6.875% Convertible Preferred Stock are entitled to receive cumulative dividends, when and if declared by the Company's board of directors, at the rate of 6.875% on the liquidation preference of $1,000 per share. The dividends may be paid in cash or, subject to certain limitations, in shares of the Company's common stock or any combination of cash and shares of common stock on February 1, May 1, August 1 and November 1 of each year, commencing on November 1, 2017 and to, and including, August 1, 2020. The terms of the 6.875% Convertible Preferred Stock provide that, unless accumulated dividends have been paid or set aside for payment on all outstanding shares of 6.875% Convertible Preferred Stock for all past dividend periods, no dividends may be declared or paid on common stock. Unless converted earlier, each outstanding share of the 6.875% Convertible Preferred Stock will automatically convert into shares of the Company's common stock on August 1, 2020 into between 8.7260 and 10.4712 shares of the Company's common stock, depending on the applicable market value of the common stock and subject to certain anti-dilution adjustments. At any time prior to August 1, 2020, holders of the 6.875% Convertible Preferred Stock may elect to convert all or a portion of their shares into common stock at the minimum conversion rate of 8.7260 , subject to certain anti-dilution adjustments. The July 2017 Common Stock Offering and Mandatory Convertible Preferred Stock Offering are collectively referred to herein as "July 2017 Equity Offerings." March 2018 Common Stock Offering In March 2018 , the Company completed an offering of 8 million shares of its common stock, which generated net proceeds of $841 million ("March 2018 Equity Financing"). The Company used the net proceeds from the March 2018 Equity Financing for general corporate purposes, including repayment of outstanding indebtedness. Declaration and Payment of Dividends During the year ended December 31, 2018 , the following dividends were declared or paid: Equity Type Declaration Date Record Date Payment Date Dividends Per Share Aggregate Payment Amount (In millions) Common Stock February 21, 2018 March 16, 2018 March 30, 2018 $ 1.05 $ 439 (a) Common Stock May 17, 2018 June 15, 2018 June 29, 2018 $ 1.05 $ 438 (a) Common Stock August 2, 2018 September 14, 2018 September 28, 2018 $ 1.05 $ 438 (a) Common Stock October 15, 2018 December 14, 2018 December 31, 2018 $ 1.125 $ 467 (a) 6.875% Convertible Preferred Stock December 15, 2017 January 15, 2018 February 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock March 19, 2018 April 15, 2018 May 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock June 22, 2018 July 15, 2018 August 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock September 19, 2018 October 15, 2018 November 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock December 11, 2018 January 15, 2019 February 1, 2019 $ 17.1875 $ 28 (a) Inclusive of dividends accrued for holders of unvested RSUs, which will be paid when and if the RSUs vest. See note 18 for further discussion of common stock dividends. Tax Treatment of Dividends The following table summarizes, for income tax purposes, the nature of dividends paid during 2018 on the Company's common stock and 6.875% Convertible Preferred Stock. Equity Type Payment Date Cash Distribution (per share) Ordinary Taxable Dividend (per share) Qualified Taxable Dividend (per share) (a) Section 199A Dividend (per share) Non-Taxable Distribution (per share) Common Stock March 30, 2018 $ 1.05 $ 0.689 $ 0.005 $ 0.684 $ 0.361 Common Stock June 29, 2018 $ 1.05 $ 0.689 $ 0.005 $ 0.684 $ 0.361 Common Stock September 28, 2018 $ 1.05 $ 0.689 $ 0.005 $ 0.684 $ 0.361 Common Stock December 31, 2018 $ 1.125 $ 0.738 $ 0.005 $ 0.733 $ 0.387 6.875% Convertible Preferred Stock February 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — 6.875% Convertible Preferred Stock May 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — 6.875% Convertible Preferred Stock August 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — 6.875% Convertible Preferred Stock November 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — (a) Qualified taxable dividend and section 199A dividend amounts are included in ordinary taxable dividend amounts. Purchases of the Company's Common Stock During each of the years ended December 31, 2018 , 2017 and 2016 , the Company purchased 0.3 million shares of common stock utilizing $34 million , $23 million and $25 million in cash, respectively.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2018
Share-based Compensation [Abstract]
Stock-based Compensation	Stock-based Compensation Stock Compensation Plans Pursuant to a stockholder approved plan, the Company has and is permitted to grant stock-based awards to certain employees, consultants or non-employee directors of the Company and its subsidiaries or affiliates. As of December 31, 2018 , the Company has 10 million shares available for future issuance pursuant to its 2013 Long-Term Incentive Plan ("LTI Plan"). Of these shares remaining available for future issuance, approximately 3 million may be issued pursuant to outstanding RSUs granted under the LTI Plan. Restricted Stock Units The Company issues RSUs to certain executives and employees; each RSU represents a contingent right to receive one share of common stock subject to satisfaction of the applicable vesting terms. The RSUs granted to certain executives and employees include (1) annual performance awards that often include provisions for forfeiture by the employee if certain market performance of the Company's common stock is not achieved, (2) new hire or promotional awards that generally contain only service conditions, or (3) other awards related to specific business initiatives or compensation objectives including retention and merger integration. Generally, such awards vest over periods of approximately 3 years. The following is a summary of the RSU activity during the year ended December 31, 2018 . RSUs (In millions) Outstanding at the beginning of year 3 Granted 1 Vested (1 ) Forfeited — Outstanding at end of year 3 The Company granted approximately 1 million RSUs to the Company's executives and certain other employees for each of the years ended December 31, 2018 , 2017 and 2016 . The weighted-average grant-date fair value per share of the grants for the years ended December 31, 2018 , 2017 and 2016 was $91.52 , $73.52 and $68.53 per share, respectively. The weighted-average requisite service period for the RSUs granted during 2018 was approximately 2.4 years. The approximately 1 million RSUs granted during the year ended December 31, 2018 , were comprised of (1) approximately 0.8 million RSUs that time vest over a three-year period and (2) approximately 0.4 million RSUs to the Company's executives and certain other employees which may vest on the third anniversary of the grant date based upon (1) the Company's total shareholder returns (defined as share price appreciation plus the value of dividends paid during the performance period) and (2) the Company's total shareholder return compared to that of the companies in the Standard & Poor's 500 Index. Certain RSU agreements contain provisions that result in forfeiture by the employee of any unvested shares in the event that the Company's common stock does not achieve certain performance targets. To the extent that the requisite service is rendered, compensation cost for accounting purposes is not reversed; rather, it is recognized regardless of whether or not the market performance target is achieved. The following table summarizes the assumptions used in the Monte Carlo simulation to determine the grant-date fair value for the awards granted during the years ended December 31, 2018 , 2017 and 2016 , respectively, with market conditions. Years Ended December 31, 2018 2017 2016 Risk-free rate 2.4 % 1.5 % 0.9 % Expected volatility 18 % 18 % 19 % Expected dividend rate 3.8 % 4.4 % 4.2 % The Company recognized aggregate stock-based compensation expense related to RSUs of $90 million , $89 million and $76 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. The aggregate unrecognized compensation (net of estimated forfeitures) related to RSUs at December 31, 2018 is $82 million and is estimated to be recognized over a weighted-average period of less than one year . The following table is a summary of the awards vested during the years ended December 31, 2018 , 2017 and 2016 . Years Ended December 31, Total Shares Vested Fair Value on Vesting Date (In millions of shares) 2018 1.0 $ 107 2017 0.7 67 2016 0.8 71 Stock-based Compensation The following table discloses the components of stock-based compensation expense. Years Ended December 31, 2018 2017 2016 Stock-based compensation expense: Site rental costs of operations $ 17 $ 15 $ 14 Services and other costs of operations 8 5 8 Selling, general and administrative expenses 83 76 75 Total stock-based compensation $ 108 $ 96 $ 97

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is involved in various claims, lawsuits, or proceedings arising in the ordinary course of business. While there are uncertainties inherent in the ultimate outcome of such matters and it is impossible to presently determine the ultimate costs or losses that may be incurred, if any, management believes the resolution of such uncertainties and the incurrence of such costs should not have a material adverse effect on the Company's consolidated financial position or results of operations. Additionally, the Company and certain of its subsidiaries are contingently liable for commitments or performance guarantees arising in the ordinary course of business, including certain letters of credit or surety bonds. See note 14 for a discussion of the operating lease commitments. In addition, see note 1 for a discussion of the Company's option to purchase approximately 53% of its towers at the end of their respective lease terms. The Company has no obligation to exercise such purchase options.

Leases

Leases	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Leases	Operating Leases Tenant Leases See note 4 for further information regarding the contractual amounts (including tenant leases) owed to the Company pursuant to agreements in effect as of December 31, 2018. Operating Leases The following table is a summary of rental cash payments owed by the Company, as lessee, to landlords pursuant to contractual agreements in effect as of December 31, 2018 . The Company is obligated under non-cancelable operating leases for land interests under 74% of its towers. The majority of these lease agreements have (1) certain termination rights that provide for cancellation after a notice period, (2) multiple renewal options at the Company's option, and (3) annual escalations. Lease agreements may also contain provisions for a contingent payment based on revenues or the gross margin derived from the communications infrastructure located on the leased land interest. Approximately 90% of our Towers site rental gross margin and more than 75% of our Towers site rental gross margin is derived from towers that reside on land that we own or control for greater than 10 and 20 years, respectively. The operating lease payments included in the table below include payments for certain renewal periods at the Company's option that are reasonably assured to be exercised and an estimate of contingent payments based on revenues and gross margins derived from existing tenant leases. Years Ending December 31, 2019 2020 2021 2022 2023 Thereafter Total Operating leases $ 640 $ 631 $ 628 $ 623 $ 619 $ 8,054 $ 11,195 Rental expense from operating leases was $751 million , $710 million , and $678 million , respectively, for the years ended December 31, 2018 , 2017 , and 2016 . The rental expense was inclusive of contingent payments based on revenues or gross margin derived from the communications infrastructure located on the leased land interests of $108 million , $100 million , and $97 million , respectively, for the years ended December 31, 2018 , 2017 , and 2016 . Effective January 1, 2019, the Company adopted new lease accounting guidance on the recognition, measurement, presentation and disclosure of leases. See note 2 for further discussion.

Operating Segments and Concentr

Operating Segments and Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating Segments and Concentrations of Credit Risks	Operating Segments and Concentrations of Credit Risk Operating Segments The Company's operating segments consists of (1) Towers and (2) Fiber. The Towers segment provides access, including space or capacity, to the Company's approximately 40,000 towers geographically dispersed throughout the U.S. The Towers segment also reflects certain services relating to the Company's towers, consisting of site development services and installation services. The Fiber segment provides access, including space or capacity, to the Company's approximately 65,000 route miles of fiber primarily supporting small cells and fiber solutions geographically dispersed through out the U.S. The measurement of profit or loss used by the Company's chief operating decision maker ("CODM") to evaluate the performance of its operating segments are (1) segment site rental gross margin, (2) segment services and other gross margin and (3) segment operating profit. The Company defines segment site rental gross margin as segment site rental revenues less segment site rental cost of operations, which excludes stock-based compensation expense and prepaid lease purchase price adjustments recorded in consolidated cost of operations. The Company defines segment services and other gross margin as segment services and other revenues less segment services and other cost of operations, which excludes stock-based compensation expense recorded in consolidated cost of operations. The Company defines segment operating profit as segment site rental gross margin plus segment services and other gross margin, less selling, general and administrative expenses attributable to the respective segment. All of these measurements of profit or loss are exclusive of depreciation, amortization and accretion, which are shown separately. Costs that are directly attributable to Towers and Fiber are assigned to those respective segments. The "Other" column (1) represents amounts excluded from specific segments, such as asset write-down charges, acquisition and integration costs, depreciation, amortization and accretion, amortization of prepaid lease purchase price adjustments, interest expense and amortization of deferred financing costs, gains (losses) on retirement of long-term obligations, net gain (loss) on interest rate swaps, gains (losses) on foreign currency swaps, interest income, other income (expense), income (loss) from discontinued operations, and stock-based compensation expense and (2) reconciles segment operating profit to income (loss) before income taxes, as the amounts are not utilized in assessing each segment's performance. The "Other" total assets balance includes corporate assets such as cash and cash equivalents which have not been allocated to specific segments. There are no significant revenues resulting from transactions between the Company's operating segments. Year Ended December 31, 2018 Towers Fiber Other Consolidated Total Segment site rental revenues $ 3,116 $ 1,600 $ 4,716 Segment services and other revenues 691 16 707 Segment revenues 3,807 1,616 5,423 Segment site rental cost of operations 848 525 1,373 Segment services and other cost of operations 418 11 429 Segment cost of operations (a)(b) 1,266 536 1,802 Segment site rental gross margin 2,268 1,075 3,343 Segment services and other gross margin 273 5 278 Segment selling, general and administrative expenses (b) 110 179 289 Segment operating profit (loss) 2,431 901 3,332 Other selling, general and administrative expenses (b) $ 191 191 Stock-based compensation expense 108 108 Depreciation, amortization and accretion 1,528 1,528 Interest expense and amortization of deferred financing costs 642 642 Other (income) expenses to reconcile to income (loss) before income taxes (c) 173 173 Income (loss) before income taxes $ 690 Capital expenditures $ 442 $ 1,264 $ 35 $ 1,741 Total assets (at year end) $ 17,667 $ 14,512 $ 606 $ 32,785 Total goodwill (at year end) $ 5,127 $ 4,951 $ — $ 10,078 (a) Exclusive of depreciation, amortization and accretion shown separately (b) Segment cost of operations for the year ended December 31, 2018 excludes (1) stock-based compensation expense of $25 million and (2) prepaid lease purchase price adjustments of $20 million For the year ended December 31, 2018 , Segment selling, general and administrative expenses exclude stock-based compensation expense of $83 million . (c) See consolidated statement of operations for further information. Year Ended December 31, 2017 Towers Fiber Other Consolidated Total Segment site rental revenues $ 2,900 $ 769 $ 3,669 Segment services and other revenues 637 50 687 Segment revenues 3,537 819 4,356 Segment site rental cost of operations 845 264 1,109 Segment services and other cost of operations 374 41 415 Segment cost of operations (a)(b) 1,219 305 1,524 Segment site rental gross margin 2,055 505 2,560 Segment services and other gross margin 263 9 272 Segment selling, general and administrative expenses (b) 94 89 183 Segment operating profit (loss) 2,224 425 2,649 Other selling, general and administrative expenses (b) $ 167 167 Stock-based compensation expense 96 96 Depreciation, amortization and accretion 1,242 1,242 Interest expense and amortization of deferred financing costs 591 591 Other (income) expenses to reconcile to income (loss) before income taxes (c) 82 82 Income (loss) before income taxes $ 471 Capital expenditures $ 418 $ 782 $ 28 $ 1,228 Total assets (at year end) $ 17,941 $ 13,669 $ 619 $ 32,229 Total goodwill (at year end) $ 5,127 $ 4,894 $ — $ 10,021 (a) Exclusive of depreciation, amortization and accretion shown separately (b) Segment cost of operations for the year ended December 31, 2017 excludes (1) stock-based compensation expense of $20 million and (2) prepaid lease purchase price adjustments of $20 million . For the year ended December 31, 2017 . Segment selling, general and administrative expenses exclude stock-based compensation expense of $76 million . (c) See consolidated statement of operations for further information. Year Ended December 31, 2016 Towers Fiber Other Consolidated Total Segment site rental revenues $ 2,831 $ 402 $ 3,233 Segment services and other revenues 604 84 688 Segment revenues 3,435 486 3,921 Segment site rental cost of operations 840 147 987 Segment services and other cost of operations 345 65 410 Segment cost of operations (a)(b) 1,185 212 1,397 Segment site rental gross margin 1,991 255 2,246 Segment services and other gross margin 259 19 278 Segment selling, general and administrative expenses (b) 93 60 153 Segment operating profit (loss) 2,157 214 2,371 Other selling, general and administrative expenses (b) $ 143 143 Stock-based compensation expense 97 97 Depreciation, amortization and accretion 1,109 1,109 Interest expense and amortization of deferred financing costs 515 515 Other (income) expenses to reconcile to income (loss) before income taxes (c) 133 133 Income (loss) before income taxes $ 374 Capital expenditures $ 430 $ 409 $ 35 $ 874 Total assets (at year end) $ 18,395 $ 3,441 $ 839 $ 22,675 Total goodwill (at year end) $ 5,115 $ 643 $ — $ 5,758 (a) Exclusive of depreciation, amortization and accretion shown separately (b) Segment cost of operations for the year ended December 31, 2016 excludes (1) stock-based compensation expense of $22 million and (2) prepaid lease purchase price adjustments of $22 million . For the year ended December 31, 2016 , Segment selling, general and administrative expenses exclude stock-based compensation expense of $75 million for the year ended . (c) See consolidated statement of operations for further information. Major Tenants The following table summarizes the percentage of the consolidated revenues for those tenants accounting for more than 10% of the consolidated revenues. Years Ended December 31, 2018 2017 2016 AT&T 20 % 25 % 27 % T-Mobile 20 % 22 % 23 % Verizon Wireless 20 % 22 % 22 % Sprint 15 % 17 % 16 % Total 75 % 86 % 88 % Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash and cash equivalents, restricted cash and trade receivables. The Company mitigates its risk with respect to cash and cash equivalents by maintaining such deposits at high credit quality financial institutions and monitoring the credit ratings of those institutions. The Company's restricted cash is predominately held and directed by a trustee (see note 2 ). The Company derives the largest portion of its revenues from tenants in the wireless industry. The Company also has a concentration in its volume of business with AT&T, T-Mobile, Verizon Wireless and Sprint or their agents that accounts for a significant portion of the Company's revenues, receivables and deferred site rental receivables. The Company mitigates its concentrations of credit risk with respect to trade receivables by actively monitoring the creditworthiness of its tenants, the use of tenant leases with contractually determinable payment terms or proactive management of past due balances.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Cash Flow, Supplemental Disclosures [Text Block]	Supplemental Cash Flow Information The following table is a summary of the supplemental cash flow information during the years ended December 31, 2018 , 2017 and 2016 . Years Ended December 31, 2018 2017 2016 Supplemental disclosure of cash flow information: Interest paid $ 619 $ 547 $ 471 Income taxes paid 17 16 14 Supplemental disclosure of non-cash investing and financing activities: Increase in accounts payable for purchases of property and equipment 29 2 18 Purchase of property and equipment under capital leases and installment land purchases 40 32 52 Increase in preferred stock dividends accrued but not paid (see note 11) — 28 — The reconciliation of cash, cash equivalents, and restricted cash reported within various lines on the consolidated balance sheet to amounts reported in the consolidated statement of cash flows is shown below. As of December 31, 2018 2017 2016 Cash and cash equivalents $ 277 $ 314 $ 568 Restricted cash, current 131 121 125 Restricted cash reported within long-term prepaid rent and other assets, net 5 5 5 Cash, cash equivalents and restricted cash $ 413 $ 440 $ 698

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Quarterly Financial Information (Unaudited)	Quarterly Financial Information (Unaudited) Summary quarterly financial information for the years ended December 31, 2018 and 2017 is as follows: Three Months Ended (a) March 31 June 30 September 30 December 31 2018: Net revenues $ 1,299 $ 1,330 $ 1,375 $ 1,419 Operating income (loss) 349 345 359 379 Gains (losses) on retirement of long-term obligations (71 ) (3 ) (32 ) — Benefit (provision) for income taxes (4 ) (5 ) (5 ) (5 ) Net income (loss) attributable to CCIC stockholders 86 152 136 185 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 0.21 $ 0.37 $ 0.33 $ 0.45 Diluted $ 0.21 $ 0.36 $ 0.33 $ 0.44 Three Months Ended (a) March 31 June 30 September 30 December 31 2017: Net revenues $ 1,016 $ 1,038 $ 1,063 $ 1,238 Operating income (loss) 257 259 261 267 Gains (losses) on retirement of long-term obligations (4 ) — — — Benefit (provision) for income taxes (4 ) (5 ) (2 ) (15 ) Net income (loss) attributable to CCIC stockholders 119 112 115 98 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 0.33 $ 0.31 $ 0.22 $ 0.17 Diluted $ 0.33 $ 0.31 $ 0.21 $ 0.17 (a) The sum of quarterly information may not agree to year to date information due to rounding.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	18. Subsequent Events February 2019 Senior Notes Offering On February 11, 2019 , the Company issued $1.0 billion aggregate principal amount of senior unsecured notes ("February 2019 Senior Notes"), which consisted of (1) $600 million aggregate principal amount of 4.300% senior unsecured notes due February 2029 and (2) $400 million aggregate principal amount of 5.200% senior unsecured notes due February 2049 . The Company used the net proceeds of the February 2019 Senior Notes offering to repay a portion of the outstanding borrowings under the 2016 Revolver. Common Stock Dividend On February 21, 2019 , the Company's board of directors declared a quarterly cash dividend of $1.125 per common share. The quarterly dividend will be paid on March 29, 2019 to common stockholders of record as of March 15, 2019 .

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
Schedule II Valuation and Qualifying Accounts
Schedule II - Valuation and Qualifying Accounts Disclosure [Text Block]	Additions Deductions Balance at Beginning of Year Charged to Operations Credited to Operations Written Off Effect of Exchange Rate Changes Other Adjustments Balance at End of Year Allowance for Doubtful Accounts Receivable: 2018 $ 14 $ 4 $ — $ (4 ) $ — $ — $ 14 2017 $ 11 $ 4 $ — $ (5 ) $ — $ 4 (a) $ 14 2016 $ 10 $ 5 $ — $ (4 ) $ — $ — $ 11 (a) Represents the allowance for doubtful accounts reflected in the preliminary purchase price allocations for the 2017 Acquisitions. See note 3 . Additions Deductions Balance at Beginning of Year Charged to Operations Charged to Additional Paid-in Capital and Other Comprehensive Income Credited to Operations Credited to Additional Paid-in Capital and Other Comprehensive Income Other Adjustments (a) Balance at End of Year Deferred Tax Valuation Allowance: 2018 $ 1 $ — $ — $ — $ — $ — $ 1 2017 $ 7 $ — $ — $ (6 ) $ — $ — $ 1 2016 $ 2 $ 1 $ — $ (2 ) $ — $ 6 $ 7 (a) Inclusive of (1) the effects of acquisitions and (2) the inclusion of small cells in the REIT in January 2016.

Schedule III - Schedule of Real

Schedule III - Schedule of Real Estate and Depreciation (Notes)	12 Months Ended
	Dec. 31, 2018
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 Disclosure [Text Block]	Description Encumbrances Initial Cost to Company Cost Capitalized Subsequent to Acquisition Gross Amount Carried at Close of Current Period Accumulated Depreciation at Close of Current Period Date of Construction Date Acquired Life on Which Depreciation in Latest Income Statement is Computed Communications infrastructure (1) $ 3,311 (2) (3) (3) $ 21,866 $ (8,341 ) Various Various Up to 20 years (1) Includes approximately 40,000 towers and 65,000 route miles of fiber. No single asset exceeds 5% of the aggregate gross amounts at which the assets were carried at the close of the period set forth in the table above. (2) 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). (3) The Company has omitted this information, as it would be impracticable to compile such information on an asset-by-asset basis. 2018 2017 Gross amount at beginning $ 20,110 $ 16,121 Additions during period: Acquisitions through foreclosure — — Other acquisitions (1)(2) 5 2,788 Communications infrastructure construction and improvements 1,567 1,063 Purchase of land interests 56 81 Sustaining capital expenditures 85 56 Other (3) 64 46 Total additions 1,777 4,034 Deductions during period: Cost of real estate sold or disposed (21 ) (45 ) Other — — Total deductions: (21 ) (45 ) Balance at end $ 21,866 $ 20,110 (1) Inclusive of changes between the final purchase price allocation and the preliminary purchase price allocations. (2) Includes acquisitions of communications infrastructure. (3) Predominately relates to the purchase of property and equipment under capital leases and installment land purchases. 2018 2017 Gross amount of accumulated depreciation at beginning $ (7,303 ) $ (6,446 ) Additions during period: Depreciation (1,057 ) (890 ) Total additions (1,057 ) (890 ) Deductions during period: Amount for assets sold or disposed 18 26 Other 1 7 Total deductions 19 33 Balance at end $ (8,341 ) $ (7,303 )

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Restricted Cash	Restricted Cash Restricted cash represents (1) the cash held in reserve by the indenture trustees pursuant to the indenture governing certain of the Company's debt instruments, (2) cash securing performance obligations such as letters of credit, as well as (3) any other cash whose use is limited by contractual provisions. The restriction of rental cash receipts is a critical feature of certain of the Company's debt instruments, due to the applicable indenture trustee's ability to utilize the restricted cash for the payment of (1) debt service costs, (2) ground rents, (3) real estate or personal property taxes, (4) insurance premiums related to towers, (5) other assessments by governmental authorities and potential environmental remediation costs, or (6) a portion of advance rents from tenants. The restricted cash in excess of required reserve balances is subsequently released to the Company in accordance with the terms of the indentures. See note 16 for a reconciliation of cash, cash equivalents and restricted cash.
Receivables Allowance	Receivables Allowance An allowance for doubtful accounts is recorded as an offset to accounts receivable. The Company uses judgment in estimating this allowance and considers historical collections, current credit status, or contractual provisions. Additions to the allowance for doubtful accounts are charged either to "site rental costs of operations" or to "services and other costs of operations," as appropriate; and deductions from the allowance are recorded when specific accounts receivable are written off as uncollectible.
General, Leases [Policy Text Block]	Lease Accounting General. The Company classifies its leases at inception as either operating leases or capital leases. A lease is classified as a capital lease if at least one of the following criteria is met, subject to certain exceptions noted below: (1) the lease transfers ownership of the leased assets to the lessee, (2) there is a bargain purchase option, (3) the lease term is equal to 75% or more of the economic life of the leased assets, or (4) the present value of the minimum lease payments equals or exceeds 90% of the fair value of the leased assets.
Lessee, Leases [Policy Text Block]	Lessee. Leases for land are evaluated for capital lease treatment if at least one of the first two criteria mentioned in the immediately preceding paragraph is present relating to the leased assets. When the Company, as lessee, classifies a lease as a capital lease, it records an asset in an amount equal to the present value of the minimum lease payments under the lease at the beginning of the lease term. Applicable operating leases are recognized on a straight-line basis as discussed under "costs of operations" below.
Lease, Policy	Lessor. If the Company is the lessor of leased property that is part of a larger whole (including a portion of space on a tower) and for which fair value is not objectively determinable, then such a lease is accounted for as an operating lease. As applicable, operating leases are recognized on a straight-line basis as discussed under "Revenue Recognition." Effective January 1, 2019, the Company adopted new lease accounting guidance on the recognition, measurement, presentation and disclosure of leases. See also " Recent Accounting Pronouncements Not Yet Adopted " below for further discussion.
Property and Equipment	Property and Equipment Property and equipment is stated at cost, net of accumulated depreciation. Property and equipment includes land owned in fee and perpetual easements for land, which have no definite life. When the Company purchases fee ownership or perpetual easements for the land previously subject to ground lease, the Company reduces the value recorded as land by the amount of any associated deferred ground lease payable or unamortized above-market leases. Depreciation is computed utilizing the straight-line method at rates based upon the estimated useful lives of the various classes of assets. Depreciation of communications infrastructure is computed with a useful life equal to the shorter of 20 years or the term of the underlying ground lease (including optional renewal periods). Additions, renewals, and improvements are capitalized, while maintenance and repairs are expensed. Labor and interest costs incurred directly related to the construction of certain property and equipment are capitalized during the construction phase of projects. For the years ended December 31, 2018 , 2017 , and 2016 , the Company had $212 million , $92 million , and $86 million in capitalized labor costs, respectively. The carrying value of property and equipment is reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Abandonments and write-offs of property and equipment are recorded to "asset write-down charges" on the Company's consolidated statement of operations and comprehensive income (loss) and were $22 million , $14 million , and $27 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively.
Asset Retirement Obligations	Asset Retirement Obligations Pursuant to its ground lease, easement and leased facility agreements, the Company records obligations to perform asset retirement activities, including requirements to remove communications infrastructure or remediate the space upon which certain of the Company's communications infrastructure resides. Asset retirement obligations are included in "other long-term liabilities" on the Company's consolidated balance sheet. The liability accretes as a result of the passage of time and the related accretion expense is included in "depreciation, amortization and accretion" on the Company's consolidated statement of operations and comprehensive income (loss). The associated asset retirement costs are capitalized as an additional carrying amount of the related long-lived asset and depreciated over the useful life of such asset.
Goodwill	Goodwill Goodwill represents the excess of the purchase price for an acquired business over the allocated value of the related net assets. The Company tests goodwill for impairment on an annual basis, regardless of whether adverse events or changes in circumstances have occurred. The annual test begins with goodwill and all intangible assets being allocated to applicable reporting units. The Company's reporting units are the same as its operating segments (Towers and Fiber). The Company then performs a qualitative assessment to determine whether it is "more likely than not" that the fair value of the reporting units is less than its carrying amount. If it is concluded that it is "more likely than not" that the fair value of a reporting unit is less than its carrying amount, it is necessary to perform the two-step goodwill impairment test. The two-step goodwill impairment test begins with a comparison of the estimated fair value of the reporting unit and the carrying value of the reporting unit. The first step, commonly referred to as a "step-one impairment test," is a screen for potential impairment while the second step measures the amount of impairment if there is an indication from the first step that one exists. The Company's measurement of the fair value for goodwill is based on an estimate of discounted expected future cash flows of the reporting unit. The Company performed its most recent annual goodwill impairment test as of October 1, 2018 , which resulted in no impairments.
Intangible Assets	Intangible Assets Intangible assets are included in "site rental contracts and tenant relationships, net" and "other intangible assets, net" on the Company's consolidated balance sheet and predominately consist of the estimated fair value of the following items recorded in conjunction with acquisitions: (1) site rental contracts and tenant relationships, (2) below-market leases for land interest under the acquired communications infrastructure, or (3) other contractual rights such as trademarks. The site rental contracts and tenant relationships intangible assets are comprised of (1) the current term of the existing leases, (2) the expected exercise of the renewal provisions contained within the existing leases, which automatically occur under contractual provisions, or (3) any associated relationships that are expected to generate value following the expiration of all renewal periods under existing leases. The useful lives of intangible assets are estimated based on the period over which the intangible asset is expected to benefit the Company and gives consideration to the expected useful life of other assets to which the useful life may relate. Amortization expense for intangible assets is computed using the straight-line method over the estimated useful life of each of the intangible assets. The useful life of the site rental contracts and tenant relationships intangible asset is limited by the maximum depreciable life of the communications infrastructure ( 20 years), as a result of the interdependency of the communications infrastructure and site rental leases. In contrast, the site rental contracts and tenant relationships are estimated to provide economic benefits for several decades because of the low rate of tenant cancellations and high rate of renewals experienced to date. Thus, while site rental contracts and tenant relationships are valued based upon the fair value, which includes assumptions regarding both (1) tenants' exercise of optional renewals contained in the acquired leases and (2) renewals of the acquired leases past the contractual term including exercisable options, the site rental contracts and tenant relationships are amortized over a period not to exceed 20 years as a result of the useful life being limited by the depreciable life of the communications infrastructure. The carrying value of other intangible assets with finite useful lives will be reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. The Company has a dual grouping policy for purposes of determining the unit of account for testing impairment of the site rental contracts and tenant relationships intangible assets. First, the Company pools the site rental contracts and tenant relationships with the related communications infrastructure assets into portfolio groups for purposes of determining the unit of account for impairment testing. Second and separately, the Company evaluates the site rental contracts and tenant relationships by significant tenant or by tenant grouping for individually insignificant tenants, as appropriate. If the sum of the estimated future cash flows (undiscounted) expected to result from the use or eventual disposition of an asset is less than the carrying amount of the asset, an impairment loss is recognized. Measurement of an impairment loss is based on the fair value of the asset.
Deferred Credits	Deferred Credits Deferred credits are included in "deferred revenues" and "other long-term liabilities" on the Company's consolidated balance sheet and consist of the estimated fair value of the following items recorded in conjunction with acquisitions: (1) below-market tenant leases for contractual interests with tenants on acquired communications infrastructure, which are amortized to site rental revenues and (2) above-market leases for land interests under the Company's communications infrastructure, which are amortized to site rental cost of operations. Fair value for these deferred credits represents the difference between (1) the stated contractual payments to be made pursuant to the in-place lease and (2) management's estimate of fair market lease rates for each corresponding lease. Deferred credits are measured over a period equal to the estimated remaining economic lease term considering renewal provisions or economics associated with those renewal provisions, to the extent applicable. Deferred credits are amortized over their respected estimated lease terms at the time of acquisition.
Deferred Financing Costs	Deferred Financing Costs Third-party costs incurred to obtain financing, with the exception of costs incurred related to revolving lines of credit, are deferred and are included as a direct deduction from the carrying amount of the related debt liability in "debt and other long-term obligations" on the Company's consolidated balance sheet. Third party costs incurred to obtain financing through a revolving line of credit are deferred and are included in "long-term prepaid rent and other assets, net" on the Company's consolidated balance sheet.
Revenue Recognition	Revenue Recognition The Company generates site rental revenues from its core business by providing tenants with access, including space or capacity, to its shared communications infrastructure via long-term contracts in various forms, including lease, license, sublease and service agreements. Providing such access over the length of the contract term represents the Company’s sole performance obligation under its site rental contracts. Site rental revenues. Site rental revenues from the Company's contracts are recognized on a straight-line, ratable basis over the fixed, non-cancelable term of the relevant contract, which generally ranges from five to 15 years for wireless tenants and three to 20 years related to the Company's fiber solutions tenants (including from organizations with high-bandwidth and multi-location demands), regardless of whether the payments from the tenant are received in equal monthly amounts during the life of the contract. Certain of the Company's contracts contain fixed escalation clauses (such as fixed dollar or fixed percentage increases) or inflation-based escalation clauses (such as those tied to the consumer price index ("CPI")). If the payment terms call for fixed escalations, upfront payments, or rent free periods, the revenue is recognized on a straight-line basis over the fixed, non-cancelable term of the agreement. When calculating straight-line rental revenues, the Company considers all fixed elements of tenant contractual escalation provisions, even if such escalation provisions contain a variable element in addition to a minimum. The Company's assets related to straight-line site rental revenues include current amounts of $92 million and $86 million included in "other current assets" and non-current amounts of $1.4 billion and $1.3 billion included in "deferred site rental receivables" for the years ended December 31, 2018 and 2017 , respectively. Amounts billed or received prior to being earned are deferred and reflected in "deferred revenues" and "other long-term liabilities." Amounts to which the Company has an unconditional right to payment, which are related to both satisfied or partially satisfied performance obligations, are recorded within "receivables, net" on the Company's consolidated balance sheet. Services and other revenues. As part of the Company’s effort to provide comprehensive communications infrastructure solutions, the Company offers certain services, primarily relating to its towers and small cells, predominately consisting of (1) site development services and (2) installation services. Upon contract commencement, the Company assesses its services to tenants and identifies performance obligations for each promise to provide a distinct service. The Company may have multiple performance obligations for site development services, which primarily include: structural analysis, zoning, permitting and construction drawings. For each of the above performance obligations, services revenues are recognized at completion of the applicable performance obligation, which represents the point at which the Company believes it has transferred goods or services to the tenant. The revenue recognized is based on an allocation of the transaction price among the performance obligations in a respective contract based on estimated standalone selling price. The volume and mix of site development services may vary among contracts and may include a combination of some or all of the above performance obligations. Payments generally are due within 45 to 60 days and generally do not contain variable-consideration provisions. The Company has one performance obligation for installation services, which is satisfied at the time of the respective installation or augmentation. Since performance obligations are typically satisfied prior to receiving payment from tenants, the unconditional right to payment is recorded within "receivables, net" on the Company’s consolidated balance sheet. The vast majority of the Company’s services relates to the Company’s Towers segment, and generally have a duration of one year or less. Additional information on revenues. As of January 1, 2018 and December 31, 2018, $2.1 billion and $2.3 billion of unrecognized revenue, respectively, was reported in "deferred revenues" and "other non-current liabilities" on our consolidated balance sheet. During the year ended December 31, 2018 , approximately $400 million of the January 1, 2018 unrecognized revenue balance was recognized as revenue. See also " Recently Adopted Accounting Pronouncements " below for further discussion.
Cost of Operations	Costs of Operations Approximately half of the Company's site rental costs of operations expenses consist of Towers ground lease expenses, and the remainder includes fiber access expenses, property taxes, repairs and maintenance expenses, employee compensation or related benefit costs, or utilities. Generally, the ground leases for land are specific to each site and are for an initial term of five years and are renewable for pre-determined periods. The Company also enters into term easements and ground leases in which it prepays the entire term in advance. Fiber access expenses primarily consist of leases of fiber assets and other access agreements to facilitate the Company's communications infrastructure. Ground lease and fiber access expenses are recognized on a ratable basis, regardless of whether the payment terms require the Company to make payments annually, quarterly, monthly, or for the entire term in advance. Certain of the Company's ground lease and fiber access agreements contain fixed escalation clauses (such as fixed dollar or fixed percentage increases) or inflation-based escalation clauses (such as those tied to the CPI). If the payment terms include fixed escalation provisions, the effect of such increases is recognized on a straight-line basis. The Company calculates the straight-line expense using a time period that equals or exceeds the remaining depreciable life of the communications infrastructure asset. Further, when a tenant has exercisable renewal options that would compel the Company to exercise existing renewal options, the Company has straight-lined the expense over a sufficient portion of such renewals to coincide with the final termination of the tenant's renewal options. The Company's non-current liability related to straight-line expense is included in "other long-term liabilities" on the Company's consolidated balance sheet. The Company's assets related to prepaid agreements is included in "prepaid expenses" and "long-term prepaid rent and other assets, net" on the Company's consolidated balance sheet. Services and other costs of operations predominately consist of third-party service providers such as contractors and professional services firms and, to a lesser extent, internal labor costs.
Acquisition and Integration Costs	Acquisition and Integration Costs Direct or incremental costs related to a business combination transaction are expensed as incurred. Such costs are predominately comprised of severance, retention bonuses payable to employees of an acquired enterprise, temporary employees to assist with the integration of the acquired operations, fees paid for services (such as consulting, accounting, legal, or engineering reviews), and any other costs directly associated with the transaction. These business combination costs are included in "acquisition and integration costs" on the Company's consolidated statement of operations and comprehensive income (loss). For those transactions accounted for as asset acquisitions, these costs are capitalized as part of the purchase price. See note 3 for a discussion of the Company's recent acquisitions.
Stock-Based Compensation	Stock-Based Compensation Restricted Stock Units. The Company records stock-based compensation expense only for those unvested restricted stock units ("RSUs") for which the requisite service is expected to be rendered. The cumulative effect of a change in the estimated number of RSUs for which the requisite service is expected to be or has been rendered is recognized in the period of the change in the estimate. To the extent that the requisite service is rendered, compensation cost for accounting purposes is not reversed; rather, it is recognized regardless of whether or not the awards vest. A discussion of the Company's valuation techniques and related assumptions and estimates used to measure the Company's stock-based compensation is as follows: Valuation. The fair value of RSUs without market conditions is determined based on the number of shares relating to such RSUs and the quoted price of the Company's common stock at the date of grant. The Company estimates the fair value of RSUs with market conditions granted using a Monte Carlo simulation. The Company's determination of the fair value of RSUs with market conditions on the date of grant is affected by its common stock price as well as assumptions regarding a number of highly complex or subjective variables. The determination of fair value using a Monte Carlo simulation requires the input of subjective assumptions, and other reasonable assumptions could provide differing results. Amortization Method. The Company amortizes the fair value of all RSUs on a straight-line basis for each separately vesting tranche of the award (graded vesting schedule) over the requisite service periods. Expected Volatility. The Company estimates the volatility of its common stock at the date of grant based on the historical volatility of its common stock. Expected Dividend Rate. The expected dividend rate at the date of grant is based on the then-current dividend yield. Risk-Free Rate. The Company bases the risk-free rate on the implied yield currently available on U.S. Treasury issues with an equivalent remaining term equal to the expected life of the award. Forfeitures. The Company uses historical data and management's judgment about the future employee turnover rates to estimate the number of shares for which the requisite service period will not be rendered.
Interest Expense and Amortization of Deferred Financing Costs	Interest Expense and Amortization of Deferred Financing Costs The components of interest expense and amortization of deferred financing costs are as follows: Years Ended December 31, 2018 2017 2016 Interest expense on debt obligations $ 635 $ 582 $ 501 Amortization of deferred financing costs and adjustments on long-term debt, net 21 19 19 Capitalized interest (15 ) (12 ) (7 ) Other 1 2 2 Total $ 642 $ 591 $ 515 The Company amortizes deferred financing costs, discounts, premiums, and purchase price adjustments on long-term debt over the estimated term of the related borrowing using the effective interest yield method. Deferred financing costs, discounts or purchase price adjustments are generally presented as a direct reduction to the related debt obligation on the Company's consolidated balance sheet.
Income Taxes	Income Taxes The Company operates as a REIT for U.S. federal income tax purposes. As a REIT, the Company is generally entitled to a deduction for dividends that it pays and therefore is not subject to U.S. federal corporate income tax on its taxable income that is currently distributed to its stockholders. The Company also may be subject to certain federal, state, local, and foreign taxes on its income and assets, including (1) taxes on any undistributed income, (2) taxes related to the TRSs, (3) franchise taxes, (4) property taxes, and (5) transfer taxes. In addition, the Company could in certain circumstances be required to pay an excise or penalty tax, which could be significant in amount, in order to utilize one or more relief provisions under the Internal Revenue Code of 1986, as amended ("Code"), to maintain qualification for taxation as a REIT. Additionally, the Company has included in TRSs certain other assets and operations. Those TRS assets and operations will continue to be subject, as applicable, to federal and state corporate income taxes or to foreign taxes in the jurisdictions in which such assets and operations are located. The Company's foreign assets and operations (including its tower operations in Puerto Rico) are subject to foreign income taxes in the jurisdictions in which such assets and operations are located, regardless of whether they are included in a TRS or not. For its REIT conversion and certain subsequent acquisitions into the REIT, the Company will be subject to a federal corporate level tax rate (currently 21%) on any gain recognized from the sale of assets occurring within a specified period (generally 5 years) after the transfer date up to the amount of the built in gain that existed on the transfer date, which is based upon the fair market value of those assets in excess of the Company's tax basis on the transfer date. This gain can be offset by any remaining federal net operating loss carryforwards ("NOLs"). For the Company's TRSs, the Company accounts for income taxes using an asset and liability approach, which requires the recognition of deferred income tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company's financial statements or tax returns. Deferred income tax assets and liabilities are determined based on the temporary differences between the financial statement and tax bases of assets and liabilities using enacted tax rates. A valuation allowance is provided on deferred tax assets if it is determined that it is "more likely than not" that the asset will not be realized. The Company records a valuation allowance against deferred tax assets when it is "more likely than not" that some portion or all of the deferred tax asset will not be realized. The Company reviews the recoverability of deferred tax assets each quarter and based upon projections of future taxable income, reversing deferred tax liabilities or other known events that are expected to affect future taxable income, records a valuation allowance for assets that do not meet the "more likely than not" realization threshold. Valuation allowances may be reversed if related deferred tax assets are deemed realizable based upon changes in facts and circumstances that impact the recoverability of the asset. The Company recognizes a tax position if it is "more likely than not" that it will be sustained upon examination. The tax position is measured at the largest amount that is greater than 50 percent likely of being realized upon ultimate settlement. The Company reports penalties and tax-related interest expense as a component of the benefit (provision) for income taxes. As of December 31, 2018 and 2017 , the Company has not recorded any material penalties related to its income tax positions. See note 10 .
Per Share Information	Per Share Information Basic net income (loss) attributable to CCIC common stockholders, per common share excludes dilution and is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period. For the years ended December 31, 2018 and 2017 diluted net income (loss) attributable to CCIC common stockholders, per common share is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period plus any potential dilutive common share equivalents, including shares issuable upon (1) the vesting of RSUs as determined under the treasury stock method and (2) conversion of the Company's 6.875% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share ("6.875% Convertible Preferred Stock"), as determined under the if-converted method. For the year ended December 31, 2016 , diluted income (loss) attributable to CCIC common stockholders, per common share is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period plus any potential dilutive common share equivalents, including shares issuable upon (1) the vesting of RSUs as determined under the treasury stock method and (2) conversion of the Company's then outstanding 4.50% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share ("4.50% Convertible Preferred Stock"), as determined under the if-converted method. A reconciliation of the numerators and denominators of the basic and diluted per share computations is as follows: Years Ended December 31, 2018 2017 2016 Net income (loss) attributable to CCIC stockholders $ 671 $ 445 $ 357 Dividends on preferred stock (113 ) (58 ) (33 ) Net income (loss) attributable to CCIC common stockholders for basic and diluted computations $ 558 $ 387 $ 324 Weighted-average number of common shares outstanding (in millions): Basic weighted-average number of common stock outstanding 413 382 340 Effect of assumed dilution from potential issuance of common shares relating to RSUs 2 1 1 Diluted weighted-average number of common shares outstanding 415 383 341 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 1.35 $ 1.01 $ 0.95 Diluted $ 1.34 $ 1.01 $ 0.95 Dividends/distributions declared per share of common stock $ 4.28 $ 3.90 $ 3.61 For each of the years ended December 31, 2018 and 2017 , 15 million common share equivalents related to the 6.875% Convertible Preferred Stock were excluded from the dilutive common shares because the impact of the conversion of such preferred stock would be anti-dilutive based on the Company's common stock price at the end of each respective year. See notes 11 and 12 .
Fair Values	Fair Values The Company's assets and liabilities recorded at fair value are categorized based upon a fair value hierarchy that ranks the quality and reliability of the information used to determine fair value. The three levels of the fair value hierarchy are (1) Level 1 — quoted prices (unadjusted) in active and accessible markets, (2) Level 2 — observable prices that are based on inputs not quoted in active markets but corroborated by market data, and (3) Level 3 — unobservable inputs and are not corroborated by market data. The Company evaluates fair value hierarchy level classifications quarterly, and transfers between levels are effective at the end of the quarterly period. The fair value of cash and cash equivalents and restricted cash approximate the carrying value. The Company determines the fair value of its debt securities based on indicative quotes (that is non-binding quotes) from brokers that require judgment to interpret market information including implied credit spreads for similar borrowings on recent trades or bid/ask prices or quotes from active markets if applicable. Foreign currency swaps are valued at settlement amounts using observable exchange rates and, if material, reflect an adjustment for the Company's and contract counterparty's credit risk. There were no changes since December 31, 2017 in the Company's valuation techniques used to measure fair values. See note 9 for a further discussion of fair values.
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements In May 2014, the FASB released updated guidance regarding the recognition of revenue from contracts with customers not otherwise addressed by specific guidance (commonly referred to as "ASC 606" or "the revenue recognition standard"). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (1) identify the contracts with the customer; (2) identify the performance obligations in the contract; (3) determine the contract price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. This guidance was effective for the Company on January 1, 2018. This guidance was required to be applied, at the Company's election, either (1) retrospectively to each prior reporting period presented or (2) under the modified retrospective method, with the cumulative effect being recognized at the date of initial application. Given the nature of the Company’s contracts with tenants, the Company’s pattern of revenue recognition was not impacted by the adoption of the revenue recognition standard. The Company adopted the revenue recognition standard under the modified retrospective method, and the Company's adoption of the revenue recognition standard did not result in any adjustment to the balance of dividends/distributions in excess of earnings as of January 1, 2018. See " Revenue Recognition " above and note 4 for further discussion regarding the Company’s revenues. In November 2016, the FASB issued new guidance which requires an entity's statement of cash flows to explain the change in restricted cash and restricted cash equivalents in addition to the change in cash and cash equivalents. This new guidance also requires an entity that includes cash, cash equivalents, restricted cash and restricted cash equivalents on multiple lines on its balance sheet to present a reconciliation of those line items between its statement of cash flows and its balance sheet. The Company adopted this guidance retrospectively, on January 1, 2018, and the impact of the new guidance is limited to certain changes in presentation on the consolidated statement of cash flows and certain disclosures. See note 16 . In January 2017, the FASB issued new guidance which clarifies the definition of a business in order to assist companies in evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. The Company adopted the guidance on January 1, 2018, and the adoption of this guidance did not have a material impact on its consolidated financial statements. Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued new guidance on the recognition, measurement, presentation and disclosure of leases. The new guidance requires lessees to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments for all leases with a term greater than 12 months. The accounting for lessors remains largely unchanged from existing guidance. This guidance was effective for, and adopted by, the Company as of January 1, 2019, and was required to be adopted using a modified retrospective approach, which after certain additional updates in July 2018, allowed the Company to apply the new guidance either (1) as of the beginning of the earliest period presented, or (2) as of the effective date (i.e., January 1, 2019), without adjusting the comparative periods. The Company adopted the new guidance using a modified retrospective approach as of the effective date (i.e., January 1, 2019), without adjusting the comparative periods. The Company's adoption of the new guidance did not result in a cumulative-effect adjustment being recognized to the opening balance of retained earnings. The Company elected the package of practical expedients upon adoption and thus did not reassess the classification or lease term of leases existing prior to January 1, 2019. When its first quarter 2019 results are reported, the Company expects that (1) the vast majority of its lessor and lessee arrangements will continue to be classified as operating leases under the new guidance; (2) this guidance will result in a lease liability as of March 31, 2019 ranging between $5 billion and $7 billion (which primarily consist of ground leases under the Company's towers and fiber-related leases) and a corresponding right-of-use asset; and (3) there will not be a material impact to its consolidated statement of operations and consolidated statement of cash flows. The Company is in the process of updating certain of its existing information technology systems for both the Towers and Fiber segments to integrate the new lease guidance requirements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Components of Interest Expense and Amortization of Deferred Financing Costs	The components of interest expense and amortization of deferred financing costs are as follows: Years Ended December 31, 2018 2017 2016 Interest expense on debt obligations $ 635 $ 582 $ 501 Amortization of deferred financing costs and adjustments on long-term debt, net 21 19 19 Capitalized interest (15 ) (12 ) (7 ) Other 1 2 2 Total $ 642 $ 591 $ 515
Reconciliation of the Numerators and Denominators of the Basic and Diluted Per Share Computations	A reconciliation of the numerators and denominators of the basic and diluted per share computations is as follows: Years Ended December 31, 2018 2017 2016 Net income (loss) attributable to CCIC stockholders $ 671 $ 445 $ 357 Dividends on preferred stock (113 ) (58 ) (33 ) Net income (loss) attributable to CCIC common stockholders for basic and diluted computations $ 558 $ 387 $ 324 Weighted-average number of common shares outstanding (in millions): Basic weighted-average number of common stock outstanding 413 382 340 Effect of assumed dilution from potential issuance of common shares relating to RSUs 2 1 1 Diluted weighted-average number of common shares outstanding 415 383 341 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 1.35 $ 1.01 $ 0.95 Diluted $ 1.34 $ 1.01 $ 0.95 Dividends/distributions declared per share of common stock $ 4.28 $ 3.90 $ 3.61

Acquisitions Acquisitions (Tabl

Acquisitions Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2018
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information [Table Text Block]	The unaudited pro forma financial results for the years ended December 31, 2017 and 2016 combine the historical results of the Company, along with the historical results of the 2017 Acquisitions for the respective periods. The following table presents the unaudited pro forma consolidated results of operations of the Company as if each acquisition was completed as of January 1, 2016 for the periods presented below. The unaudited pro forma amounts are presented for illustrative purposes only and are not necessarily indicative of future consolidated results of operations. Twelve Months Ended December 31, 2017 2016 Net revenues $ 5,050 $ 4,865 Income (loss) before income taxes $ 541 (b)(c) $ 367 (b)(c)(d) Benefit (provision) for income taxes $ (29 ) (a) $ (21 ) (a) Net income (loss) $ 512 (b)(c) $ 346 (b)(c)(d) Basic net income (loss) attributable to CCIC common stockholders, per common share $ 0.89 (c)(e) $ 0.51 (c)(e) Diluted net income (loss) attributable to CCIC common stockholders, per common share $ 0.88 (c)(e) $ 0.51 (c)(e) (a) For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to the benefit (provision) for income tax as a result of the Company's REIT status. The vast majority of the assets and related income from the FiberNet Acquisition, the Wilcon Acquisition, and the Lightower Acquisition are included in the Company's REIT. The remaining assets are included in the Company's TRS. For purposes of the unaudited pro forma financial results, an adjustment has been made to reflect the additional tax impact of the income related to the TRS assets. (b) For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to depreciation and amortization of $247 million and $316 million , respectively, related to property and equipment and intangibles recorded as a result of the 2017 Acquisitions. (c) Pro forma amounts include the impact of the interest expense and common stock share issuances associated with the related debt and equity financings for the 2017 Acquisitions (see above and notes 8 and 11 ). (d) Amounts are inclusive of a total of $120 million of Lightower stock-based compensation expense and acquisition and integration costs. (e) Pro forma amounts include the impact of the preferred stock dividends related to the Mandatory Convertible Preferred Stock Offering (as defined in note 11 ) for the Lightower Acquisition (see above and note 11 ).
Lightower Acquisition [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The final purchase price allocation for the Lightower Acquisition is shown below. Final Purchase Price Allocation Current assets $ 99 Property and equipment 2,194 Goodwill (a) 3,171 Other intangible assets, net (b) 2,177 Other non-current assets 27 Current liabilities (176 ) Other non-current liabilities (342 ) Net assets acquired (c) $ 7,150 (a) The final purchase price allocation for the Lightower Acquisition resulted in the recognition of goodwill based on: • the Company's expectation to leverage the Lightower fiber footprint to support new small cells and fiber solutions , • the complementary nature of the Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments , • the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and • other intangibles not qualified for separate recognition, including the assembled workforce. (b) Predominantly comprised of site rental contracts and tenant relationships. (c) The vast majority of the assets have been included in the Company's REIT. As such, no deferred taxes were recorded in connection with the Lightower Acquisition
FiberNet Acquisition [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The final purchase price allocation for the FiberNet Acquisition is shown below. Final Purchase Price Allocation Current assets $ 52 Property and equipment 438 Goodwill (a) 778 Other intangible assets, net (b) 327 Other non-current assets 2 Current liabilities (41 ) Other non-current liabilities (35 ) Net assets acquired (c) $ 1,521 (a) The final purchase price allocation for the FiberNet Acquisition resulted in the recognition of goodwill based on: • the Company's expectation to leverage the FiberNet fiber footprint to support new small cells and fiber solutions, • the complementary nature of the FiberNet fiber to the Company's existing fiber assets and its location in top metro markets where the Company expects to see wireless carrier network investments, • the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and • other intangibles not qualified for separate recognition, including the assembled workforce. (b) Predominantly comprised of site rental contracts and tenant relationships. (c) The vast majority of the assets have been included in the Company's REIT. As such, no deferred taxes were recorded in connection with the FiberNet Acquisition.

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	The following table is a summary of the contracted amounts owed to the Company by tenants pursuant to site rental contracts in effect as of December 31, 2018. As of December 31, 2018 , the weighted-average remaining term of tenant contracts is approximately five years, exclusive of renewals at the tenant's option. Years ending December 31, 2019 2020 2021 2022 2023 Thereafter Total Contracted amounts $ 3,968 $ 3,761 $ 3,552 $ 3,317 $ 2,587 $ 6,229 $ 23,414

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Major Classes of Property and Equipment	The major classes of property and equipment are as follows: Estimated Useful Lives As of December 31, 2018 2017 Land (a) — $ 1,981 $ 1,859 Buildings 40 years 134 119 Communications infrastructure assets 1-20 years 18,709 17,184 Information technology assets and other 2-7 years 443 372 Construction in process — 975 899 Total gross property and equipment 22,242 20,433 Less: accumulated depreciation (8,566 ) (7,500 ) Total property and equipment, net $ 13,676 $ 12,933 (a) Includes land owned in fee and perpetual easements.

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Finite-Lived Intangible Assets [Line Items]
Schedule of Goodwill	Goodwill The changes in the carrying value of goodwill for the years ended December 31, 2018 and December 31, 2017 were as follows: Balance as of December 31, 2016 $ 5,758 Additions due to FiberNet Acquisition (a) 778 Additions due to Wilcon Acquisition (a) 358 Additions due to Lightower Acquisition (a) 3,115 Adjustments due to other acquisitions, purchase price allocations and other, net 12 Balance as of December 31, 2017 $ 10,021 Adjustments due to other acquisitions, purchase price allocations and other, net 57 Balance as of December 31, 2018 $ 10,078 (a) The final purchase price allocations for the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition resulted in the recognition of goodwill in the Fiber segment based on: • the Company's expectation to leverage the FiberNet, Wilcon and Lightower fiber footprint to support new small cells and fiber solutions , • the complementary nature of the FiberNet, Wilcon and Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments , • the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and • other intangibles not qualified for separate recognition, including the assembled workforce. See note 3
Intangible Assets	The following is a summary of the Company's intangible assets. See note 3 for further discussion of the Company's acquisitions. As of December 31, 2018 As of December 31, 2017 Gross Carrying Value (a) Accumulated Amortization Net Book Value Gross Carrying Value Accumulated Amortization Net Book Value Site rental contracts and tenant relationships $ 7,787 $ (2,578 ) $ 5,209 $ 7,782 $ (2,156 ) $ 5,626 Other intangible assets 494 (187 ) 307 504 (168 ) 336 Total $ 8,281 $ (2,765 ) $ 5,516 $ 8,286 $ (2,324 ) $ 5,962 (a) During the year ended December 31, 2018 , intangible assets additions (primarily site rental contracts and tenant relationships) from acquisitions had a weighted average amortization period of approximately 20 years.
Schedule of Amortization Expense	Amortization expense related to intangible assets is classified as follows on the Company's consolidated statement of operations and comprehensive income (loss): For Years Ended December 31, Classification 2018 2017 2016 Depreciation, amortization and accretion $ 428 $ 314 $ 265 Site rental costs of operations 17 18 19 Total amortization expense $ 445 $ 332 $ 284
Site Rental Contracts and Customer Relationships [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Schedule of Estimated Annual Amortization Expense	The estimated annual amortization expense related to intangible assets (inclusive of those recorded as an increase to "site rental costs of operations") for the years ending December 31, 2019 to 2023 is as follows: Years Ending December 31, 2019 2020 2021 2022 2023 Estimated annual amortization $ 445 $ 444 $ 444 $ 443 $ 443

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Other Liabilities [Abstract]
Other Noncurrent Liabilities	The following is a summary of the components of "other long-term liabilities" as presented on the Company's consolidated balance sheet. See also note 2 . December 31, 2018 2017 Deferred rental revenues $ 1,267 $ 1,077 Deferred ground lease payable 603 560 Above market leases for land interests, net 181 202 Deferred credits, net 499 532 Asset retirement obligation 192 174 Deferred income tax liabilities 7 5 Other long-term liabilities 10 4 Total $ 2,759 $ 2,554
Schedule of Above Market Leases	The estimated amortization expense related to above-market leases for land interests under the Company's towers recorded to site rental costs of operations for the years ending December 31, 2019 to 2023 is as follows: Years Ending December 31, 2019 2020 2021 2022 2023 Above-market leases for land interests $ 17 $ 16 $ 15 $ 14 $ 13
Amortization of below-market tenant leases	The following table summarizes the estimated annual amounts related to below-market tenant leases expected to be amortized into site rental revenues for the years ending December 31, 2019 to 2023 are as follows: Years Ending December 31, 2019 2020 2021 2022 2023 Below-market tenant leases $ 62 $ 55 $ 52 $ 47 $ 43

Debt and Other Obligations (Tab

Debt and Other Obligations (Tables)	12 Months Ended
	Dec. 31, 2018
Debt and Other Obligations [Abstract]
Schedule of Long-Term Debt Instruments	The table below sets forth the Company's debt and other obligations as of December 31, 2018 . Original Issue Date Contractual Maturity Date Outstanding Balance as of December 31, Stated Interest Rate as of December 31, 2018 2017 2018 (a) Tower Revenue Notes, Series 2010-3 Jan. 2010 Jan. 2040 (b)(c) — 1,246 N/A Tower Revenue Notes, Series 2010-6 Aug. 2010 Aug. 2040 (b)(c) — 995 N/A Tower Revenue Notes, Series 2015-1 May 2015 May 2042 (b)(c) 298 297 3.2 % Tower Revenue Notes, Series 2015-2 May 2015 May 2045 (b)(c) 693 692 3.7 % Tower Revenue Notes, Series 2018-1 July 2018 July 2043 (b)(c) 247 — 3.7 % Tower Revenue Notes, Series 2018-2 July 2018 July 2048 (b)(c) 742 — 4.2 % 3.849% Secured Notes Dec. 2012 Apr. 2023 994 993 3.9 % Secured Notes, Series 2009-1, Class A-1 Jul. 2009 Aug. 2019 (d) 12 32 6.3 % Secured Notes, Series 2009-1, Class A-2 Jul. 2009 Aug. 2029 (d) 70 70 9.0 % Capital leases and other obligations Various Various (e) 227 227 Various Total secured debt $ 3,283 $ 4,552 2016 Revolver Jan. 2016 June 2023 1,075 (f) 980 3.8 % (g) 2016 Term Loan A Jan. 2016 June 2023 2,354 2,397 3.8 % (g) 5.250% Senior Notes Oct. 2012 Jan. 2023 1,641 1,639 5.3 % 4.875% Senior Notes Apr. 2014 Apr. 2022 844 842 4.9 % 3.400% Senior Notes Feb./May 2016 Feb. 2021 850 850 3.4 % 4.450% Senior Notes Feb. 2016 Feb. 2026 892 891 4.5 % 3.700% Senior Notes May 2016 June 2026 744 743 3.7 % 2.250% Senior Notes Sept. 2016 Sept. 2021 697 695 2.3 % 4.000% Senior Notes Feb. 2017 Mar. 2027 494 494 4.0 % 4.750% Senior Notes May 2017 May 2047 343 343 4.8 % 3.200% Senior Notes Aug. 2017 Sept. 2024 743 742 3.2 % 3.650% Senior Notes Aug. 2017 Sept. 2027 992 991 3.7 % 3.150% Senior Notes Jan. 2018 July 2023 742 — 3.2 % 3.800% Senior Notes Jan. 2018 Feb. 2028 988 — 3.8 % Total unsecured debt $ 13,399 $ 11,607 Total debt and other obligations 16,682 16,159 Less: current maturities and short-term debt and other current obligations 107 115 Non-current portion of long-term debt and other long-term obligations $ 16,575 $ 16,044 (a) Represents the weighted-average stated interest rate. (b) The Tower Revenue Notes, Series 2010-3 ("January 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2010-6 ("August 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2015-1 and 2015-2 ("May 2015 Tower Revenue Notes") and Tower Revenue Notes, Series 2018-1 and 2018-2 ("July 2018 Tower Revenue Notes") are collectively referred to herein as "Tower Revenue Notes." (c) If the respective series of Tower Revenue Notes are not paid in full on or prior to an applicable anticipated repayment date, then Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes, and additional interest (of an additional approximately 5% per annum) will accrue on the respective Tower Revenue Notes. As of December 31, 2018, the Tower Revenue Notes have principal amounts of $300 million , $250 million , $700 million and $750 million , with anticipated repayment dates in 2022, 2023, 2025 and 2028, respectively. (d) The Secured Notes, Series 2009-1, Class A-1 and Secured Notes, Series 2009-1, Class A-2 are collectively referred to herein as "2009 Securitized Notes." (e) The Company's capital leases and other obligations relate to land, fiber, vehicles, and other assets and bear interest rates ranging up to 10% and mature in periods ranging from less than one year to approximately 30 years . (f) As of December 31, 2018 , the undrawn availability under the 2016 Revolver was $3.2 billion . See note 18 . (g) The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.000% to 1.750% , based on the Company's senior unsecured debt rating. The Company pays a commitment fee ranging from 0.125% to 0.350% , based on the Company's senior unsecured debt rating, per annum on the undrawn available amount under the 2016 Revolver.
Schedule of Maturities of Long-term Debt	Contractual Maturities The following are the scheduled contractual maturities of the total debt or other long-term obligations outstanding at December 31, 2018 . These maturities reflect contractual maturity dates and do not consider the principal payments that will commence following the anticipated repayment dates on the Tower Revenue Notes. If the Tower Revenue Notes are not paid in full on or prior to their respective anticipated repayment dates, as applicable, then the Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes and additional interest (of an additional approximately 5% per annum) will accrue on the Tower Revenue Notes. Years Ending December 31, 2019 2020 2021 2022 2023 Thereafter Total Cash Obligations Unamortized Adjustments, Net Total Debt and Other Obligations Outstanding Scheduled contractual maturities $ 107 $ 142 $ 1,702 $ 1,087 $ 6,363 $ 7,390 $ 16,791 $ (109 ) $ 16,682
Schedule of Extinguishment of Debt	The following is a summary of the purchases and redemptions of debt during the years ended December 31, 2018 , 2017 and 2016 . Year Ending December 31, 2018 Principal Amount Cash Paid (a) Gains (losses) (b) Tower Revenue Notes, Series 2010-3 $ 1,250 $ 1,318 $ (71 ) 2016 Term Loan A — — (3 ) Tower Revenues Notes, Series 2010-6 1,000 1,028 (32 ) Total $ 2,250 $ 2,346 $ (106 ) (a) Exclusive of accrued interest. (b) Inclusive of the write off of the respective deferred financing costs. Year Ending December 31, 2017 Principal Amount Cash Paid Gains (losses) (a) 2016 Term Loan A $ — $ — $ (4 ) Total $ — $ — $ (4 ) (a) The losses related to write off of deferred financing costs. Year Ending December 31, 2016 Principal Amount Cash Paid (a) Gains (losses) (b) Revolving Credit Facility under 2012 Credit Facility $ — $ — $ (2 ) Tranche A Term Loans under 2012 Credit Facility 629 629 (2 ) Tranche B Term Loans under 2012 Credit Facility 2,247 2,247 (27 ) Tower Revenue Notes, Series 2010-2 350 353 (3 ) Tower Revenue Notes, Series 2010-5 300 307 (8 ) 2.381% Secured Notes 500 509 (10 ) Total $ 4,026 $ 4,045 $ (52 ) (a) Exclusive of accrued interest. (b) Inclusive of the write off of the respective deferred financing costs.

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Estimated Fair Values and Carrying Amounts of Assets and Liabilities	The following table shows the estimated fair values of the Company's financial instruments, along with the carrying amounts of the related assets (liabilities). See also note 2 . Level in Fair Value Hierarchy December 31, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Assets: Cash and cash equivalents 1 $ 277 $ 277 $ 314 $ 314 Restricted cash 1 136 136 126 126 Liabilities: Debt and other obligations 2 $ 16,682 $ 16,562 $ 16,159 $ 16,644

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income (Loss) from Continuing Operations Before Income Taxes	Income (loss) from continuing operations before income taxes by geographic area is as follows: Years Ended December 31, 2018 2017 2016 Domestic $ 667 $ 451 $ 349 Foreign (a) 23 20 25 Total $ 690 $ 471 $ 374 (a) Inclusive of income (loss) before income taxes from Puerto Rico.
Benefit (Provision) for Income Taxes	The benefit (provision) for income taxes consists of the following: Years Ended December 31, 2018 2017 2016 Current: Federal $ (5 ) $ (3 ) $ — Foreign (7 ) (6 ) (7 ) State (5 ) (2 ) (1 ) Total current (17 ) (11 ) (8 ) Deferred: Federal — (18 ) (8 ) Foreign (2 ) 3 (1 ) Total deferred (2 ) (15 ) (9 ) Total tax benefit (provision) $ (19 ) $ (26 ) $ (17 )
Effective Tax Rate	A reconciliation between the benefit (provision) for income taxes and the amount computed by applying the federal statutory income tax rate to the income (loss) before income taxes is as follows: Years Ended December 31, 2018 2017 2016 Benefit (provision) for income taxes at statutory rate $ (145 ) $ (165 ) $ (131 ) Tax effect of foreign income (losses) 1 — 1 Tax adjustment related to REIT operations 138 159 121 State tax (provision) benefit, net of federal (4 ) (2 ) (1 ) Foreign tax (9 ) (3 ) (7 ) Effects of tax law change (a) — (15 ) — Total $ (19 ) $ (26 ) $ (17 ) (a) Pursuant to the Tax Cuts and Jobs Act, which was signed into law in December 2017, the Company was required to write down its net federal deferred tax asset in the amount of $17 million as a result of the reduction in the federal corporate tax rate offset by a benefit of $2 million related to the refund of the Company's alternative minimum tax credit carryforward.
Components of Deferred Tax Assets and Liabilities	The components of the net deferred income tax assets and liabilities are as follows: December 31, 2018 2017 Deferred income tax liabilities: Property and equipment $ 5 $ 5 Deferred site rental receivable 7 7 Total deferred income tax liabilities 12 12 Deferred income tax assets: Intangible assets 4 5 Net operating loss carryforwards (a) 18 21 Deferred ground lease payable 2 2 Accrued liabilities 5 5 Other 3 1 Valuation allowances (1 ) (1 ) Total deferred income tax assets, net 31 33 Net deferred income tax asset (liabilities) $ 19 $ 21 (a) Balance results from the Company's foreign NOLs. Due to the Company's REIT status, no federal or state NOLs result in the Company recording a deferred income tax asset. See further discussion surrounding the Company's NOL balances below.
Jurisdictional Components of Deferred Tax Assets and Liabilities	The components of the net deferred income tax assets (liabilities) are as follows: December 31, 2018 December 31, 2017 Classification Gross Valuation Allowance Net Gross Valuation Allowance Net Federal $ 25 $ — $ 25 $ 25 $ — $ 25 State 1 — 1 1 — 1 Foreign (6 ) (1 ) (7 ) (4 ) (1 ) (5 ) Total $ 20 $ (1 ) $ 19 $ 22 $ (1 ) $ 21

Stockholders' Equity Stockholde

Stockholders' Equity Stockholders Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Dividends Declared [Abstract]
Dividends Declared	During the year ended December 31, 2018 , the following dividends were declared or paid: Equity Type Declaration Date Record Date Payment Date Dividends Per Share Aggregate Payment Amount (In millions) Common Stock February 21, 2018 March 16, 2018 March 30, 2018 $ 1.05 $ 439 (a) Common Stock May 17, 2018 June 15, 2018 June 29, 2018 $ 1.05 $ 438 (a) Common Stock August 2, 2018 September 14, 2018 September 28, 2018 $ 1.05 $ 438 (a) Common Stock October 15, 2018 December 14, 2018 December 31, 2018 $ 1.125 $ 467 (a) 6.875% Convertible Preferred Stock December 15, 2017 January 15, 2018 February 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock March 19, 2018 April 15, 2018 May 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock June 22, 2018 July 15, 2018 August 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock September 19, 2018 October 15, 2018 November 1, 2018 $ 17.1875 $ 28 6.875% Convertible Preferred Stock December 11, 2018 January 15, 2019 February 1, 2019 $ 17.1875 $ 28 (a) Inclusive of dividends accrued for holders of unvested RSUs, which will be paid when and if the RSUs vest.
Tax Treatment of Dividends Paid [Table Text Block]	The following table summarizes, for income tax purposes, the nature of dividends paid during 2018 on the Company's common stock and 6.875% Convertible Preferred Stock. Equity Type Payment Date Cash Distribution (per share) Ordinary Taxable Dividend (per share) Qualified Taxable Dividend (per share) (a) Section 199A Dividend (per share) Non-Taxable Distribution (per share) Common Stock March 30, 2018 $ 1.05 $ 0.689 $ 0.005 $ 0.684 $ 0.361 Common Stock June 29, 2018 $ 1.05 $ 0.689 $ 0.005 $ 0.684 $ 0.361 Common Stock September 28, 2018 $ 1.05 $ 0.689 $ 0.005 $ 0.684 $ 0.361 Common Stock December 31, 2018 $ 1.125 $ 0.738 $ 0.005 $ 0.733 $ 0.387 6.875% Convertible Preferred Stock February 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — 6.875% Convertible Preferred Stock May 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — 6.875% Convertible Preferred Stock August 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — 6.875% Convertible Preferred Stock November 1, 2018 $ 17.1875 $ 17.1875 $ 0.1269 $ 17.0606 $ — (a) Qualified taxable dividend and section 199A dividend amounts are included in ordinary taxable dividend amounts.

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Share-based Compensation [Abstract]
Summary of Restricted Stock Awards Activity	The following is a summary of the RSU activity during the year ended December 31, 2018 . RSUs (In millions) Outstanding at the beginning of year 3 Granted 1 Vested (1 ) Forfeited — Outstanding at end of year 3
Summary of the Assumptions Used in the Monte Carlo Simulation to Determine the Grant-Date Fair Value	The following table summarizes the assumptions used in the Monte Carlo simulation to determine the grant-date fair value for the awards granted during the years ended December 31, 2018 , 2017 and 2016 , respectively, with market conditions. Years Ended December 31, 2018 2017 2016 Risk-free rate 2.4 % 1.5 % 0.9 % Expected volatility 18 % 18 % 19 % Expected dividend rate 3.8 % 4.4 % 4.2 %
Summary of Restricted Stock Vested	The following table is a summary of the awards vested during the years ended December 31, 2018 , 2017 and 2016 . Years Ended December 31, Total Shares Vested Fair Value on Vesting Date (In millions of shares) 2018 1.0 $ 107 2017 0.7 67 2016 0.8 71
Stock Based Compensation Expense	The following table discloses the components of stock-based compensation expense. Years Ended December 31, 2018 2017 2016 Stock-based compensation expense: Site rental costs of operations $ 17 $ 15 $ 14 Services and other costs of operations 8 5 8 Selling, general and administrative expenses 83 76 75 Total stock-based compensation $ 108 $ 96 $ 97

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Tenant Leases	Tenant Leases See note 4 for further information regarding the contractual amounts (including tenant leases) owed to the Company pursuant to agreements in effect as of December 31, 2018.
Operating Leases	Operating Leases The following table is a summary of rental cash payments owed by the Company, as lessee, to landlords pursuant to contractual agreements in effect as of December 31, 2018 . The Company is obligated under non-cancelable operating leases for land interests under 74% of its towers. The majority of these lease agreements have (1) certain termination rights that provide for cancellation after a notice period, (2) multiple renewal options at the Company's option, and (3) annual escalations. Lease agreements may also contain provisions for a contingent payment based on revenues or the gross margin derived from the communications infrastructure located on the leased land interest. Approximately 90% of our Towers site rental gross margin and more than 75% of our Towers site rental gross margin is derived from towers that reside on land that we own or control for greater than 10 and 20 years, respectively. The operating lease payments included in the table below include payments for certain renewal periods at the Company's option that are reasonably assured to be exercised and an estimate of contingent payments based on revenues and gross margins derived from existing tenant leases. Years Ending December 31, 2019 2020 2021 2022 2023 Thereafter Total Operating leases $ 640 $ 631 $ 628 $ 623 $ 619 $ 8,054 $ 11,195

Operating Segments and Concen_2

Operating Segments and Concentrations of Credit Risk (Tables) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Segment Reporting Information [Line Items]
Segment Site Rental Revenues	$ 4,716		$ 3,669		$ 3,233
Allocated Share-based Compensation Expense	$ 108		$ 96		$ 97
Concentration Risk, Percentage	75.00%		86.00%		88.00%
Segment Services and Other Revenues	$ 707		$ 687		$ 688
Segment Revenues	5,423		4,356		3,921
Direct Costs of Leased and Rented Property or Equipment	1,373		1,109		987
Segment Services and Other Cost of Operations	429		415		410
Segment Cost of Operations	1,802	[1],[2]	1,524	[3],[4]	1,397	[5],[6]
Segment site rental gross margin	3,343		2,560		2,246
Segment General and Administrative Expenses	289	[2]	183	[4]	153	[6]
Segment Operating Profit	3,332		2,649		2,371
Depreciation, amortization and accretion	1,528		1,242		1,109
Interest expense and amortization of deferred financing costs	642		591		515
Other income (expenses) to reconcile to income (loss) before income taxes	173	[7]	82	[8]	133	[9]
Income (Loss) Before Income Taxes	690		471		374
Assets	32,785		32,229		22,675
Goodwill	$ 10,078		$ 10,021		$ 5,758
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Year Ended December 31, 2018 Towers Fiber Other Consolidated Total Segment site rental revenues $ 3,116 $ 1,600 $ 4,716 Segment services and other revenues 691 16 707 Segment revenues 3,807 1,616 5,423 Segment site rental cost of operations 848 525 1,373 Segment services and other cost of operations 418 11 429 Segment cost of operations (a)(b) 1,266 536 1,802 Segment site rental gross margin 2,268 1,075 3,343 Segment services and other gross margin 273 5 278 Segment selling, general and administrative expenses (b) 110 179 289 Segment operating profit (loss) 2,431 901 3,332 Other selling, general and administrative expenses (b) $ 191 191 Stock-based compensation expense 108 108 Depreciation, amortization and accretion 1,528 1,528 Interest expense and amortization of deferred financing costs 642 642 Other (income) expenses to reconcile to income (loss) before income taxes (c) 173 173 Income (loss) before income taxes $ 690 Capital expenditures $ 442 $ 1,264 $ 35 $ 1,741 Total assets (at year end) $ 17,667 $ 14,512 $ 606 $ 32,785 Total goodwill (at year end) $ 5,127 $ 4,951 $ — $ 10,078 (a) Exclusive of depreciation, amortization and accretion shown separately (b) Segment cost of operations for the year ended December 31, 2018 excludes (1) stock-based compensation expense of $25 million and (2) prepaid lease purchase price adjustments of $20 million For the year ended December 31, 2018 , Segment selling, general and administrative expenses exclude stock-based compensation expense of $83 million . (c) See consolidated statement of operations for further information.		Year Ended December 31, 2017 Towers Fiber Other Consolidated Total Segment site rental revenues $ 2,900 $ 769 $ 3,669 Segment services and other revenues 637 50 687 Segment revenues 3,537 819 4,356 Segment site rental cost of operations 845 264 1,109 Segment services and other cost of operations 374 41 415 Segment cost of operations (a)(b) 1,219 305 1,524 Segment site rental gross margin 2,055 505 2,560 Segment services and other gross margin 263 9 272 Segment selling, general and administrative expenses (b) 94 89 183 Segment operating profit (loss) 2,224 425 2,649 Other selling, general and administrative expenses (b) $ 167 167 Stock-based compensation expense 96 96 Depreciation, amortization and accretion 1,242 1,242 Interest expense and amortization of deferred financing costs 591 591 Other (income) expenses to reconcile to income (loss) before income taxes (c) 82 82 Income (loss) before income taxes $ 471 Capital expenditures $ 418 $ 782 $ 28 $ 1,228 Total assets (at year end) $ 17,941 $ 13,669 $ 619 $ 32,229 Total goodwill (at year end) $ 5,127 $ 4,894 $ — $ 10,021 (a) Exclusive of depreciation, amortization and accretion shown separately (b) Segment cost of operations for the year ended December 31, 2017 excludes (1) stock-based compensation expense of $20 million and (2) prepaid lease purchase price adjustments of $20 million . For the year ended December 31, 2017 . Segment selling, general and administrative expenses exclude stock-based compensation expense of $76 million . (c) See consolidated statement of operations for further information.		Year Ended December 31, 2016 Towers Fiber Other Consolidated Total Segment site rental revenues $ 2,831 $ 402 $ 3,233 Segment services and other revenues 604 84 688 Segment revenues 3,435 486 3,921 Segment site rental cost of operations 840 147 987 Segment services and other cost of operations 345 65 410 Segment cost of operations (a)(b) 1,185 212 1,397 Segment site rental gross margin 1,991 255 2,246 Segment services and other gross margin 259 19 278 Segment selling, general and administrative expenses (b) 93 60 153 Segment operating profit (loss) 2,157 214 2,371 Other selling, general and administrative expenses (b) $ 143 143 Stock-based compensation expense 97 97 Depreciation, amortization and accretion 1,109 1,109 Interest expense and amortization of deferred financing costs 515 515 Other (income) expenses to reconcile to income (loss) before income taxes (c) 133 133 Income (loss) before income taxes $ 374 Capital expenditures $ 430 $ 409 $ 35 $ 874 Total assets (at year end) $ 18,395 $ 3,441 $ 839 $ 22,675 Total goodwill (at year end) $ 5,115 $ 643 $ — $ 5,758 (a) Exclusive of depreciation, amortization and accretion shown separately (b) Segment cost of operations for the year ended December 31, 2016 excludes (1) stock-based compensation expense of $22 million and (2) prepaid lease purchase price adjustments of $22 million . For the year ended December 31, 2016 , Segment selling, general and administrative expenses exclude stock-based compensation expense of $75 million for the year ended . (c) See consolidated statement of operations for further information.
A Summary of the Percentage of the Consolidated Revenues for Those Customers Accounting for More than 10% of the Consolidated Revenues	The following table summarizes the percentage of the consolidated revenues for those tenants accounting for more than 10% of the consolidated revenues. Years Ended December 31, 2018 2017 2016 AT&T 20 % 25 % 27 % T-Mobile 20 % 22 % 23 % Verizon Wireless 20 % 22 % 22 % Sprint 15 % 17 % 16 % Total 75 % 86 % 88 %
Towers [Member]
Segment Reporting Information [Line Items]
Segment Site Rental Revenues	$ 3,116		$ 2,900		$ 2,831
Segment Services and Other Revenues	691		637		604
Segment Revenues	3,807		3,537		3,435
Direct Costs of Leased and Rented Property or Equipment	848		845		840
Segment Services and Other Cost of Operations	418		374		345
Segment Cost of Operations	1,266	[1],[2]	1,219	[3],[4]	1,185	[5],[6]
Segment site rental gross margin	2,268		2,055		1,991
Segment General and Administrative Expenses	110	[2]	94	[4]	93	[6]
Segment Operating Profit	2,431		2,224		2,157
Assets	17,667		17,941		18,395
Goodwill	5,127		5,127		5,115
Fiber [Member]
Segment Reporting Information [Line Items]
Segment Site Rental Revenues	1,600		769		402
Segment Services and Other Revenues	16		50		84
Segment Revenues	1,616		819		486
Direct Costs of Leased and Rented Property or Equipment	525		264		147
Segment Services and Other Cost of Operations	11		41		65
Segment Cost of Operations	536	[1],[2]	305	[3],[4]	212	[5],[6]
Segment site rental gross margin	1,075		505		255
Segment General and Administrative Expenses	179	[2]	89	[4]	60	[6]
Segment Operating Profit	901		425		214
Assets	14,512		13,669		3,441
Goodwill	4,951		4,894		643
Other [Member]
Segment Reporting Information [Line Items]
Allocated Share-based Compensation Expense	108		96		97
Segment General and Administrative Expenses	191	[2]	167	[4]	143	[6]
Segment Operating Profit
Depreciation, amortization and accretion	1,528		1,242		1,109
Interest expense and amortization of deferred financing costs	642		591		515
Other income (expenses) to reconcile to income (loss) before income taxes	173	[7]	82	[8]	133	[9]
Assets	606		619		839
Goodwill	$ 0		$ 0		$ 0
[1]	Exclusive of depreciation, amortization and accretion shown separately
[2]	Segment cost of operations for the year ended December 31, 2018 excludes (1) stock-based compensation expense of $25 million and (2) prepaid lease purchase price adjustments of $20 million For the year ended December 31, 2018, Segment selling, general and administrative expenses exclude stock-based compensation expense of $83 million.
[3]	Exclusive of depreciation, amortization and accretion shown separately
[4]	Segment cost of operations for the year ended December 31, 2017 excludes (1) stock-based compensation expense of $20 million and (2) prepaid lease purchase price adjustments of $20 million. For the year ended December 31, 2017. Segment selling, general and administrative expenses exclude stock-based compensation expense of $76 million.
[5]	Exclusive of depreciation, amortization and accretion shown separately
[6]	Segment cost of operations for the year ended December 31, 2016 excludes (1) stock-based compensation expense of $22 million and (2) prepaid lease purchase price adjustments of $22 million. For the year ended December 31, 2016, Segment selling, general and administrative expenses exclude stock-based compensation expense of $75 million for the year ended .
[7]	See consolidated statement of operations for further information.
[8]	See consolidated statement of operations for further information.
[9]	See consolidated statement of operations for further information.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash [Table Text Block]	As of December 31, 2018 2017 2016 Cash and cash equivalents $ 277 $ 314 $ 568 Restricted cash, current 131 121 125 Restricted cash reported within long-term prepaid rent and other assets, net 5 5 5 Cash, cash equivalents and restricted cash $ 413 $ 440 $ 698
Supplemental Disclosure of Cash Flow Information and Non-cash Investing and Financing Activities	The following table is a summary of the supplemental cash flow information during the years ended December 31, 2018 , 2017 and 2016 . Years Ended December 31, 2018 2017 2016 Supplemental disclosure of cash flow information: Interest paid $ 619 $ 547 $ 471 Income taxes paid 17 16 14 Supplemental disclosure of non-cash investing and financing activities: Increase in accounts payable for purchases of property and equipment 29 2 18 Purchase of property and equipment under capital leases and installment land purchases 40 32 52 Increase in preferred stock dividends accrued but not paid (see note 11) — 28 —

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information (Unaudited)	Summary quarterly financial information for the years ended December 31, 2018 and 2017 is as follows: Three Months Ended (a) March 31 June 30 September 30 December 31 2018: Net revenues $ 1,299 $ 1,330 $ 1,375 $ 1,419 Operating income (loss) 349 345 359 379 Gains (losses) on retirement of long-term obligations (71 ) (3 ) (32 ) — Benefit (provision) for income taxes (4 ) (5 ) (5 ) (5 ) Net income (loss) attributable to CCIC stockholders 86 152 136 185 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 0.21 $ 0.37 $ 0.33 $ 0.45 Diluted $ 0.21 $ 0.36 $ 0.33 $ 0.44 Three Months Ended (a) March 31 June 30 September 30 December 31 2017: Net revenues $ 1,016 $ 1,038 $ 1,063 $ 1,238 Operating income (loss) 257 259 261 267 Gains (losses) on retirement of long-term obligations (4 ) — — — Benefit (provision) for income taxes (4 ) (5 ) (2 ) (15 ) Net income (loss) attributable to CCIC stockholders 119 112 115 98 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 0.33 $ 0.31 $ 0.22 $ 0.17 Diluted $ 0.33 $ 0.31 $ 0.21 $ 0.17 (a) The sum of quarterly information may not agree to year to date information due to rounding.

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts Allowance for Doubtful Accounts (Tables)	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts Disclosure [Text Block]	Additions Deductions Balance at Beginning of Year Charged to Operations Credited to Operations Written Off Effect of Exchange Rate Changes Other Adjustments Balance at End of Year Allowance for Doubtful Accounts Receivable: 2018 $ 14 $ 4 $ — $ (4 ) $ — $ — $ 14 2017 $ 11 $ 4 $ — $ (5 ) $ — $ 4 (a) $ 14 2016 $ 10 $ 5 $ — $ (4 ) $ — $ — $ 11 (a) Represents the allowance for doubtful accounts reflected in the preliminary purchase price allocations for the 2017 Acquisitions. See note 3 . Additions Deductions Balance at Beginning of Year Charged to Operations Charged to Additional Paid-in Capital and Other Comprehensive Income Credited to Operations Credited to Additional Paid-in Capital and Other Comprehensive Income Other Adjustments (a) Balance at End of Year Deferred Tax Valuation Allowance: 2018 $ 1 $ — $ — $ — $ — $ — $ 1 2017 $ 7 $ — $ — $ (6 ) $ — $ — $ 1 2016 $ 2 $ 1 $ — $ (2 ) $ — $ 6 $ 7 (a) Inclusive of (1) the effects of acquisitions and (2) the inclusion of small cells in the REIT in January 2016.

Schedule III - Schedule of Re_2

Schedule III - Schedule of Real Estate and Depreciation Schedule of Real Estate and Accumulated Depreciation (Tables)	12 Months Ended
	Dec. 31, 2018
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 Disclosure [Text Block]	Description Encumbrances Initial Cost to Company Cost Capitalized Subsequent to Acquisition Gross Amount Carried at Close of Current Period Accumulated Depreciation at Close of Current Period Date of Construction Date Acquired Life on Which Depreciation in Latest Income Statement is Computed Communications infrastructure (1) $ 3,311 (2) (3) (3) $ 21,866 $ (8,341 ) Various Various Up to 20 years (1) Includes approximately 40,000 towers and 65,000 route miles of fiber. No single asset exceeds 5% of the aggregate gross amounts at which the assets were carried at the close of the period set forth in the table above. (2) 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). (3) The Company has omitted this information, as it would be impracticable to compile such information on an asset-by-asset basis. 2018 2017 Gross amount at beginning $ 20,110 $ 16,121 Additions during period: Acquisitions through foreclosure — — Other acquisitions (1)(2) 5 2,788 Communications infrastructure construction and improvements 1,567 1,063 Purchase of land interests 56 81 Sustaining capital expenditures 85 56 Other (3) 64 46 Total additions 1,777 4,034 Deductions during period: Cost of real estate sold or disposed (21 ) (45 ) Other — — Total deductions: (21 ) (45 ) Balance at end $ 21,866 $ 20,110 (1) Inclusive of changes between the final purchase price allocation and the preliminary purchase price allocations. (2) Includes acquisitions of communications infrastructure. (3) Predominately relates to the purchase of property and equipment under capital leases and installment land purchases. 2018 2017 Gross amount of accumulated depreciation at beginning $ (7,303 ) $ (6,446 ) Additions during period: Depreciation (1,057 ) (890 ) Total additions (1,057 ) (890 ) Deductions during period: Amount for assets sold or disposed 18 26 Other 1 7 Total deductions 19 33 Balance at end $ (8,341 ) $ (7,303 )

Basis of Presentation (Details)

Basis of Presentation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Ground Lease Agreement Initial Term	five years
Subject to Capital Lease with Sprint, TMO, or AT&T [Member]
Tower count as a percentage of total towers	53.00%
Leased or Operated Under Sprint Agreement [Member]
Ground Lease Agreement Initial Term	32
Purchase Option Price	$ 2,300
Tower count as a percentage of total towers	16.00%
Leased or Operated Under T-Mobile Agreement [Member]
Ground Lease Agreement Initial Term	28
Tower count as a percentage of total towers	15.00%
T-Mobile [Member]
Purchase Option Price	$ 2,000
AT&T lease or sublease in accordance with TMO Agreement [Member]
Purchase Option Price	$ 405
Tower count as a percentage of total towers	0.00%
AT&T Prior to 2025 in accordance with TMO agreement [Member]
Purchase Option Price	$ 10
AT&T [Member]
Ground Lease Agreement Initial Term	28
Purchase Option Price	$ 4,200
Tower count as a percentage of total towers	22.00%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue Recognition Non-cancelable Lease Term	five to 15 years
Capitalized Labor Costs	$ 212	$ 92	$ 86
Useful life of site rental contracts and customer relationships (years)	20 years
Revenue Recognition Non-cancelable Term for Non-wireless Contracts Range, Minimum	three to 20 years
Portion of company site rental costs that are ground lease expenses	50.00%
Ground Lease Agreement Initial Term	five years
Percentage of tax position that is likely of being realized upon ultimate settlement	50.00%
Asset write-down charges	$ 26	17	34
Revenue, Performance Obligation, Description of Payment Terms	45 to 60 days
Revenue, Remaining Performance Obligation, Amount	$ 2,300	2,100
Contract with Customer, Liability, Revenue Recognized	400
Minimum [Member]
Impact of adoption of ASU 2016-02	5,000
Maximum [Member]
Impact of adoption of ASU 2016-02	$ 7,000
Wireless Infrastructure [Member]
Estimated useful life, maximum, in years	20 years
Wireless Infrastructure [Member] | Minimum [Member]
Estimated useful life, maximum, in years	1 year
Wireless Infrastructure [Member] | Maximum [Member]
Estimated useful life, maximum, in years	20 years
Towers [Member]
Estimated useful life, maximum, in years	20 years
Property, Plant and Equipment [Member]
Asset write-down charges	$ 22	14	$ 27
Other Current Assets [Member]
Straight-Line Site Rental Revenues	92	86
Deferred Revenue [Domain]
Straight-Line Site Rental Revenues	$ 1,400	$ 1,300
Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share (in shares)	15

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Interest Expense and Amortization of Deferred Financing Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Interest expense on debt obligations	$ 635	$ 582	$ 501
Amortization of deferred financing costs and adjustments on long-term debt, net	21	19	19
Capitalized Interest	(15)	(12)	(7)
Other	1	2	2
Total	$ 642	$ 591	$ 515

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Per Share Information) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017	[1]	Sep. 30, 2017	[1]	Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Income (Loss) from Continuing Operations																	$ 671	$ 445	$ 357
Dividends, Preferred Stock																	(113)	(58)	(33)
Net income (loss) attributable to CCIC common stockholders																	$ 558	$ 387	$ 324
Weighted-average common shares outstanding:
Basic weighted-average number of common stock outstanding																	413	382	340
Diluted weighted-average number of common shares outstanding																	415	383	341
Net income (loss) attributable to CCIC common stockholders, after deduction of dividends on preferred stock, per common share:
Basic (in dollars per share)	$ 0.45		$ 0.33		$ 0.37		$ 0.21		$ 0.17		$ 0.22		$ 0.31		$ 0.33		$ 1.35	$ 1.01	$ 0.95
Diluted (in dollars per share)	$ 0.44		$ 0.33		$ 0.36		$ 0.21		$ 0.17		$ 0.21		$ 0.31		$ 0.33		1.34	1.01	0.95
Common Stock, Dividends, Per Share, Declared																	$ 4.28	$ 3.90	$ 3.61
Stock Options and Restricted Stock Awards [Member]
Weighted-average common shares outstanding:
Effect of assumed dilution from potential common shares relating to stock options and restricted stock awards																	2	1	1
[1]	The sum of quarterly information may not agree to year to date information due to rounding.

Acquisitions (Details)

Acquisitions (Details) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)$ / shares	Dec. 31, 2016USD ($)$ / shares
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Depreciation and Amortization			$ 247	$ 316
Business Acquisition, Pro Forma Revenue			5,050	4,865
Fiber Miles		65,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual			314
Business Acquisition, Pro Forma Income (Loss) Before Income Taxes	[1],[2]		541	367	[3]
Business Combination, Pro Forma Benefit (Provision) for Income Taxes	[4]		(29)	(21)
Business Acquisition, Pro Forma Net Income (Loss)	[1],[2]		$ 512	$ 346	[3]
Business Acquisition, Pro Forma Earnings Per Share, Basic | $ / shares	[2],[5]		$ 0.89	$ 0.51
Business Acquisition, Pro Forma Earnings Per Share, Diluted | $ / shares	[2],[5]		$ 0.88	$ 0.51
Business Combination, Pro Forma Stock-Based Compensation, Acquisition and Integration Costs			$ 120
FiberNet Acquisition [Member]
Business Acquisition [Line Items]
Consideration transferred		$ 1,500
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets		52
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		438
Business Acquisition, Goodwill, Expected Tax Deductible Amount	[6]	778
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	[7]	327
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets		2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities		(41)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities		(35)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	[8]	$ 1,521
Fiber Miles Acquired		11,500
Business Acquisition, Date of Acquisition Agreement		Jan. 17, 2017
TDC [Member]
Business Acquisition [Line Items]
Consideration transferred		$ 461
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		107
Business Acquisition, Goodwill, Expected Tax Deductible Amount		211
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 140
Tower Count		330
Wilcon Acquisition [Member]
Business Acquisition [Line Items]
Consideration transferred		$ 600
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		150
Business Acquisition, Goodwill, Expected Tax Deductible Amount		360
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 140
Fiber Miles Acquired		1,900
Business Acquisition, Date of Acquisition Agreement		Jun. 26, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue		$ 40
Lightower Acquisition [Member]
Business Acquisition [Line Items]
Consideration transferred		7,100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets		99
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		2,194
Business Acquisition, Goodwill, Expected Tax Deductible Amount	[9]	3,171
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	[10]	2,177
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets		27
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities		(176)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities		(342)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	[11]	$ 7,150
Fiber Miles Acquired		32,000
Business Acquisition, Date of Acquisition Agreement		Nov. 1, 2017
Top Metro Markets [Domain] | FiberNet Acquisition [Member]
Business Acquisition [Line Items]
Fiber Miles Acquired		6,000
[1]	For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to depreciation and amortization of $247 million and $316 million, respectively, related to property and equipment and intangibles recorded as a result of the 2017 Acquisitions.
[2]	Pro forma amounts include the impact of the interest expense and common stock share issuances associated with the related debt and equity financings for the 2017 Acquisitions (see above and notes 8 and 11).
[3]	Amounts are inclusive of a total of $120 million of Lightower stock-based compensation expense and acquisition and integration costs.
[4]	For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to the benefit (provision) for income tax as a result of the Company's REIT status. The vast majority of the assets and related income from the FiberNet Acquisition, the Wilcon Acquisition, and the Lightower Acquisition are included in the Company's REIT. The remaining assets are included in the Company's TRS. For purposes of the unaudited pro forma financial results, an adjustment has been made to reflect the additional tax impact of the income related to the TRS assets.
[5]	Pro forma amounts include the impact of the preferred stock dividends related to the Mandatory Convertible Preferred Stock Offering (as defined in note 11) for the Lightower Acquisition (see above and note 11).
[6]	The final purchase price allocation for the FiberNet Acquisition resulted in the recognition of goodwill based on:•the Company's expectation to leverage the FiberNet fiber footprint to support new small cells and fiber solutions,•the complementary nature of the FiberNet fiber to the Company's existing fiber assets and its location in top metro markets where the Company expects to see wireless carrier network investments,•the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and•other intangibles not qualified for separate recognition, including the assembled workforce.
[7]	Predominantly comprised of site rental contracts and tenant relationships.
[8]	The vast majority of the assets have been included in the Company's REIT. As such, no deferred taxes were recorded in connection with the FiberNet Acquisition
[9]	The final purchase price allocation for the Lightower Acquisition resulted in the recognition of goodwill based on:•the Company's expectation to leverage the Lightower fiber footprint to support new small cells and fiber solutions,•the complementary nature of the Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,•the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and•other intangibles not qualified for separate recognition, including the assembled workforce.
[10]	Predominantly comprised of site rental contracts and tenant relationships.
[11]	The vast majority of the assets have been included in the Company's REIT. As such, no deferred taxes were recorded in connection with the Lightower Acquisition.

Revenue (Details)

Revenue (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Revenue from Contract with Customer [Abstract]
Weighted Average Remaining Term Of Tenant Leases at the Tenant's Option	5 years
Operating Leases, Future Minimum Payments Receivable, 2019	$ 3,968
Operating Leases, Future Minimum Payments Receivable, 2020	3,761
Operating Leases, Future Minimum Payments Receivable, 2021	3,552
Operating Leases, Future Minimum Payments Receivable, 2022	3,317
Operating Leases, Future Minimum Payments Receivable, in 2023	2,587
Operating Leases, Future Minimum Payments Receivable, Thereafter	6,229
Operating Leases, Future Minimum Payments Receivable	$ 23,414

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 22,242	$ 20,433
Less: accumulated depreciation		(8,566)	(7,500)
Total property and equipment, net		13,676	12,933
Depreciation expense		1,100	915	$ 833
Capital Leased Assets, Gross		4,400
Accumulated Depreciation on Capital Lease Assets		1,900
Land owned in fee and perpetual easements [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment	[1]	1,981	1,859
Buildings [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 134	119
Property, Plant and Equipment, Useful Life		40 years
Wireless Infrastructure [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 18,709	17,184
Property, Plant and Equipment, Useful Life		20 years
Information technology assets and other [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 443	372
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 975	$ 899
Minimum [Member] | Wireless Infrastructure [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		1 year
Minimum [Member] | Information technology assets and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		2 years
Maximum [Member] | Wireless Infrastructure [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		20 years
Maximum [Member] | Information technology assets and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life		7 years
[1]	Includes land owned in fee and perpetual easements.

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Goodwill and Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		20 years
Goodwill Period Start		$ 10,021		$ 5,758
Goodwill Period End		10,078		10,021	$ 5,758
Finite-lived intangible assets, gross		8,281	[1]	8,286
Accumulated amortization of intangible assets		(2,765)		(2,324)
Finite-lived intangible assets, net		5,516		5,962
Estimated annual amortization expense related to intangible assets - 2019		445
Estimated annual amortization expense related to intangible assets - 2020		444
Estimated annual amortization expense related to intangible assets - 2021		444
Estimated annual amortization expense related to intangible assets - 2022		443
Estimated annual amortization expense related to intangible assets - 2023		443
Site Rental Contracts and Customer Relationships [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		7,787	[1]	7,782
Accumulated amortization of intangible assets		(2,578)		(2,156)
Finite-lived intangible assets, net		5,209		5,626
Other Intangible Assets [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		494	[1]	504
Accumulated amortization of intangible assets		(187)		(168)
Finite-lived intangible assets, net		307		336
Other Acquired Goodwill [Domain]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Additions due to acquisitions		57		12
FiberNet Acquisition [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Additions due to acquisitions	[2]			778
Wilcon Acquisition [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Additions due to acquisitions	[2]			358
Lightower Acquisition [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Additions due to acquisitions				3,115
Depreciation, Amortization and Accretion [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Amortization expense		428		314	265
Site Rental Costs of Operations [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Amortization expense		17		18	19
Total Amortization Expense [Member]
Goodwill and Finite-Lived Intangible Assets [Line Items]
Amortization expense		$ 445		$ 332	$ 284
[1]	During the year ended December 31, 2018, intangible assets additions (primarily site rental contracts and tenant relationships) from acquisitions had a weighted average amortization period of approximately 20 years.
[2]	The final purchase price allocations for the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition resulted in the recognition of goodwill in the Fiber segment based on:•the Company's expectation to leverage the FiberNet, Wilcon and Lightower fiber footprint to support new small cells and fiber solutions,•the complementary nature of the FiberNet, Wilcon and Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,•the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and•other intangibles not qualified for separate recognition, including the assembled workforce. See note 3.

Other Liabilities (Details)

Other Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities [Line Items]
Asset Retirement Obligation, Accretion Expense	$ 14	$ 13	$ 11
Other Liabilities, non-current	2,759	2,554
Estimated Future Undiscounted Cash Flows Expected To Be Paid Relating To Asset Retirement Obligations	1,100
Amortization of Below Market Tenant Lease	69	37	34
Accrued Payroll and Other Compensation	157	141
Above Market Leases [Member]
Other Liabilities [Line Items]
Amortization of Above Market Leases	18	19	$ 21
AML Amortization expense, 2019
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	17
AML Amortization expense, 2020
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	16
AML Amortization expense, 2021
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	15
AML Amortization expense, 2022
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	14
AML Amortization expense, 2023
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	13
BML Amortization expense, 2019
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	62
BML Amortization expense, 2020
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	55
BML Amortization expense, 2021
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	52
BML Amortization expense, 2022
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	47
BML Amortization expense, 2023
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	43
customer prepaid rent [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	1,267	1,077
deferred ground lease payable [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	603	560
Above Market Leases [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	181	202
deferred credits [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	499	532
asset retirement obligations [Member]
Other Liabilities [Line Items]
Asset Retirement Obligation	192	174
Deferred Tax Liability, noncurrent [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	7	5
Other Liabilities [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	$ 10	$ 4

Debt and Other Obligations (Ind

Debt and Other Obligations (Indebtedness) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2015
Debt Instrument [Line Items]
Original issue date							Oct. 1, 2012
Debt Instrument, Maturity Date							Jan. 1, 2023
Total debt and other obligations		$ 16,682		$ 16,159
Less: current maturities and short-term debt and other current obligations		107		115
Non-current portion of long-term debt and other long-term obligations		16,575		16,044
Debt Instrument, Interest Rate, Stated Percentage							5.25%
Debt Instrument, Face Amount							$ 1,650
Securitized Debt [Member]
Debt Instrument [Line Items]
Total debt and other obligations		3,283		4,552
Unsecured Debt [Member]
Debt Instrument [Line Items]
Total debt and other obligations		$ 13,399		11,607
Minimum [Member] | Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity Date Range		one year
Minimum [Member] | 2016 Revolver [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Commitment Fee Percentage		0.125%
Maximum [Member] | Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity Date Range		30 years
Maximum [Member] | 2016 Revolver [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Commitment Fee Percentage		0.35%
Fixed Rate Securitized Debt January 2010 Tower Revenue Notes 3 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		Jan. 1, 2010
Debt Instrument, Maturity Date	[1],[2]	Jan. 1, 2040
Total debt and other obligations		$ 0		1,246
Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 6 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		Aug. 1, 2010
Debt Instrument, Maturity Date	[1],[2]	Aug. 1, 2040
Total debt and other obligations		$ 0		995
2015 Tower Revenue Notes 3.222% due 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 300
2015 Tower Revenue Notes 3.222% due 2042 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		May 1, 2015
Debt Instrument, Maturity Date	[1],[2]	May 1, 2042
Total debt and other obligations		$ 298		297
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.20%
2015 Tower Revenue Notes 3.663% due 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 700
2015 Tower Revenue Notes 3.663% due 2045 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		May 1, 2015
Debt Instrument, Maturity Date	[1],[2]	May 1, 2045
Total debt and other obligations		$ 693		692
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.70%
2018 Tower Revenue Notes 3.720% due 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Jul. 1, 2043
Debt Instrument, Interest Rate, Stated Percentage		3.72%
Debt Instrument, Face Amount		$ 250
2018 Tower Revenue Notes 3.720% due 2043 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		Jul. 1, 2018
Debt Instrument, Maturity Date	[1],[2]	Jul. 1, 2043
Total debt and other obligations		$ 247		0
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.70%
2018 Tower Revenue Notes 4.241% due 2048 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Jul. 1, 2048
Debt Instrument, Interest Rate, Stated Percentage		4.241%
Debt Instrument, Face Amount		$ 750
2018 Tower Revenue Notes 4.241% due 2048 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		Jul. 1, 2018
Debt Instrument, Maturity Date	[1],[2]	Jul. 1, 2048
Total debt and other obligations		$ 742		0
Debt Instrument, Interest Rate, Stated Percentage	[3]	4.20%
3.849% Secured Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Dec. 1, 2012
Debt Instrument, Maturity Date		Apr. 1, 2023					Apr. 1, 2023
Total debt and other obligations		$ 994		993
Debt Instrument, Interest Rate, Stated Percentage		3.90%	[3]				3.849%
Fixed Rate Debt 2009 Securitized Notes A-1 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		Jul. 1, 2009
Debt Instrument, Maturity Date	[4]	Aug. 1, 2019
Total debt and other obligations		$ 12		32
Debt Instrument, Interest Rate, Stated Percentage	[3]	6.30%
Fixed Rate Debt 2009 Securitized Notes A-2 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Original issue date		Jul. 1, 2009
Debt Instrument, Maturity Date	[4]	Aug. 1, 2029
Total debt and other obligations		$ 70		70
Debt Instrument, Interest Rate, Stated Percentage	[3]	9.00%
Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity Date Range Beginning		1 year
Total debt and other obligations	[5]	$ 227		$ 227
Percentage Of Debt Instrument Interest Rate Stated	[3]	Various
Debt Instrument Maturity Date Range Ending		30 years
Capital Lease Obligations and Other [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		10.00%
2016 Revolver [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Jun. 1, 2023		Aug. 1, 2022	Jan. 1, 2021
Availability on revolver		$ 3,200
2016 Revolver [Member] | Bank Debt [Member]
Debt Instrument [Line Items]
Original issue date		Jan. 1, 2016
Debt Instrument, Maturity Date		Jun. 1, 2023
Total debt and other obligations		$ 1,075	[6]	$ 980
Debt Instrument, Interest Rate, Stated Percentage	[7]	3.80%
2016 Revolver [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.00%
2016 Revolver [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		1.75%
2016 Term Loan A [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date				Jan. 1, 2022	Jan. 1, 2021
2016 Term Loan A [Member] | Bank Debt [Member]
Debt Instrument [Line Items]
Original issue date		Jan. 1, 2016
Debt Instrument, Maturity Date		Jun. 1, 2023
Total debt and other obligations		$ 2,354		$ 2,397
Debt Instrument, Interest Rate, Stated Percentage	[7]	3.80%
Debt Instrument, Face Amount					$ 2,000
5.250% Senior Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Oct. 1, 2012
Debt Instrument, Maturity Date		Jan. 1, 2023
Total debt and other obligations		$ 1,641		1,639
Debt Instrument, Interest Rate, Stated Percentage	[3]	5.30%
4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						4.875%
4.875% Senior Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Apr. 1, 2014				Apr. 1, 2014
Debt Instrument, Maturity Date		Apr. 1, 2022				Apr. 1, 2022
Total debt and other obligations		$ 844		842
Debt Instrument, Interest Rate, Stated Percentage		4.90%	[3]			4.875%
Debt Instrument, Face Amount						$ 850
Senior Unsecured 2016 Notes 3.40% [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Feb. 1, 2016
Debt Instrument, Maturity Date		Feb. 1, 2021
Total debt and other obligations		$ 850		850
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.40%
Senior Unsecured 2016 Notes 4.450% [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Feb. 1, 2016
Debt Instrument, Maturity Date		Feb. 1, 2026
Total debt and other obligations		$ 892		891
Debt Instrument, Interest Rate, Stated Percentage	[3]	4.50%
Senior Unsecured 2016 Notes 3.7% [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		May 1, 2016
Debt Instrument, Maturity Date		Jun. 1, 2026
Total debt and other obligations		$ 744		743
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.70%
2.250% Senior Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Sep. 1, 2016
Debt Instrument, Maturity Date		Sep. 1, 2021
Total debt and other obligations		$ 697		$ 695
Debt Instrument, Interest Rate, Stated Percentage	[3]	2.30%
4.000% Senior Unsecured Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Feb. 1, 2017		Feb. 1, 2017
Debt Instrument, Maturity Date		Mar. 1, 2027		Mar. 1, 2027
Total debt and other obligations		$ 494		$ 494
Debt Instrument, Interest Rate, Stated Percentage		4.00%	[3]	4.00%
Debt Instrument, Face Amount				$ 500
4.750% Senior Unsecured Notes [Member] [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		May 1, 2017		May 1, 2017
Debt Instrument, Maturity Date		May 1, 2047		May 1, 2047
Total debt and other obligations		$ 343		$ 343
Debt Instrument, Interest Rate, Stated Percentage		4.80%	[3]	4.75%
Debt Instrument, Face Amount				$ 350
August 2017 Senior Unsecured 3.200% Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Aug. 1, 2017
Debt Instrument, Maturity Date		Sep. 1, 2024		Sep. 1, 2024
Total debt and other obligations		$ 743		$ 742
Debt Instrument, Interest Rate, Stated Percentage		3.20%	[3]	3.20%
Debt Instrument, Face Amount				$ 750
August 2017 Senior Unsecured 3.650% Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Aug. 1, 2017
Debt Instrument, Maturity Date		Sep. 1, 2027		Sep. 1, 2027
Total debt and other obligations		$ 992		$ 991
Debt Instrument, Interest Rate, Stated Percentage		3.70%	[3]	3.65%
Debt Instrument, Face Amount				$ 1,000
3.150% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Jul. 1, 2023
Debt Instrument, Interest Rate, Stated Percentage		3.15%
Debt Instrument, Face Amount		$ 750
3.150% Senior Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Jan. 1, 2018
Debt Instrument, Maturity Date		Jul. 1, 2023
Total debt and other obligations		$ 742		0
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.20%
3.800% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Feb. 1, 2028
Debt Instrument, Interest Rate, Stated Percentage		3.80%
Debt Instrument, Face Amount		$ 1,000
3.800% Senior Notes [Member] | High Yield Bonds [Member]
Debt Instrument [Line Items]
Original issue date		Jan. 1, 2018
Debt Instrument, Maturity Date		Feb. 1, 2028
Total debt and other obligations		$ 988		$ 0
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.80%
Fixed Rate Securitized Debt 2010 Tower Revenue Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Increase (Decrease)		5.00%
August 2010 Tower Revenue Notes ARD [Domain] | Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 5 [Member] | Securitized Debt [Member]
Debt Instrument [Line Items]
Total debt and other obligations								$ 250
[1]	If the respective series of Tower Revenue Notes are not paid in full on or prior to an applicable anticipated repayment date, then Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes, and additional interest (of an additional approximately 5% per annum) will accrue on the respective Tower Revenue Notes. As of December 31, 2018, the Tower Revenue Notes have principal amounts of $300 million, $250 million, $700 million and $750 million, with anticipated repayment dates in 2022, 2023, 2025 and 2028, respectively.
[2]	The Tower Revenue Notes, Series 2010-3 ("January 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2010-6 ("August 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2015-1 and 2015-2 ("May 2015 Tower Revenue Notes") and Tower Revenue Notes, Series 2018-1 and 2018-2 ("July 2018 Tower Revenue Notes") are collectively referred to herein as "Tower Revenue Notes."
[3]	Represents the weighted-average stated interest rate.
[4]	The Secured Notes, Series 2009-1, Class A-1 and Secured Notes, Series 2009-1, Class A-2 are collectively referred to herein as "2009 Securitized Notes."
[5]	The Company's capital leases and other obligations relate to land, fiber, vehicles, and other assets and bear interest rates ranging up to 10% and mature in periods ranging from less than one year to approximately 30 years.
[6]	As of December 31, 2018, the undrawn availability under the 2016 Revolver was $3.2 billion.
[7]	The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.000% to 1.750%, based on the Company's senior unsecured debt rating. The Company pays a commitment fee ranging from 0.125% to 0.350%, based on the Company's senior unsecured debt rating, per annum on the undrawn available amount under the 2016 Revolver.

Debt and Other Obligations (Tex

Debt and Other Obligations (Textuals) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2015
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 1,650
Debt Instrument, Maturity Date							Jan. 1, 2023
Extinguishment of Debt, Amount		$ 2,250		$ 0	$ 4,026
Debt Instrument, Issuance Date							Oct. 1, 2012
Debt Instrument, Interest Rate, Stated Percentage							5.25%
Debt and Capital Lease Obligations		$ 16,682		$ 16,159
2016 Revolver [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date		Jun. 1, 2018		Aug. 1, 2017
Line of Credit Facility, Change in Borrowing Capacity		$ 750		$ 1,000
Line of Credit Facility, Maximum Borrowing Capacity		$ 4,250		$ 3,500
Debt Instrument, Maturity Date		Jun. 1, 2023		Aug. 1, 2022	Jan. 1, 2021
Extinguishment of Debt, Amount					$ 500
2016 Term Loan A [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date				Feb. 1, 2017
Debt Instrument, Maturity Date				Jan. 1, 2022	Jan. 1, 2021
4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						4.875%
January 2018 Senior Note [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date		Jan. 1, 2018
3.150% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 750
Debt Instrument, Maturity Date		Jul. 1, 2023
Debt Instrument, Interest Rate, Stated Percentage		3.15%
3.800% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 1,000
Debt Instrument, Maturity Date		Feb. 1, 2028
Debt Instrument, Interest Rate, Stated Percentage		3.80%
July 2018 Tower Revenue Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 1,000
Debt Instrument, Issuance Date		Jul. 1, 2018
2018 Tower Revenue Notes 3.720% due 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 250
Debt Instrument, Maturity Date		Jul. 1, 2043
Debt Instrument, Interest Rate, Stated Percentage		3.72%
2018 Tower Revenue Notes 4.241% due 2048 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 750
Debt Instrument, Maturity Date		Jul. 1, 2048
Debt Instrument, Interest Rate, Stated Percentage		4.241%
2018 Tower Revenue Notes Risk Retention Tranche [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 53
Securitized Debt [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations		$ 3,283		$ 4,552
Securitized Debt [Member] | 2018 Tower Revenue Notes 3.720% due 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	[1],[2]	Jul. 1, 2043
Debt Instrument, Issuance Date		Jul. 1, 2018
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.70%
Debt and Capital Lease Obligations		$ 247		0
Securitized Debt [Member] | 2018 Tower Revenue Notes 4.241% due 2048 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	[1],[2]	Jul. 1, 2048
Debt Instrument, Issuance Date		Jul. 1, 2018
Debt Instrument, Interest Rate, Stated Percentage	[3]	4.20%
Debt and Capital Lease Obligations		$ 742		0
Bank Debt [Member] | 2016 Revolver [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 2,500
Debt Instrument, Maturity Date		Jun. 1, 2023
Debt Instrument, Issuance Date		Jan. 1, 2016
Debt Instrument, Interest Rate, Stated Percentage	[4]	3.80%
Debt and Capital Lease Obligations		$ 1,075	[5]	980
Bank Debt [Member] | 2016 Term Loan A [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					2,000
Debt Instrument, Maturity Date		Jun. 1, 2023
Debt Instrument, Issuance Date		Jan. 1, 2016
Debt Instrument, Interest Rate, Stated Percentage	[4]	3.80%
Debt and Capital Lease Obligations		$ 2,354		2,397
January 2010 Tower Revenue Notes [Member]
Debt Instrument [Line Items]
Repayments of Debt						$ 300
3.849% Secured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 1,000
High Yield Bonds [Member] | May 2016 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 1,000
Debt Instrument, Issuance Date					May 1, 2016
High Yield Bonds [Member] | 4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount						$ 850
Debt Instrument, Maturity Date		Apr. 1, 2022				Apr. 1, 2022
Debt Instrument, Issuance Date		Apr. 1, 2014				Apr. 1, 2014
Debt Instrument, Interest Rate, Stated Percentage		4.90%	[3]			4.875%
Debt and Capital Lease Obligations		$ 844		842
High Yield Bonds [Member] | 4.000% Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 500
Debt Instrument, Maturity Date		Mar. 1, 2027		Mar. 1, 2027
Debt Instrument, Issuance Date		Feb. 1, 2017		Feb. 1, 2017
Debt Instrument, Interest Rate, Stated Percentage		4.00%	[3]	4.00%
Debt and Capital Lease Obligations		$ 494		$ 494
High Yield Bonds [Member] | 2016 Senior Unsecured Notes [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 1,500
Debt Instrument, Issuance Date					Feb. 1, 2016
High Yield Bonds [Member] | 3.400% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 250
Debt Instrument, Maturity Date					Feb. 1, 2021
Debt Instrument, Interest Rate, Stated Percentage					3.40%
High Yield Bonds [Member] | 3.700% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 750
Debt Instrument, Maturity Date					Jun. 1, 2026
Debt Instrument, Interest Rate, Stated Percentage					3.70%
High Yield Bonds [Member] | 4.450% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 900
Debt Instrument, Maturity Date					Feb. 1, 2026
Debt Instrument, Interest Rate, Stated Percentage					4.45%
High Yield Bonds [Member] | 4.750% Senior Unsecured Notes [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 350
Debt Instrument, Maturity Date		May 1, 2047		May 1, 2047
Debt Instrument, Issuance Date		May 1, 2017		May 1, 2017
Debt Instrument, Interest Rate, Stated Percentage		4.80%	[3]	4.75%
Debt and Capital Lease Obligations		$ 343		$ 343
High Yield Bonds [Member] | August 2017 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 1,750
Debt Instrument, Issuance Date				Aug. 1, 2017
High Yield Bonds [Member] | August 2017 Senior Unsecured 3.200% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 750
Debt Instrument, Maturity Date		Sep. 1, 2024		Sep. 1, 2024
Debt Instrument, Issuance Date		Aug. 1, 2017
Debt Instrument, Interest Rate, Stated Percentage		3.20%	[3]	3.20%
Debt and Capital Lease Obligations		$ 743		$ 742
High Yield Bonds [Member] | August 2017 Senior Unsecured 3.650% Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 1,000
Debt Instrument, Maturity Date		Sep. 1, 2027		Sep. 1, 2027
Debt Instrument, Issuance Date		Aug. 1, 2017
Debt Instrument, Interest Rate, Stated Percentage		3.70%	[3]	3.65%
Debt and Capital Lease Obligations		$ 992		$ 991
High Yield Bonds [Member] | 3.150% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Jul. 1, 2023
Debt Instrument, Issuance Date		Jan. 1, 2018
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.20%
Debt and Capital Lease Obligations		$ 742		0
High Yield Bonds [Member] | 3.800% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Feb. 1, 2028
Debt Instrument, Issuance Date		Jan. 1, 2018
Debt Instrument, Interest Rate, Stated Percentage	[3]	3.80%
Debt and Capital Lease Obligations		$ 988		0
High Yield Bonds [Member] | 3.849% Secured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Apr. 1, 2023					Apr. 1, 2023
Debt Instrument, Issuance Date		Dec. 1, 2012
Debt Instrument, Interest Rate, Stated Percentage		3.90%	[3]				3.849%
Debt and Capital Lease Obligations		$ 994		993
2.250% Senior Notes [Member] | September 2016 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 700
Debt Instrument, Maturity Date					Sep. 1, 2021
Debt Instrument, Issuance Date					Sep. 1, 2016
Debt Instrument, Interest Rate, Stated Percentage					2.25%
2.381% Secured Notes [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount					$ 500
2.381% Secured Notes [Member] | September 2016 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					2.381%
Repayments of Debt					$ 500
Issuance of debt obligation [Member] | 4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from Issuance of Debt						$ 839
August 2010 Tower Revenue Notes ARD [Domain] | Securitized Debt [Member] | Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 5 [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations								$ 250
Collateral Pledged [Member]
Debt Instrument [Line Items]
Debt Instrument, PPE Collaterized Amount		$ 1,000
Additional Principal Incurred [Member] | 2016 Term Loan A [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 500
Additional Principal Incurred [Member] | Bank Debt [Member] | Senior Unsecured 364-Day Revolving Credit Facility [Domain]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					1,000
February 2016 Senior Note Upsizing [Member] | High Yield Bonds [Member] | 3.400% Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 600
Debt Instrument, Interest Rate, Stated Percentage					3.40%
[1]	If the respective series of Tower Revenue Notes are not paid in full on or prior to an applicable anticipated repayment date, then Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes, and additional interest (of an additional approximately 5% per annum) will accrue on the respective Tower Revenue Notes. As of December 31, 2018, the Tower Revenue Notes have principal amounts of $300 million, $250 million, $700 million and $750 million, with anticipated repayment dates in 2022, 2023, 2025 and 2028, respectively.
[2]	The Tower Revenue Notes, Series 2010-3 ("January 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2010-6 ("August 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2015-1 and 2015-2 ("May 2015 Tower Revenue Notes") and Tower Revenue Notes, Series 2018-1 and 2018-2 ("July 2018 Tower Revenue Notes") are collectively referred to herein as "Tower Revenue Notes."
[3]	Represents the weighted-average stated interest rate.
[4]	The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.000% to 1.750%, based on the Company's senior unsecured debt rating. The Company pays a commitment fee ranging from 0.125% to 0.350%, based on the Company's senior unsecured debt rating, per annum on the undrawn available amount under the 2016 Revolver.
[5]	As of December 31, 2018, the undrawn availability under the 2016 Revolver was $3.2 billion.

Debt and Other Obligations (Sch

Debt and Other Obligations (Scheduled Contractual Maturities) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Contractual Maturities - 2019	$ 107
Contractual Maturities - 2020	142
Contractual Maturities - 2021	1,702
Contractual Maturities - 2022	1,087
Contractual Maturities - 2023	6,363
Contractual Maturities - Thereafter	7,390
Total Cash Obligations	16,791
Unamortized Discounts	(109)
Total Debt and Other Obligations Outstanding	$ 16,682
Fixed Rate Securitized Debt 2010 Tower Revenue Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Increase (Decrease)	5.00%

Debt and Other Obligations (Deb

Debt and Other Obligations (Debt Purchases and Repayments) (Details) - USD ($) $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2018

[3]

Sep. 30, 2018

[3]

Jun. 30, 2018

[3]

Mar. 31, 2018

[3]

Dec. 31, 2017

[3]

Sep. 30, 2017

[3]

Jun. 30, 2017

[3]

Mar. 31, 2017

[3]

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Debt Instrument [Line Items]

Principal Amount

$ 2,250

$ 0

$ 4,026

Cash Paid

2,346

[1]

0

4,045

[2]

Gains (losses) on retirement of long-term obligations

$ 0

$ (32)

$ (3)

$ (71)

$ 0

$ 0

$ 0

$ (4)

(106)

[4]

(4)

[5]

(52)

[6]

2012 Credit Facility [Member]

Debt Instrument [Line Items]

Principal Amount

0

Cash Paid

[2]

0

Gains (losses) on retirement of long-term obligations

[6]

(2)

Fixed Rate Securitized Debt January 2010 Tower Revenue Notes 3 [Member]

Debt Instrument [Line Items]

Principal Amount

1,250

Cash Paid

[1]

1,318

Gains (losses) on retirement of long-term obligations

[4]

(71)

2016 Term Loan A [Member]

Debt Instrument [Line Items]

Principal Amount

0

0

Cash Paid

0

[1]

0

Gains (losses) on retirement of long-term obligations

(3)

[4]

$ (4)

[5]

Variable Rate 2012 Term Loans Tranche A [Member]

Debt Instrument [Line Items]

Principal Amount

629

Cash Paid

[2]

629

Gains (losses) on retirement of long-term obligations

[6]

(2)

Variable Rate 2012 Term Loans Tranche B [Member]

Debt Instrument [Line Items]

Principal Amount

2,247

Cash Paid

[2]

2,247

Gains (losses) on retirement of long-term obligations

[6]

(27)

Fixed Rate Securitized Debt January 2010 Tower Revenue Notes 2 [Member]

Debt Instrument [Line Items]

Principal Amount

350

Cash Paid

[2]

353

Gains (losses) on retirement of long-term obligations

[6]

(3)

Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 5 [Member]

Debt Instrument [Line Items]

Principal Amount

300

Cash Paid

[2]

307

Gains (losses) on retirement of long-term obligations

[6]

(8)

Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 6 [Member]

Debt Instrument [Line Items]

Principal Amount

1,000

Cash Paid

[1]

1,028

Gains (losses) on retirement of long-term obligations

[4]

$ (32)

2.381% Secured Notes [Member]

Debt Instrument [Line Items]

Principal Amount

500

Cash Paid

[2]

509

Gains (losses) on retirement of long-term obligations

[6]

$ (10)

[1]

Exclusive of accrued interest.

[2]

Exclusive of accrued interest.

[3]

The sum of quarterly information may not agree to year to date information due to rounding.

[4]

Inclusive of the write off of the respective deferred financing costs.

[5]

The losses related to write off of deferred financing costs

[6]

Inclusive of the write off of the respective deferred financing costs.

Fair Value Disclosures (Estimat

Fair Value Disclosures (Estimated Fair Values and Carrying Amounts of Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, carrying value	$ 277	$ 314	$ 568
Cash and cash equivalents, fair value	277	314
Restricted cash, carrying value	136	126
Restricted cash, fair value	136	126
Debt and other obligations, carrying amount	16,682	16,159
Debt and other obligations, fair value	$ 16,562	$ 16,644

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Stock Compensation Plan [Member]
Operating Loss Carryforwards	$ 237
Foreign Tax Authority [Member]
Operating Loss Carryforwards	50
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	600
Domestic Tax Authority [Member]
Operating Loss Carryforwards	$ 1,500
Maximum [Member] | Foreign Tax Authority [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Maximum [Member] | State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
Maximum [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
Minimum [Member] | Foreign Tax Authority [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2022
Minimum [Member] | State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2019
Minimum [Member] | Domestic Tax Authority [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2025

Income Taxes (Income (Loss) fro

Income Taxes (Income (Loss) from Continuing Operations before Income Taxes) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Domestic		$ 667	$ 451	$ 349
Foreign	[1]	23	20	25
Income (loss) before income taxes		$ 690	$ 471	$ 374
[1]	Inclusive of income (loss) before income taxes from Puerto Rico.

Income Taxes (Benefit (Provisio

Income Taxes (Benefit (Provision) for Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017	[1]	Sep. 30, 2017	[1]	Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)																	$ (5)	$ (3)	$ 0
Current Foreign																	(7)	(6)	(7)
Current State																	(5)	(2)	(1)
Total current																	(17)	(11)	(8)
Deferred Federal																	0	(18)	(8)
Deferred Foreign																	(2)	3	(1)
Total deferred																	(2)	(15)	(9)
Benefit (provision) for income taxes	$ (5)		$ (5)		$ (5)		$ (4)		$ (15)		$ (2)		$ (5)		$ (4)		$ (19)	$ (26)	$ (17)
[1]	The sum of quarterly information may not agree to year to date information due to rounding.

Income Taxes Income Taxes Effec

Income Taxes Income Taxes Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended																12 Months Ended
		Dec. 31, 2018		Sep. 30, 2018	[2]	Jun. 30, 2018	[2]	Mar. 31, 2018	[2]	Dec. 31, 2017	[2]	Sep. 30, 2017	[2]	Jun. 30, 2017	[2]	Mar. 31, 2017	[2]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount																		$ (145)	$ (165)	$ (131)
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount																		1	0	1
Tax adjustment related to REIT operations																		138	159	(121)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount																		(4)	(2)	(1)
Foreign Income Tax Expense (Benefit), Continuing Operations																		(9)	(3)	(7)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	[1]																	0	(15)	0
Benefit (provision) for income taxes		$ (5)	[2]	$ (5)		$ (5)		$ (4)		$ (15)		$ (2)		$ (5)		$ (4)		(19)	$ (26)	$ (17)
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount																		17
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax		$ 2																$ 2
[1]	Pursuant to the Tax Cuts and Jobs Act, which was signed into law in December 2017, the Company was required to write down its net federal deferred tax asset in the amount of $17 million as a result of the reduction in the federal corporate tax rate offset by a benefit of $2 million related to the refund of the Company's alternative minimum tax credit carryforward.
[2]	The sum of quarterly information may not agree to year to date information due to rounding.

Income Taxes (Components of Def

Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets, Gross		$ 20	$ 22
Property and equipment		5	5
Deferred site rental receivable		7	7
Deferred Tax Liabilities, Gross		12	12
Deferred Tax Assets, Goodwill and Intangible Assets		4	5
Net operating loss carryforwards	[1]	18	21
Deferred ground lease payable		2	2
Accrued liabilities		5	5
Other		3	1
Valuation allowance, asset		(1)	(1)
Total deferred income tax assets, net		31	33
Deferred Tax Assets, Net		19	21
Domestic Tax Authority [Member]
Deferred Tax Assets, Gross		25	25
Valuation allowance, asset		0	0
Deferred Tax Assets, Net		25	25
State and Local Jurisdiction [Member]
Deferred Tax Assets, Gross		1	1
Valuation allowance, asset		0	0
Deferred Tax Assets, Net		1	1
Foreign Tax Authority [Member]
Deferred Tax Assets, Gross		(6)	(4)
Valuation allowance, asset		(1)	(1)
Deferred Tax Liabilities, Net		$ 7	$ 5
[1]	Balance results from the Company's foreign NOLs. Due to the Company's REIT status, no federal or state NOLs result in the Company recording a deferred income tax asset. See further discussion surrounding the Company's NOL balances below.

Income Taxes (Jurisdictional Co

Income Taxes (Jurisdictional Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Income Taxes (Jurisdictional components of deferred taxes)
Deferred Tax Assets, Gross	$ 20	$ 22
Valuation allowance, asset	(1)	(1)
Net deferred income tax assets (liabilities)	19	21
U.S. Federal [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	1,500
Deferred Tax Assets, Gross	25	25
Valuation allowance, asset	0	0
Net deferred income tax assets (liabilities)	25	25
State and Local Jurisdiction [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	600
Deferred Tax Assets, Gross	1	1
Valuation allowance, asset	0	0
Net deferred income tax assets (liabilities)	1	1
Foreign Tax Authority [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	50
Deferred Tax Assets, Gross	(6)	(4)
Valuation allowance, asset	(1)	(1)
Deferred Tax Liabilities, Net	(7)	$ (5)
Stock Compensation Plan [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	$ 237

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2018
Preferred Stock, Liquidation Preference, Value	$ 1,650,000,000	$ 1,650,000,000
Purchases of common stock, value	34,000,000	23,000,000	$ 25,000,000
At the Market Stock Offering Program, aggregate value of common stock	750,000,000			$ 500,000,000
Life to Date Net Proceeds Under ATM				350,000,000
Availability Under ATM	750,000,000			$ 150,000,000
Net proceeds from issuance of preferred stock	$ 0	$ 1,608,000,000	$ 0
Minimum [Member]
Convertible Preferred Stock, Shares Issued upon Conversion	8.7260
Maximum [Member]
Convertible Preferred Stock, Shares Issued upon Conversion	10.4712
March 2018 Equity Financing [Member]
Stock Issued During Period, Shares, New Issues	8,000,000
Proceeds from Issuance of Common Stock	$ 841,000,000
Preferred Stock [Member]
Preferred Stock, Liquidation Preference, Value	$ 1,000
Preferred Stock, Redemption Date	Aug. 1, 2020
Preferred Stock, Dividend Rate, Percentage	6.875%
Preferred Stock [Member] | July 2017 Equity Offering [Member]
Stock Issued During Period, Shares, New Issues	1,650,000
Sale of Stock, Transaction Date	Jul. 26, 2017
Preferred Stock, Dividend Rate, Percentage	6.875%
Preferred Stock, Per Share Sales Price	$ 1,000
Net proceeds from issuance of preferred stock	$ 1,608,000,000
Common Stock [Member]
Stock Issued During Period, Shares, New Issues	8,000,000	44,000,000	15,000,000
Proceeds from Issuance of Common Stock			$ 0
Purchases of common stock, shares	300,000
Common Stock [Member] | March 2018 Equity Financing [Member]
Sale of Stock, Transaction Date	Mar. 1, 2018
Common Stock [Member] | May 2017 Equity Offering [Member]
Stock Issued During Period, Shares, New Issues	4,750,000
Proceeds from Issuance of Common Stock	$ 442,000,000
Sale of Stock, Transaction Date	May 1, 2017
Common Stock [Member] | July 2017 Equity Offering [Member]
Stock Issued During Period, Shares, New Issues	40,150,000
Proceeds from Issuance of Common Stock	$ 3,800,000,000
Sale of Stock, Transaction Date	Jul. 26, 2017

Stockholders' Equity Tax Treatm

Stockholders' Equity Tax Treatment of Dividends Paid (Details) - $ / shares		3 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid		$ 17.1875	$ 17.1875	$ 17.1875	$ 17.1875	$ 17.1875
Common Stock, Dividends, Per Share, Cash Paid		$ 1.125	$ 1.05	$ 1.05	$ 1.05
Preferred Stock [Member]
Class of Stock [Line Items]
Payment Date		Feb. 1, 2019	Nov. 1, 2018	Aug. 1, 2018	May 1, 2018	Feb. 1, 2018
Common Stock [Member]
Class of Stock [Line Items]
Payment Date		Dec. 31, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018
Common Stock [Member]
Class of Stock [Line Items]
Non-Taxable Distribution		$ 0.387	$ 0.361	$ 0.361	$ 0.361
Ordinary Taxable Dividend Per Share [Member]
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid			17.1875	17.1875	17.1875	$ 17.1875
Common Stock, Dividends, Per Share, Cash Paid		0.738	0.689	0.689	0.689
Qualified Taxable Dividend Per Share [Member]
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid	[1]		0.1269	0.1269	0.1269	0.1269
Common Stock, Dividends, Per Share, Cash Paid	[1]	0.005	0.005	0.005	0.005
Long-Term Capital Gain Distribution Per Share [Member]
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid			17.0606	17.0606	17.0606	$ 17.0606
Common Stock, Dividends, Per Share, Cash Paid		$ 0.733	$ 0.684	$ 0.684	$ 0.684
[1]	Qualified taxable dividend and section 199A dividend amounts are included in ordinary taxable dividend amounts.

Stockholders' Equity Declaratio

Stockholders' Equity Declaration and Payment of Dividends (Details) - USD ($) $ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Class of Stock [Line Items]

Dividends, Common Stock, Cash

$ 467

[1]

$ 438

[1]

$ 438

[1]

$ 439

[1]

$ (1,785)

$ (1,513)

$ (1,245)

Common Stock, Dividends, Per Share, Cash Paid

$ 1.125

$ 1.05

$ 1.05

$ 1.05

Preferred Stock, Dividends, Per Share, Cash Paid

$ 17.1875

$ 17.1875

$ 17.1875

$ 17.1875

$ 17.1875

Dividends, Preferred Stock, Cash

$ 28

$ 28

$ 28

$ 28

$ 28

Common Stock [Member]

Class of Stock [Line Items]

Dividends Payable, Date Declared

Oct. 15, 2018

Aug. 2, 2018

May 17, 2018

Feb. 21, 2018

Dividends Payable, Date of Record

Dec. 14, 2018

Sep. 14, 2018

Jun. 15, 2018

Mar. 16, 2018

Payment Date

Dec. 31, 2018

Sep. 28, 2018

Jun. 29, 2018

Mar. 30, 2018

Preferred Stock [Member]

Class of Stock [Line Items]

Dividends Payable, Date Declared

Dec. 11, 2018

Sep. 19, 2018

Jun. 22, 2018

Mar. 19, 2018

Dec. 15, 2017

Dividends Payable, Date of Record

Jan. 15, 2019

Oct. 15, 2018

Jul. 15, 2018

Apr. 15, 2018

Jan. 15, 2018

Payment Date

Feb. 1, 2019

Nov. 1, 2018

Aug. 1, 2018

May 1, 2018

Feb. 1, 2018

[1]

Inclusive of dividends accrued for holders of unvested RSUs, which will be paid when and if the RSUs vest

Stock-based Compensation (Narra

Stock-based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	10
Vesting Period	3 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	3
Shares granted, number of shares	1
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, weighted-average grant-date fair value (in dollars per share)	$ 91.52	$ 73.52	$ 68.53
Weighted-average requisite service period (years)	2 years 5 months
Restricted stock or unit expense	$ 90	$ 89	$ 76
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, number of shares	0.4
Time Vesting Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, number of shares	0.8
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 82
Period for recognition	1 year

Stock-based Compensation (Summa

Stock-based Compensation (Summary of Restricted Stock Awards Activity) (Details) - Restricted Stock Units (RSUs) [Member] shares in Millions	12 Months Ended
	Dec. 31, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(1)
Shares outstanding at the beginning of the year, number of shares	3
Shares outstanding at the end of year, number of shares	3
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	0

Stock-based Compensation (Sum_2

Stock-based Compensation (Summary of the Assumptions Used in the Monte Carlo Simulation to Determine the Grant-Date Fair Value) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation [Abstract]
Risk-free rate	2.40%	1.50%	0.90%
Expected volatility	18.00%	18.00%	19.00%
Expected dividend rate	3.80%	4.40%	4.20%

Stock-based Compensation (Sum_3

Stock-based Compensation (Summary of Restricted Stock Awards Vested) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares vested	1	0.7	0.8
Fair value on vesting date	$ 107	$ 67	$ 71

Stock-based Compensation (Stock

Stock-based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 108	$ 96	$ 97
Allocated Share-based Compensation Expense	108	96	97
Site Rental Cost of Operations [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	17	15	14
Network Services and Other Costs of Operations [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	8	5	8
Selling, General and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	83
Allocated Share-based Compensation Expense	$ 83	$ 76	$ 75

Commitments and Contingencies T

Commitments and Contingencies Tower purchase option (Details)	Dec. 31, 2018
Subject to Capital Lease with Sprint, TMO, or AT&T [Member]
Tower count as a percentage of total towers	53.00%

Leases (Details)

Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property Subject to or Available for Operating Lease [Line Items]
Percentage of wireless infrastructure that has non-cancelable operating leases	74.00%
Operating Leases, Owned Land Under Tower, Expiration Term	20 years
Operating Leases, Leased Land Under Tower, Expiration Term	10 years
Rental expense from operating leases	$ 751	$ 710	$ 678
Contingent rental payments	$ 108	$ 100	$ 97
Greater than 10 Years, Inclusive of Renewals at the Company's Option [Member]
Property Subject to or Available for Operating Lease [Line Items]
Percentage of site rental gross margin that is derived from towers where the lease for the land has a final expiration date	90.00%
Greater than 20 Years, Inclusive of Renewals at the Company's Option [Member]
Property Subject to or Available for Operating Lease [Line Items]
Percentage of site rental gross margin that is derived from towers where the lease for the land has a final expiration date	75.00%

Leases Operating Lease Expense

Leases Operating Lease Expense - 5 yr table (Details) $ in Millions	Dec. 31, 2018USD ($)
Operating Leases, Future Minimum Payments Due, 2019	$ 640
Operating Leases, Future Minimum Payments, Due 2020	631
Operating Leases, Future Minimum Payments, Due 2021	628
Operating Leases, Future Minimum Payments, Due 2022	623
Operating Leases, Future Minimum Payments, Due 2023	619
Operating Leases, Future Minimum Payments, Due Thereafter	8,054
Operating Leases, Future Minimum Payments Due	$ 11,195

Operating Segments and Concen_3

Operating Segments and Concentrations of Credit Risk (Major Customers) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Concentration Risk, Percentage	75.00%	86.00%	88.00%
AT&T [Member]
Concentration Risk, Percentage	20.00%	25.00%	27.00%
Sprint [Member]
Concentration Risk, Percentage	15.00%	17.00%	16.00%
Verizon Wireless [Member]
Concentration Risk, Percentage	20.00%	22.00%	22.00%
T-Mobile [Member]
Concentration Risk, Percentage	20.00%	22.00%	23.00%

Operating Segments and Concen_4

Operating Segments and Concentrations of Credit Risk Operating Segment Results (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)		Dec. 31, 2017USD ($)		Dec. 31, 2016USD ($)
Segment Reporting Information [Line Items]
Tower Count	40,000
Fiber Miles	65,000
Segment Site Rental Revenues	$ 4,716		$ 3,669		$ 3,233
Segment Services and Other Revenues	707		687		688
Segment Revenues	5,423		4,356		3,921
Segment Site Rental Cost of Operations	1,373		1,109		987
Segment Services and Other Cost of Operations	429		415		410
Segment Cost of Operations	1,802	[1],[2]	1,524	[3],[4]	1,397	[5],[6]
Segment site rental gross margin	3,343		2,560		2,246
Segment services and other gross margin	278		272		278
Segment General and Administrative Expenses	289	[2]	183	[4]	153	[6]
Segment Operating Profit	3,332		2,649		2,371
Allocated Share-based Compensation Expense	108		96		97
Depreciation, amortization and accretion	1,528		1,242		1,109
Interest expense and amortization of deferred financing costs	642		591		515
Other income (expenses) to reconcile to income (loss) before income taxes	173	[7]	82	[8]	133	[9]
Income (Loss) Before Income Taxes	690		471		374
Capital expenditures	1,741		1,228		874
Assets	32,785		32,229		22,675
Goodwill	10,078		10,021		5,758
Amortization of prepaid lease purchase price adjustments	20		20		22
Towers [Member]
Segment Reporting Information [Line Items]
Segment Site Rental Revenues	3,116		2,900		2,831
Segment Services and Other Revenues	691		637		604
Segment Revenues	3,807		3,537		3,435
Segment Site Rental Cost of Operations	848		845		840
Segment Services and Other Cost of Operations	418		374		345
Segment Cost of Operations	1,266	[1],[2]	1,219	[3],[4]	1,185	[5],[6]
Segment site rental gross margin	2,268		2,055		1,991
Segment services and other gross margin	273		263		259
Segment General and Administrative Expenses	110	[2]	94	[4]	93	[6]
Segment Operating Profit	2,431		2,224		2,157
Capital expenditures	442		418		430
Assets	17,667		17,941		18,395
Goodwill	5,127		5,127		5,115
Fiber [Member]
Segment Reporting Information [Line Items]
Segment Site Rental Revenues	1,600		769		402
Segment Services and Other Revenues	16		50		84
Segment Revenues	1,616		819		486
Segment Site Rental Cost of Operations	525		264		147
Segment Services and Other Cost of Operations	11		41		65
Segment Cost of Operations	536	[1],[2]	305	[3],[4]	212	[5],[6]
Segment site rental gross margin	1,075		505		255
Segment services and other gross margin	5		9		19
Segment General and Administrative Expenses	179	[2]	89	[4]	60	[6]
Segment Operating Profit	901		425		214
Capital expenditures	1,264		782		409
Assets	14,512		13,669		3,441
Goodwill	4,951		4,894		643
Other [Member]
Segment Reporting Information [Line Items]
Segment General and Administrative Expenses	191	[2]	167	[4]	143	[6]
Segment Operating Profit
Allocated Share-based Compensation Expense	108		96		97
Depreciation, amortization and accretion	1,528		1,242		1,109
Interest expense and amortization of deferred financing costs	642		591		515
Other income (expenses) to reconcile to income (loss) before income taxes	173	[7]	82	[8]	133	[9]
Capital expenditures	35		28		35
Assets	606		619		839
Goodwill	0		0		0
Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Allocated Share-based Compensation Expense	83		76		75
Cost of Sales [Member]
Segment Reporting Information [Line Items]
Allocated Share-based Compensation Expense	$ 25		$ 20		$ 22
[1]	Exclusive of depreciation, amortization and accretion shown separately
[2]	Segment cost of operations for the year ended December 31, 2018 excludes (1) stock-based compensation expense of $25 million and (2) prepaid lease purchase price adjustments of $20 million For the year ended December 31, 2018, Segment selling, general and administrative expenses exclude stock-based compensation expense of $83 million.
[3]	Exclusive of depreciation, amortization and accretion shown separately
[4]	Segment cost of operations for the year ended December 31, 2017 excludes (1) stock-based compensation expense of $20 million and (2) prepaid lease purchase price adjustments of $20 million. For the year ended December 31, 2017. Segment selling, general and administrative expenses exclude stock-based compensation expense of $76 million.
[5]	Exclusive of depreciation, amortization and accretion shown separately
[6]	Segment cost of operations for the year ended December 31, 2016 excludes (1) stock-based compensation expense of $22 million and (2) prepaid lease purchase price adjustments of $22 million. For the year ended December 31, 2016, Segment selling, general and administrative expenses exclude stock-based compensation expense of $75 million for the year ended .
[7]	See consolidated statement of operations for further information.
[8]	See consolidated statement of operations for further information.
[9]	See consolidated statement of operations for further information.

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Information [Line Items]
Cash and cash equivalents	$ 277	$ 314	$ 568
Restricted Cash. current	131	121	125
Restricted Cash, Noncurrent	5	5	5
Cash, Cash Equivalents and Restricted Cash	413	440	698
Interest paid	619	547	471
Income taxes paid (refund)	17	16	14
Increase (Decrease) in accounts payable for purchases of property and equipment	29	2	18
Purchase of property and equipment under capital leases and installment purchases	40	32	52
Preferred Stock Dividends Accrued but not Paid	$ 0	$ 28	$ 0

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017	[1]	Mar. 31, 2017	[1]	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Selected Quarterly Financial Information [Abstract]
Net Revenues	$ 1,419		$ 1,375		$ 1,330		$ 1,299		$ 1,238	[1]	$ 1,063	[1]	$ 1,038		$ 1,016		$ 5,423		$ 4,356		$ 3,921
Operating income (loss)	379		359		345		349		267	[1]	261	[1]	259		257		1,432		1,046		949
Gains (losses) on retirement of long-term obligations	0		(32)		(3)		(71)		0	[1]	0	[1]	0		(4)		(106)	[2]	(4)	[3]	(52)	[4]
Benefit (provision) for income taxes	(5)		(5)		(5)		(4)		(15)	[1]	(2)	[1]	(5)		(4)		$ (19)		$ (26)		$ (17)
Net income (loss) attributable to CCIC stockholders	$ 185		$ 136		$ 152		$ 86		$ 98		$ 115		$ 112		$ 119
Net income (loss) attributable to CCIC common stockholders, per common share:
Basic (in dollars per share)	$ 0.45		$ 0.33		$ 0.37		$ 0.21		$ 0.17	[1]	$ 0.22	[1]	$ 0.31		$ 0.33		$ 1.35		$ 1.01		$ 0.95
Diluted (in dollars per share)	$ 0.44		$ 0.33		$ 0.36		$ 0.21		$ 0.17	[1]	$ 0.21	[1]	$ 0.31		$ 0.33		$ 1.34		$ 1.01		$ 0.95
[1]	The sum of quarterly information may not agree to year to date information due to rounding.
[2]	Inclusive of the write off of the respective deferred financing costs.
[3]	The losses related to write off of deferred financing costs
[4]	Inclusive of the write off of the respective deferred financing costs.

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 11, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2012
Subsequent Event [Line Items]
Debt Instrument, Issuance Date							Oct. 1, 2012
Debt Instrument, Face Amount							$ 1,650
Debt Instrument, Interest Rate, Stated Percentage							5.25%
Debt Instrument Maturity Date Range							Jan. 1, 2023
Common Stock, Dividends, Per Share, Cash Paid		$ 1.125	$ 1.05	$ 1.05	$ 1.05
Dividend Declared [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Dividends Payable, Date Declared						Feb. 21, 2019
Dividends Payable, Date to be Paid						Mar. 29, 2019
Dividends Payable, Date of Record						Mar. 15, 2019
Paid subsequent to year end [Member]
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Cash Paid		$ 1.125
Debt [Member] | February 2019 Senior Notes [Domain] | High Yield Bonds [Member]
Subsequent Event [Line Items]
Debt Instrument, Issuance Date	Feb. 11, 2019
Debt Instrument, Face Amount	$ 1,000
Debt [Member] | February 2019 Senior Unsecured 4.300% Notes [Member] | High Yield Bonds [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 600
Debt Instrument, Interest Rate, Stated Percentage	4.30%
Debt Instrument Maturity Date Range	Feb. 1, 2029
Debt [Member] | February 2019 Senior Unsecured 5.200% Notes [Member] | High Yield Bonds [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 400
Debt Instrument, Interest Rate, Stated Percentage	5.20%
Debt Instrument Maturity Date Range	Feb. 1, 2049

Schedule II - Valuation and Q_3

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year		$ 14	$ 11		$ 10
Charged to operations		4	4		5
Credited to operations		(4)	(5)		(4)
Effect of exchange rate changes or Other adjustments		0	0		0
Valuation allowance and reserves, other adjustments		0	4	[1]	0
Balance at end of year		14	14		11
Deferred Tax Valuation Allowance [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year		1	7		2
Charged to operations		0	0		1
Credited to operations		0	0		0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Addition, Recovery		0	(6)		(2)
Effect of exchange rate changes or Other adjustments		0	0		0
Valuation allowance and reserves, other adjustments	[2]	0	0		6
Balance at end of year		$ 1	$ 1		$ 7
[1]	Represents the allowance for doubtful accounts reflected in the preliminary purchase price allocations for the 2017 Acquisitions. See note 3.
[2]	Inclusive of (1) the effects of acquisitions and (2) the inclusion of small cells in the REIT in January 2016.

Schedule III - Schedule of Re_3

Schedule III - Schedule of Real Estate and Depreciation (Details) $ in Millions		12 Months Ended
		Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Tower Count		40,000
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Amount of Encumbrances	[1]	$ 3,311
Gross Amount of Accumulated Depreciation Carried		(8,341)	$ (7,303)	$ (6,446)
Depreciation		(1,057)	(890)
Amount of Accumulated Depreciation Sold or Disposed		18	26
Other Deductions to Accumulated Depreciation		1	7
Real Estate Period Deductions to Accumulated Depreciation		19	33
Gross Amount of Property Carried		21,866	20,110	$ 16,121
Other Acquisitions	[2],[3]	5	2,788
Wireless Infrastructure Construction and Improvements		1,567	1,063
Purchase of land interests		56	81
Sustaining Capital Expenditures		85	56
Other Additions	[4]	64	46
Total Additions		1,777	4,034
Cost of Real Estate Sold or Disposed		$ (21)	$ (45)
Fiber Miles		65,000
[1]	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]	Includes acquisitions of communications infrastructure.
[3]	Inclusive of changes between the final purchase price allocation and the preliminary purchase price allocations.
[4]	Predominately relates to the purchase of property and equipment under capital leases and installment land purchases.