Crown Castle (CCI) 10-Q 6 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 03, 2018	Dec. 31, 2017
Entity Information [Line Items]
Common Stock, Shares, Outstanding	415,000,000		406,000,000
Entity Voluntary Filers	No
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-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		414,839,956
Entity Current Reporting Status	Yes

Condensed Consolidated Balance

Condensed Consolidated Balance Sheet - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 206	$ 314
Restricted cash	125	121
Receivables, net	455	398
Prepaid expenses	197	162
Other current assets	181	139
Total current assets	1,164	1,134
Deferred site rental receivables	1,303	1,300
Property and equipment, net	13,218	12,933
Goodwill	10,075	10,021
Other intangible assets, net	5,729	5,962
Long-term prepaid rent and other assets, net	885	879
Total assets	32,374	32,229
LIABILITIES AND EQUITY
Accounts payable	272	249
Accrued interest	154	132
Deferred revenues	476	457
Other accrued liabilities	272	339
Current maturities of debt and other obligations	112	115
Total current liabilities	1,286	1,292
Debt and other long-term obligations	15,844	16,044
Deferred credits and other liabilities	2,678	2,554
Total liabilities	19,808	19,890
Commitments and contingencies
CCIC stockholders' equity:
Common stock	4	4
Preferred Stock	0	0
Additional paid-in capital	17,711	16,844
Accumulated other comprehensive income (loss)	(5)	(4)
Dividends/distributions in excess of earnings	(5,144)	(4,505)
Total equity	12,566	12,339
Total liabilities and equity	$ 32,374	$ 32,229

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheet (Parenthetical) - USD ($) shares in Millions, $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Accumulated depreciation, property and equipment	$ 8,023	$ 7,500
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20	20
Preferred Stock, Shares Issued	2	2
Preferred Stock, Shares Outstanding	2	2
Preferred Stock, Liquidation Preference, Value	$ 1,650	$ 1,650
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	600	600
Common stock, shares outstanding	415	406

Condensed Consolidated Statemen

Condensed Consolidated Statement of Operations and Comprehensive Income (Loss) - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net revenues:
Site rental		$ 1,169	$ 869	$ 2,323	$ 1,726
Network services and other		161	169	307	328
Net revenues		1,330	1,038	2,630	2,054
Operating expenses:
Site rental	[1]	355	269	702	534
Network services and other	[1]	99	104	185	203
General and administrative		138	98	273	199
Asset write-down charges		6	4	9	5
Acquisition and integration costs		8	8	14	14
Depreciation, amortization and accretion		379	296	753	584
Total operating expenses		985	779	1,936	1,539
Operating income (loss)		345	259	694	515
Nonoperating Income (Expense) [Abstract]
Interest expense and amortization of deferred financing costs		(158)	(142)	(318)	(276)
Gains (losses) on retirement of long-term obligations		(3)	0	(74)	(4)
Interest income		1	1	2	1
Other income (expense)		0	(1)	(1)	4
Income (loss) before income taxes		185	117	303	240
Benefit (provision) for income taxes		(5)	(5)	(9)	(9)
Net income (loss) attributable to CCIC stockholders		180	112	294	231
Dividends on preferred stock		(28)	0	(57)	0
Net income (loss) attributable to CCIC common stockholders		152	112	237	231
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments		(1)	1	(1)	1
Total other comprehensive income (loss)		(1)	1	(1)	1
Comprehensive income (loss) attributable to CCIC stockholders		$ 179	$ 113	$ 293	$ 232
Net income (loss) attributable to CCIC common stockholders, per common share:
Basic		$ 0.37	$ 0.31	$ 0.58	$ 0.64
Diluted		$ 0.36	$ 0.31	$ 0.57	$ 0.64
Weighted-average common shares outstanding (in millions):
Basic		415	364	412	363
Diluted		416	366	413	364
Common Stock, Dividends, Per Share, Declared		$ 1.05	$ 0.95	$ 2.10	$ 1.90
[1]	Exclusive of depreciation, amortization and accretion shown separately.

Condensed Consolidated Stateme5

Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
Cash and Cash Equivalents at Beginning of Period	[1]	$ 440	$ 697
Cash and Cash Equivalents at End of Period	[1]	336	323
Cash flows from operating activities:
Net income (loss)		294	231
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Depreciation, amortization and accretion		753	584
(Gains) losses on retirement of long-term obligations		74	4
Amortization of deferred financing costs and other non-cash interest		4	5
Stock-based compensation expense		47	45
Asset write-down charges		9	5
Deferred income tax (benefit) provision		1	0
Other non-cash adjustments		1	(3)
Changes in assets and liabilities, excluding the effects of acquisitions:
Increase (decrease) in accrued interest		22	11
Increase (decrease) in accounts payable		3	(17)
Increase (decrease) in deferred revenues, deferred ground lease payables, other accrued liabilities and other liabilities		53	23
Decrease (increase) in receivables		(59)	91
Decrease (increase) in prepaid expenses, deferred site rental receivables, long-term prepaid rent and other assets		(91)	(48)
Net cash provided by (used for) operating activities		1,111	931
Cash flows from investing activities:
Payment for acquisitions of businesses, net of cash acquired		(18)	(2,104)
Capital expenditures		(763)	(563)
Other investing activities, net		3	(8)
Net cash provided by (used for) investing activities		(778)	(2,675)
Cash flows from financing activities:
Proceeds from issuance of long-term debt		1,743	1,345
Principal payments on long-term debt and other long-term obligations		(47)	(60)
Purchases and redemptions of long-term debt		(1,318)	0
Borrowings under revolving credit facility		485	1,755
Payments under revolving credit facility		(1,150)	(1,405)
Payments for financing costs		(20)	(11)
Proceeds from Issuance of Common Stock		841	464
Purchases of capital stock		(34)	(23)
Dividends/distributions paid on common stock		(879)	(696)
Dividends/distributions paid on preferred stock		(57)	0
Net cash provided by (used for) financing activities		(436)	1,369
Net increase (decrease) in cash, cash equivalents, and restricted cash		(103)	(375)
Effect of Exchange Rate on Cash and Cash Equivalents [Abstract]
Effect of exchange rate changes on cash		$ (1)	$ 1
[1]	See "Recently Adopted Accounting Pronouncements" in note 2 to the condensed consolidated financial statements for a discussion of recently adopted restricted cash guidance, which impacted certain presentations on the condensed consolidated statement of cash flows.

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Equity - USD ($) shares in Millions, $ in Millions	Total	Stockholders' Equity, Total [Member]		Common Stock [Member]	6.875% Convertible Preferred Stock	Additional Paid-in Capital [Member]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]		Dividends/Distributions in Excess of Earnings [Member]
Balance, shares Period Start at Dec. 31, 2016				361
Balance, value Period Start at Dec. 31, 2016		$ 7,557		$ 4	$ 0	$ 10,938	$ (6)		$ (3,379)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2016					0
Stock-based compensation related activity, net of forfeitures, value		53		$ 0		53	0		0
Stock-based compensation related activity, net of forfeitures, shares				1
Purchases and retirement of common stock, value		(23)		$ 0		(23)	0		0
Stock Issued During Period, Shares, New Issues				4
Stock Issued During Period, Value, New Issues		(464)		$ 0		(464)
Proceeds from Issuance of Common Stock	$ 464
Purchases and retirement of common stock, shares				0
Other comprehensive income (loss)	1	1	[1]	$ 0		0	1	[1]	0
Common stock dividends/distributions		(693)							(693)
Preferred stock dividends	0
Net income (loss)	231	231		$ 0		0	0		231
Balance, shares Period End at Jun. 30, 2017				366
Balance, value Period End at Jun. 30, 2017		7,590		$ 4	$ 0	11,432	(5)		(3,841)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2017					0
Balance, shares Period Start at Mar. 31, 2017				361
Balance, value Period Start at Mar. 31, 2017		7,363		$ 4	$ 0	10,968	(6)		(3,603)
Preferred Stock, Shares Outstanding Period Start at Mar. 31, 2017					0
Stock-based compensation related activity, net of forfeitures, value		23		$ 0		23	0		0
Stock-based compensation related activity, net of forfeitures, shares				0
Purchases and retirement of common stock, value		(1)		$ 0		(1)	0		0
Stock Issued During Period, Shares, New Issues				5
Stock Issued During Period, Value, New Issues		442		$ 0		(442)
Purchases and retirement of common stock, shares				0
Other comprehensive income (loss)	1	1	[1]	$ 0		0	1	[1]	0
Common stock dividends/distributions		(350)							(350)
Preferred stock dividends	0
Net income (loss)	$ 112	112		$ 0		0	0		112
Balance, shares Period End at Jun. 30, 2017				366
Balance, value Period End at Jun. 30, 2017		7,590		$ 4	$ 0	11,432	(5)		(3,841)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2017					0
Balance, shares Period Start at Dec. 31, 2017	406			406
Balance, value Period Start at Dec. 31, 2017	$ 12,339	12,339		$ 4	$ 0	16,844	(4)		(4,505)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2017	2				2
Balance, shares Period End at Mar. 31, 2018				415
Balance, value Period End at Mar. 31, 2018		12,832		$ 4	$ 0	17,690	(4)		(4,858)
Preferred Stock, Shares Outstanding Period End at Mar. 31, 2018					2
Balance, shares Period Start at Dec. 31, 2017	406			406
Balance, value Period Start at Dec. 31, 2017	$ 12,339	12,339		$ 4	$ 0	16,844	(4)		(4,505)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2017	2				2
Stock-based compensation related activity, net of forfeitures, value		60		$ 0		60	0		0
Stock-based compensation related activity, net of forfeitures, shares				1
Purchases and retirement of common stock, value		(34)		$ 0		(34)	0		0
Stock Issued During Period, Shares, New Issues				8
Stock Issued During Period, Value, New Issues		841		$ 0		(841)
Proceeds from Issuance of Common Stock	$ 841
Purchases and retirement of common stock, shares				0
Other comprehensive income (loss)	(1)	(1)		$ 0		0	(1)		0
Common stock dividends/distributions		876							876
Preferred stock dividends	(57)	(57)							(57)
Net income (loss)	$ 294	294		$ 0		0	0		294
Balance, shares Period End at Jun. 30, 2018	415			415
Balance, value Period End at Jun. 30, 2018	$ 12,566	12,566		$ 4	$ 0	17,711	(5)		(5,144)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2018	2				2
Balance, shares Period Start at Mar. 31, 2018				415
Balance, value Period Start at Mar. 31, 2018		12,832		$ 4	$ 0	17,690	(4)		(4,858)
Preferred Stock, Shares Outstanding Period Start at Mar. 31, 2018					2
Stock-based compensation related activity, net of forfeitures, value		24		$ 0		24	0		0
Stock-based compensation related activity, net of forfeitures, shares				0
Purchases and retirement of common stock, value		(1)		$ 0		(1)	0		0
Stock Issued During Period, Shares, New Issues				0
Proceeds from Issuance of Common Stock		(2)		$ 0		(2)
Purchases and retirement of common stock, shares				0
Other comprehensive income (loss)	$ (1)	(1)	[1]	$ 0		0	(1)	[1]	0
Common stock dividends/distributions		(438)							(438)
Preferred stock dividends	(28)	(28)							(28)
Net income (loss)	$ 180	180		$ 0		0	0		180
Balance, shares Period End at Jun. 30, 2018	415			415
Balance, value Period End at Jun. 30, 2018	$ 12,566	$ 12,566		$ 4	$ 0	$ 17,711	$ (5)		$ (5,144)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2018	2				2
[1]	See the condensed statement of operations and other comprehensive income (loss) for the components of "other comprehensive income (loss)."

General

General	6 Months Ended
	Jun. 30, 2018
General
General	General The information contained in the following notes to the consolidated financial statements is condensed from that which would appear in the annual consolidated financial statements; accordingly, the consolidated financial statements included herein should be reviewed in conjunction with the consolidated financial statements for the fiscal year ended December 31, 2017 , and related notes thereto, included in the 2017 Form 10-K filed by Crown Castle International Corp. ("CCIC") with the SEC. Capitalized terms used but not defined in these notes to the condensed consolidated financial statements have the same meaning given to them in our 2017 Form 10-K. References to the "Company" include CCIC and its predecessor, as applicable, and their subsidiaries, unless otherwise indicated or the context indicates otherwise. 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"). The Company's operating segments consist of (1) Towers and (2) Fiber. See note 11 . As part of the Company's effort to provide comprehensive communications infrastructure solutions, the Company offers certain network services relating to its communications infrastructure, consisting of (1) site development services primarily relating to existing or new tenant equipment installations on its towers and small cells, 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 Company operates as a REIT for U.S. federal income tax purposes. In addition, the Company has certain taxable REIT subsidiaries ("TRSs"). See note 7 . Approximately 53% of the Company's towers are leased or subleased or operated and managed under master leases, subleases, and 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. Basis of Presentation The condensed consolidated financial statements included herein are unaudited; however, they include all adjustments (consisting only of normal recurring adjustments) which, in the opinion of management, are necessary to state fairly the consolidated financial position of the Company at June 30, 2018 , and the consolidated results of operations and the consolidated cash flows for the six months ended June 30, 2018 and 2017 . The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The results of operations for the interim periods presented are not necessarily indicative of the results to be expected for the full year. The preparation of financial statements in conformity with 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	6 Months Ended
	Jun. 30, 2018
Summary of Significant Accounting Policies [Abstract]
Significant Accounting Policies	Summary of Significant Accounting Policies The significant accounting policies used in the preparation of the Company's condensed consolidated financial statements are disclosed in the 2017 Form 10-K, other than as updated by certain recent accounting pronouncements described below. 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 customers, the Company’s pattern of revenue recognition is 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 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 condensed consolidated statement of cash flows and certain disclosures. See note 12 . 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 condensed 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 is effective for the Company as of January 1, 2019. This guidance is required to be applied, at the Company's election, either using a (1) modified retrospective approach for all leases existing at, or entered into after, the beginning of the earliest comparative period presented, or (2) cumulative-effect approach for all leases existing at, or entered into, after the effective date. The Company expects to apply the guidance using the cumulative-effect approach, thereby applying the new guidance at the effective date, without adjusting the comparative periods and, if necessary, recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Although early adoption is permitted, the Company will not adopt the new guidance prior to January 1, 2019. With regard to the application of this guidance to the Towers segment, the Company expects that (1) its Towers lessee arrangements will continue to be classified as operating leases under the new guidance; (2) this guidance will have a material impact on its condensed consolidated balance sheet due to the addition of right-of-use assets and lease liabilities for lessee arrangements (which primarily consist of ground leases under the Company's towers); and (3) there will not be a material impact to its condensed consolidated statement of operations and condensed consolidated statement of cash flows. The Company is in the process of updating certain of its existing information technology systems to integrate the new guidance requirement with respect to its Tower segment. With regard to the application of this guidance to the Fiber segment, the Company (1) has established and is progressing through the various steps of a cross-functional project plan to assess the impact of the standard; (2) expects this guidance to have a material impact on its condensed consolidated balance sheet due to the addition of right-of-use assets and lease liabilities for lessee arrangements (which primarily consist of fiber-related leases); and (3) continues to assess additional impacts to its condensed consolidated financial statements, including the condensed consolidated statement of operations and the condensed consolidated statement of cash flows.

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2018
Acquisitions [Abstract]
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	Acquisitions 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 owned or had 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. The preliminary purchase price allocation for the Lightower Acquisition is shown below and is based upon a preliminary valuation which is subject to change as the Company obtains additional information with respect to fixed assets, intangible assets and certain liabilities. Preliminary Purchase Price Allocation Current assets $ 99 Property and equipment 2,194 Goodwill (a) 3,168 Other intangible assets, net (b) 2,177 Other non-current assets 30 Current liabilities (174 ) Other non-current liabilities (342 ) Net assets acquired (c) $ 7,152 (a) The preliminary 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) Predominately comprised of site rental contracts and customer 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.

Revenues (Notes)

Revenues (Notes)	6 Months Ended
	Jun. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenues Site rental revenues The Company generates site rental revenues from its core business by providing customers 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 from the Company’s contracts are recognized on a straight-line, monthly basis over the fixed, non-cancelable term of the relevant contract, which generally ranges from five to 15 years for wireless customers and three to 20 years related to the Company's fiber solutions (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 a 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). 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. The Company's assets related to straight-line site rental revenues include current amounts of $121 million included in "other current assets" and non-current amounts of $1.3 billion included in "deferred site rental receivables" for the period ended June 30, 2018 . 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 condensed consolidated balance sheet. Network services and other revenues As part of the Company’s effort to provide comprehensive communications infrastructure solutions, the Company offers certain network services, primarily relating to its towers and small cells, predominately consisting of (1) site development services and (2) installation services. Under network service agreements, the Company may have multiple performance obligations for site development services, which primarily include: structural analysis, zoning, permitting and construction drawings. Upon contract commencement, the Company assesses services to customers and identifies performance obligations for each promise to provide a distinct service. 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. For each of the above performance obligations, network 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 customer. 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. Payments generally are due within 45 days and generally do not contain variable-consideration provisions. Since performance obligations are typically satisfied prior to receiving payment from customers, the unconditional right to payment is recorded within "receivables, net" on the Company’s condensed consolidated balance sheet. The Company has one performance obligation for installation services, which is satisfied at the time of the respective installation or augmentation. This single performance obligation is typically completed in advance of receipt of payment from customers, and therefore the unconditional right to payment is recorded within “receivables, net” on the Company’s condensed consolidated balance sheet. The vast majority of the Company’s network services relates to the Company’s Towers operating segment, and generally have a duration of one year or less. Additional information on revenues As of January 1, 2018 and June 30, 2018 , $2.1 billion and $2.2 billion of unrecognized revenue, respectively, was reported in "deferred revenues" and "other non-current liabilities" on our condensed consolidated balance sheet. During the six months ended June 30, 2018, approximately $200 million of the January 1, 2018 unrecognized revenue balance was recognized as revenue. The following table is a summary of the contracted amounts owed to the Company by customers pursuant to site rental contracts in effect as of June 30, 2018 . Six months ending December 31, Years ending December 31, 2018 2019 2020 2021 2022 Thereafter Total Contracted amounts (a) $ 2,039 $ 3,829 $ 3,552 $ 3,279 $ 3,054 $ 6,928 $ 22,681 (a) Excludes amounts related to network services, as those contracts generally have a duration of one year or less. See note 11 for further information regarding the Company's operating segments.

Debt and Other Obligations

Debt and Other Obligations	6 Months Ended
	Jun. 30, 2018
Debt and Other Obligations [Abstract]
Debt and Other Obligations	Debt and Other Obligations Original Issue Date Contractual Maturity Date (a) Balance as of June 30, 2018 Balance as of December 31, 2017 Stated Interest Rate as of June 30, 2018 (a) Bank debt - variable rate: 2016 Revolver Jan. 2016 Jun. 2023 (e) $ 315 (b)(d)(e) $ 980 3.4 % (e) 2016 Term Loan A Jan. 2016 Jun. 2023 (e) 2,383 2,397 3.3 % (e) Total bank debt 2,698 3,377 Securitized debt - fixed rate: Secured Notes, Series 2009-1, Class A-1 July 2009 Aug. 2019 22 32 6.3 % Secured Notes, Series 2009-1, Class A-2 July 2009 Aug. 2029 70 70 9.0 % Tower Revenue Notes, Series 2010-3 Jan. 2010 Jan. 2040 (c) — (d) 1,246 N/A Tower Revenue Notes, Series 2010-6 Aug. 2010 Aug. 2040 (c) (f) 996 995 4.9 % Tower Revenue Notes, Series 2015-1 May 2015 May 2042 (c) 298 297 3.2 % Tower Revenue Notes, Series 2015-2 May 2015 May 2045 (c) 693 692 3.7 % Total securitized debt 2,079 3,332 Bonds - fixed rate: 5.250% Senior Notes Oct. 2012 Jan. 2023 1,640 1,639 5.3 % 3.849% Secured Notes Dec. 2012 Apr. 2023 993 993 3.9 % 4.875% Senior Notes Apr. 2014 Apr. 2022 843 842 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 743 743 3.7 % 2.250% Senior Notes Sept. 2016 Sept. 2021 696 695 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 742 742 3.2 % 3.650% Senior Notes Aug. 2017 Sept. 2027 991 991 3.7 % 3.150% Senior Notes Jan. 2018 Jul. 2023 742 (d) — 3.2 % 3.800% Senior Notes Jan. 2018 Feb. 2028 988 (d) — 3.8 % Total bonds 10,957 9,223 Other: Capital leases and other obligations Various Various 222 227 Various Total debt and other obligations 15,956 16,159 Less: current maturities and short-term debt and other current obligations 112 115 Non-current portion of long-term debt and other long-term obligations $ 15,844 $ 16,044 (a) See the 2017 Form 10-K, including note 8, for additional information regarding the maturity and principal amortization provisions and interest rates relating to the Company's indebtedness. (b) As of June 30, 2018 , the undrawn availability under the 2016 Revolver was $ 3.9 billion . (c) If the respective series of such debt is not paid in full on or prior to an applicable 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 additional interest (of an additional approximately 5% per annum) will accrue on the respective series. See the 2017 Form 10-K for additional information regarding these provisions. (d) In January 2018 , the Company issued $750 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 ("3.15% Senior Notes") and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028 ("3.80% Senior Notes") (collectively, "January 2018 Senior Notes Offering"). 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. (e) In June 2018 , the Company entered into an amendment to the Credit Facility to (1) increase commitments on the 2016 Revolver by $750 million ,for total 2016 Revolver commitments of $4.25 billion , and (2) extend the maturity of the Credit Facility from August 2022 to June 2023 . Additionally, pursuant to this amendment and with regards to the Credit Facility, the Company is obligated to pay (1) interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.00% to 1.75%, and (2) commitment fees ranging from 0.125% and 0.35%, each of which is based on the Company's senior unsecured debt rating. (f) See note 13 for more information regarding the Company's July 2018 Tower Revenue Notes (as defined in note 13). Contractual Maturities The following are the scheduled contractual maturities of the total debt and other long-term obligations of the Company outstanding as of June 30, 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. Six Months Ending December 31, Years Ending December 31, Unamortized Adjustments, Net Total Debt and Other Obligations Outstanding 2018 2019 2020 2021 2022 Thereafter Total Cash Obligations Scheduled contractual maturities $ 56 $ 105 $ 137 $ 1,699 $ 1,085 $ 12,984 $ 16,066 $ (110 ) $ 15,956 Purchases and Redemptions of Long-Term Debt The following is a summary of purchases and redemptions of long-term debt during the six months ended June 30, 2018 . Principal Amount Cash Paid (a) Gains (Losses) January 2010 Tower Revenue Notes $ 1,250 $ 1,318 $ (71 ) (b) 2016 Term Loan A $ — $ — $ (3 ) (b) Total $ 1,250 $ 1,318 $ (74 ) (a) Exclusive of accrued interest. (b) Inclusive of the write off of respective deferred financing costs. See note 13. Interest Expense and Amortization of Deferred Financing Costs The components of interest expense and amortization of deferred financing costs are as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Interest expense on debt obligations $ 157 $ 139 $ 314 $ 271 Amortization of deferred financing costs and adjustments on long-term debt 5 5 11 9 Other, net of capitalized interest (4 ) (2 ) (7 ) (4 ) Total $ 158 $ 142 $ 318 $ 276

Fair Value Disclosures

Fair Value Disclosures	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures
Fair Value Disclosures	Fair Value Disclosures Level in Fair Value Hierarchy June 30, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Assets: Cash and cash equivalents 1 $ 206 $ 206 $ 314 $ 314 Restricted cash, current and non-current 1 130 130 126 126 Liabilities: Total debt and other obligations 2 15,956 15,911 16,159 16,644 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, non-binding quotes from brokers. Quotes from brokers require judgment and are based on the brokers' interpretation of market information, including implied credit spreads for similar borrowings on recent trades or bid/ask prices or quotes from active markets if available. There were no changes since December 31, 2017 in the Company's valuation techniques used to measure fair values.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
Income Taxes
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 net 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, to maintain qualification for taxation as a REIT. The Company's 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 the six months ended June 30, 2018 and 2017 , the Company's effective tax rate differed from the federal statutory rate predominately due to the Company's REIT status, including the dividends paid deduction.

Per Share Information

Per Share Information	6 Months Ended
	Jun. 30, 2018
Per Share Information
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 three and six months ended June 30, 2018 , 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 restricted stock units as determined under the treasury stock method and (2) conversion of the Company's 6.875% Mandatory Convertible Preferred Stock (as defined in note 10 ), as determined under the if-converted method. For the three and six months ended June 30, 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 the vesting of restricted stock units as determined under the treasury stock method. Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Net income (loss) attributable to CCIC stockholders $ 180 $ 112 $ 294 $ 231 Dividends on preferred stock (28 ) — (57 ) — Net income (loss) attributable to CCIC common stockholders for basic and diluted computations $ 152 $ 112 $ 237 $ 231 Weighted-average number of common shares outstanding (in millions): Basic weighted-average number of common stock outstanding 415 364 412 363 Effect of assumed dilution from potential issuance of common shares relating to restricted stock units 1 2 1 1 Diluted weighted-average number of common shares outstanding 416 366 413 364 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 0.37 $ 0.31 $ 0.58 $ 0.64 Diluted $ 0.36 $ 0.31 $ 0.57 $ 0.64 During the six months ended June 30, 2018 , the Company granted one million restricted stock units. For both the three and six months ended June 30, 2018 , 16 million common share equivalents related to the 6.875% Mandatory Convertible Preferred Stock were excluded from the dilutive common shares because the impact of such conversion would be anti-dilutive, based on the Company's common stock price as of June 30, 2018 .

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure
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. In addition, the Company has the option to purchase approximately 53% of the Company's towers at the end of their respective lease terms. The Company has no obligation to exercise such purchase options.

Equity

Equity	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	Equity Declaration and Payment of Dividends During the six months ended June 30, 2018 , the following dividends were declared or paid: Equity Type Declaration Date Record Date Payment Date Dividends Per Share Aggregate Payment Amount 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) 6.875% Mandatory Convertible Preferred Stock December 15, 2017 January 15, 2018 February 1, 2018 $ 17.1875 $ 28 6.875% Mandatory Convertible Preferred Stock March 19, 2018 April 15, 2018 May 1, 2018 $ 17.1875 $ 28 6.875% Mandatory Convertible Preferred Stock June 22, 2018 July 15, 2018 August 1, 2018 $ 17.1875 $ 28 (a) Inclusive of dividends accrued for holders of unvested restricted stock units, which will be paid when and if the restricted stock units vest. See note 13. Purchases of the Company's Common Stock For the six months ended June 30, 2018 , the Company purchased 0.3 million shares of its common stock utilizing $34 million in cash. The common stock shares purchased relate to shares withheld in connection with the payment of withholding taxes upon vesting of restricted stock units. 2015 "At the Market" Stock Offering Program The Company previously maintained an "at the market" stock offering program ("2015 ATM 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. The Company sold shares of its common stock under the 2015 ATM Program generating aggregate gross proceeds of approximately $350 million . The Company terminated its previously outstanding 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 ("2018 ATM Program") through which it may issue and sell shares of its common stock having an aggregate gross sales price of up to $750 million . 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 may include the funding of future acquisitions or investments and the repayment or repurchase of any outstanding indebtedness. The Company has not sold any shares of common stock under the 2018 ATM Program. March 2018 Equity Financing 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.

Operating Segments

Operating Segments	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	Operating Segments The Company's operating segments are (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 network 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 60,000 route miles of fiber primarily supporting small cell networks and fiber solutions. The measurements of profit or loss used by the Company's chief operating decision maker to evaluate the results of operations of its operating segments are (1) segment site rental gross margin, (2) segment network 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 network services and other gross margin as segment network services and other revenues less segment network 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 network services and other gross margin, less 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. Three Months Ended June 30, 2018 Three Months Ended June 30, 2017 Towers Fiber Other Consolidated Total Towers Fiber Other Consolidated Total Segment site rental revenues $ 771 $ 398 $ 1,169 $ 718 $ 151 $ 869 Segment network services and other revenues 158 3 161 158 11 169 Segment revenues 929 401 1,330 876 162 1,038 Segment site rental cost of operations 216 130 346 211 52 263 Segment network services and other cost of operations 94 3 97 96 8 104 Segment cost of operations (a)(b) 310 133 443 307 60 367 Segment site rental gross margin 555 268 823 507 99 606 Segment network services and other gross margin 64 — 64 62 3 65 Segment general and administrative expenses (b) 27 44 71 23 19 42 Segment operating profit (loss) 592 224 816 546 83 629 Other general and administrative expenses (b) $ 47 47 $ 41 41 Stock-based compensation expense 26 26 17 17 Depreciation, amortization and accretion 379 379 296 296 Interest expense and amortization of deferred financing costs 158 158 142 142 Other income (expenses) to reconcile to income (loss) before income taxes (c) 21 21 16 16 Income (loss) before income taxes $ 185 $ 117 Capital expenditures $ 98 $ 289 $ 6 $ 393 $ 107 $ 188 $ 6 $ 301 Total assets (at period end) $ 17,780 $ 14,100 $ 494 $ 32,374 $ 18,208 $ 5,811 $ 465 $ 24,484 (a) Exclusive of depreciation, amortization and accretion shown separately. (b) Segment cost of operations excludes (1) stock-based compensation expense of $6 million and $2 million for the three months ended June 30, 2018 and 2017 , respectively, and (2) prepaid lease purchase price adjustments of $5 million for both of the three months ended June 30, 2018 and 2017 . General and administrative expenses exclude stock-based compensation expense of $20 million and $15 million for the three months ended June 30, 2018 and 2017 , respectively. (c) See condensed consolidated statement of operations for further information. Six Months Ended June 30, 2018 Six Months Ended June 30, 2017 Towers Fiber Other Consolidated Total Towers Fiber Other Consolidated Total Segment site rental revenues $ 1,536 $ 787 $ 2,323 $ 1,434 $ 292 $ 1,726 Segment network services and other revenues 300 7 307 308 20 328 Segment revenues 1,836 794 2,630 1,742 312 2,054 Segment site rental cost of operations 427 256 683 420 99 519 Segment network services and other cost of operations 176 5 181 185 17 202 Segment cost of operations (a)(b) 603 261 864 605 116 721 Segment site rental gross margin 1,109 531 1,640 1,014 193 1,207 Segment network services and other gross margin 124 2 126 123 3 126 Segment general and administrative expenses (b) 53 87 140 47 36 83 Segment operating profit (loss) 1,180 446 1,626 1,090 160 1,250 Other general and administrative expenses (b) $ 94 94 $ 80 80 Stock-based compensation expense 52 52 42 42 Depreciation, amortization and accretion 753 753 584 584 Interest expense and amortization of deferred financing costs 318 318 276 276 Other income (expenses) to reconcile to income (loss) before income taxes (c) 106 106 28 28 Income (loss) before income taxes $ 303 $ 240 Capital expenditures $ 195 $ 552 $ 16 $ 763 $ 208 $ 342 $ 13 $ 563 (a) Exclusive of depreciation, amortization and accretion shown separately. (b) Segment cost of operations excludes (1) stock-based compensation expense of $13 million and $ 6 million for the six months ended June 30, 2018 and 2017, respectively, and (2) prepaid lease purchase price adjustments of $10 million for both of the six months ended June 30, 2018 and 2017. General and administrative expenses exclude stock-based compensation expense of $39 million and $36 million for the six months ended June 30, 2018 and 2017, respectively. (c) See condensed consolidated statement of operations for further information.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Six Months Ended June 30, 2018 2017 Supplemental disclosure of cash flow information: Interest paid $ 292 $ 260 Income taxes paid 12 10 Supplemental disclosure of non-cash investing and financing activities: Increase (decrease) in accounts payable for purchases of property and equipment 22 (8 ) Purchase of property and equipment under capital leases and installment purchases 17 18 Preferred stock dividends declared but not paid (see note 10) 28 — The reconciliation of cash, cash equivalents, and restricted cash reported within various lines on the condensed consolidated balance sheet to amounts reported in the condensed consolidated statement of cash flows is shown below. June 30, 2018 December 31, 2017 Cash and cash equivalents $ 206 $ 314 Restricted cash, current 125 121 Restricted cash reported within long-term prepaid rent and other assets, net 5 5 Cash, cash equivalents and restricted cash $ 336 $ 440

Subsequent Events Subsequent Ev

Subsequent Events Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Events July 2018 Tower Revenue Notes In July 2018, certain of the Company's indirect subsidiaries 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 having 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") and have an expected life of five years with a final maturity of July 2043 and (2) $750 million aggregate principal amount of 4.241% senior secured tower revenue notes ("4.241% Notes") and have an expected life of 10 years with a final maturity of July 2048 . The Company used the 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. The Company expects to record a loss on retirement of long-term obligations during the third quarter of 2018 of approximately $33 million in connection with this repayment. In addition to the July 2018 Tower Revenue Notes described above, in connection with Exchange Act risk retention requirements, 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" in an amount equal to at least 5% of the fair value of the July 2018 Tower Revenue Notes. Common Stock Dividend On August 2, 2018 , the Company's board of directors declared a quarterly cash dividend of $1.05 per common share. The quarterly dividend will be paid on September 28, 2018 to common stockholders of record as of September 14, 2018 .

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Summary of Significant Accounting Policies [Abstract]
Recent accounting prounouncements	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 customers, the Company’s pattern of revenue recognition is 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 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 condensed consolidated statement of cash flows and certain disclosures. See note 12 . 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 condensed 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 is effective for the Company as of January 1, 2019. This guidance is required to be applied, at the Company's election, either using a (1) modified retrospective approach for all leases existing at, or entered into after, the beginning of the earliest comparative period presented, or (2) cumulative-effect approach for all leases existing at, or entered into, after the effective date. The Company expects to apply the guidance using the cumulative-effect approach, thereby applying the new guidance at the effective date, without adjusting the comparative periods and, if necessary, recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Although early adoption is permitted, the Company will not adopt the new guidance prior to January 1, 2019. With regard to the application of this guidance to the Towers segment, the Company expects that (1) its Towers lessee arrangements will continue to be classified as operating leases under the new guidance; (2) this guidance will have a material impact on its condensed consolidated balance sheet due to the addition of right-of-use assets and lease liabilities for lessee arrangements (which primarily consist of ground leases under the Company's towers); and (3) there will not be a material impact to its condensed consolidated statement of operations and condensed consolidated statement of cash flows. The Company is in the process of updating certain of its existing information technology systems to integrate the new guidance requirement with respect to its Tower segment. With regard to the application of this guidance to the Fiber segment, the Company (1) has established and is progressing through the various steps of a cross-functional project plan to assess the impact of the standard; (2) expects this guidance to have a material impact on its condensed consolidated balance sheet due to the addition of right-of-use assets and lease liabilities for lessee arrangements (which primarily consist of fiber-related leases); and (3) continues to assess additional impacts to its condensed consolidated financial statements, including the condensed consolidated statement of operations and the condensed consolidated statement of cash flows.

Acquisitions Purchase Price All

Acquisitions Purchase Price Allocation (Tables)	6 Months Ended
	Jun. 30, 2018
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The preliminary purchase price allocation for the Lightower Acquisition is shown below and is based upon a preliminary valuation which is subject to change as the Company obtains additional information with respect to fixed assets, intangible assets and certain liabilities. Preliminary Purchase Price Allocation Current assets $ 99 Property and equipment 2,194 Goodwill (a) 3,168 Other intangible assets, net (b) 2,177 Other non-current assets 30 Current liabilities (174 ) Other non-current liabilities (342 ) Net assets acquired (c) $ 7,152 (a) The preliminary 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) Predominately comprised of site rental contracts and customer 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.

Revenues (Tables)

Revenues (Tables)	6 Months Ended
	Jun. 30, 2018
Schedule of Contractual Revenues [Line Items]
Schedule of Contractual Revenue	The following table is a summary of the contracted amounts owed to the Company by customers pursuant to site rental contracts in effect as of June 30, 2018 . Six months ending December 31, Years ending December 31, 2018 2019 2020 2021 2022 Thereafter Total Contracted amounts (a) $ 2,039 $ 3,829 $ 3,552 $ 3,279 $ 3,054 $ 6,928 $ 22,681 (a) Excludes amounts related to network services, as those contracts generally have a duration of one year or less.

Debt and Other Obligations (Tab

Debt and Other Obligations (Tables)	6 Months Ended
	Jun. 30, 2018
Extinguishment of Debt [Line Items]
Schedule of Long-Term Debt Instruments	Original Issue Date Contractual Maturity Date (a) Balance as of June 30, 2018 Balance as of December 31, 2017 Stated Interest Rate as of June 30, 2018 (a) Bank debt - variable rate: 2016 Revolver Jan. 2016 Jun. 2023 (e) $ 315 (b)(d)(e) $ 980 3.4 % (e) 2016 Term Loan A Jan. 2016 Jun. 2023 (e) 2,383 2,397 3.3 % (e) Total bank debt 2,698 3,377 Securitized debt - fixed rate: Secured Notes, Series 2009-1, Class A-1 July 2009 Aug. 2019 22 32 6.3 % Secured Notes, Series 2009-1, Class A-2 July 2009 Aug. 2029 70 70 9.0 % Tower Revenue Notes, Series 2010-3 Jan. 2010 Jan. 2040 (c) — (d) 1,246 N/A Tower Revenue Notes, Series 2010-6 Aug. 2010 Aug. 2040 (c) (f) 996 995 4.9 % Tower Revenue Notes, Series 2015-1 May 2015 May 2042 (c) 298 297 3.2 % Tower Revenue Notes, Series 2015-2 May 2015 May 2045 (c) 693 692 3.7 % Total securitized debt 2,079 3,332 Bonds - fixed rate: 5.250% Senior Notes Oct. 2012 Jan. 2023 1,640 1,639 5.3 % 3.849% Secured Notes Dec. 2012 Apr. 2023 993 993 3.9 % 4.875% Senior Notes Apr. 2014 Apr. 2022 843 842 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 743 743 3.7 % 2.250% Senior Notes Sept. 2016 Sept. 2021 696 695 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 742 742 3.2 % 3.650% Senior Notes Aug. 2017 Sept. 2027 991 991 3.7 % 3.150% Senior Notes Jan. 2018 Jul. 2023 742 (d) — 3.2 % 3.800% Senior Notes Jan. 2018 Feb. 2028 988 (d) — 3.8 % Total bonds 10,957 9,223 Other: Capital leases and other obligations Various Various 222 227 Various Total debt and other obligations 15,956 16,159 Less: current maturities and short-term debt and other current obligations 112 115 Non-current portion of long-term debt and other long-term obligations $ 15,844 $ 16,044 (a) See the 2017 Form 10-K, including note 8, for additional information regarding the maturity and principal amortization provisions and interest rates relating to the Company's indebtedness. (b) As of June 30, 2018 , the undrawn availability under the 2016 Revolver was $ 3.9 billion . (c) If the respective series of such debt is not paid in full on or prior to an applicable 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 additional interest (of an additional approximately 5% per annum) will accrue on the respective series. See the 2017 Form 10-K for additional information regarding these provisions. (d) In January 2018 , the Company issued $750 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 ("3.15% Senior Notes") and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028 ("3.80% Senior Notes") (collectively, "January 2018 Senior Notes Offering"). 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. (e) In June 2018 , the Company entered into an amendment to the Credit Facility to (1) increase commitments on the 2016 Revolver by $750 million ,for total 2016 Revolver commitments of $4.25 billion , and (2) extend the maturity of the Credit Facility from August 2022 to June 2023 . Additionally, pursuant to this amendment and with regards to the Credit Facility, the Company is obligated to pay (1) interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.00% to 1.75%, and (2) commitment fees ranging from 0.125% and 0.35%, each of which is based on the Company's senior unsecured debt rating. (f) See note 13 for more information regarding the Company's July 2018 Tower Revenue Notes (as defined in note 13).
Schedule of Maturities of Long-term Debt	The following are the scheduled contractual maturities of the total debt and other long-term obligations of the Company outstanding as of June 30, 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. Six Months Ending December 31, Years Ending December 31, Unamortized Adjustments, Net Total Debt and Other Obligations Outstanding 2018 2019 2020 2021 2022 Thereafter Total Cash Obligations Scheduled contractual maturities $ 56 $ 105 $ 137 $ 1,699 $ 1,085 $ 12,984 $ 16,066 $ (110 ) $ 15,956
Schedule of Extinguishment of Debt [Table Text Block]	The following is a summary of purchases and redemptions of long-term debt during the six months ended June 30, 2018 . Principal Amount Cash Paid (a) Gains (Losses) January 2010 Tower Revenue Notes $ 1,250 $ 1,318 $ (71 ) (b) 2016 Term Loan A $ — $ — $ (3 ) (b) Total $ 1,250 $ 1,318 $ (74 ) (a) Exclusive of accrued interest. (b) Inclusive of the write off of respective deferred financing costs.
Components of Interest Expense and Amortization of Deferred Financing Costs	The components of interest expense and amortization of deferred financing costs are as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Interest expense on debt obligations $ 157 $ 139 $ 314 $ 271 Amortization of deferred financing costs and adjustments on long-term debt 5 5 11 9 Other, net of capitalized interest (4 ) (2 ) (7 ) (4 ) Total $ 158 $ 142 $ 318 $ 276

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures
Estimated Fair Values and Carrying Amounts of Assets and Liabilities	Level in Fair Value Hierarchy June 30, 2018 December 31, 2017 Carrying Amount Fair Value Carrying Amount Fair Value Assets: Cash and cash equivalents 1 $ 206 $ 206 $ 314 $ 314 Restricted cash, current and non-current 1 130 130 126 126 Liabilities: Total debt and other obligations 2 15,956 15,911 16,159 16,644

Per Share Information (Tables)

Per Share Information (Tables)	6 Months Ended
	Jun. 30, 2017
Per Share Information
Reconciliation of the Numerators and Denominators of the Basic and Diluted Per Share Computations	Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Net income (loss) attributable to CCIC stockholders $ 180 $ 112 $ 294 $ 231 Dividends on preferred stock (28 ) — (57 ) — Net income (loss) attributable to CCIC common stockholders for basic and diluted computations $ 152 $ 112 $ 237 $ 231 Weighted-average number of common shares outstanding (in millions): Basic weighted-average number of common stock outstanding 415 364 412 363 Effect of assumed dilution from potential issuance of common shares relating to restricted stock units 1 2 1 1 Diluted weighted-average number of common shares outstanding 416 366 413 364 Net income (loss) attributable to CCIC common stockholders, per common share: Basic $ 0.37 $ 0.31 $ 0.58 $ 0.64 Diluted $ 0.36 $ 0.31 $ 0.57 $ 0.64

Equity (Tables)

Equity (Tables)	6 Months Ended
	Jun. 30, 2018
Dividends Payable [Line Items]
Dividends Declared [Table Text Block]	During the six months ended June 30, 2018 , the following dividends were declared or paid: Equity Type Declaration Date Record Date Payment Date Dividends Per Share Aggregate Payment Amount 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) 6.875% Mandatory Convertible Preferred Stock December 15, 2017 January 15, 2018 February 1, 2018 $ 17.1875 $ 28 6.875% Mandatory Convertible Preferred Stock March 19, 2018 April 15, 2018 May 1, 2018 $ 17.1875 $ 28 6.875% Mandatory Convertible Preferred Stock June 22, 2018 July 15, 2018 August 1, 2018 $ 17.1875 $ 28 (a) Inclusive of dividends accrued for holders of unvested restricted stock units, which will be paid when and if the restricted stock units vest.

Operating Segments Operating Se

Operating Segments Operating Segments (Tables)	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Three Months Ended June 30, 2018 Three Months Ended June 30, 2017 Towers Fiber Other Consolidated Total Towers Fiber Other Consolidated Total Segment site rental revenues $ 771 $ 398 $ 1,169 $ 718 $ 151 $ 869 Segment network services and other revenues 158 3 161 158 11 169 Segment revenues 929 401 1,330 876 162 1,038 Segment site rental cost of operations 216 130 346 211 52 263 Segment network services and other cost of operations 94 3 97 96 8 104 Segment cost of operations (a)(b) 310 133 443 307 60 367 Segment site rental gross margin 555 268 823 507 99 606 Segment network services and other gross margin 64 — 64 62 3 65 Segment general and administrative expenses (b) 27 44 71 23 19 42 Segment operating profit (loss) 592 224 816 546 83 629 Other general and administrative expenses (b) $ 47 47 $ 41 41 Stock-based compensation expense 26 26 17 17 Depreciation, amortization and accretion 379 379 296 296 Interest expense and amortization of deferred financing costs 158 158 142 142 Other income (expenses) to reconcile to income (loss) before income taxes (c) 21 21 16 16 Income (loss) before income taxes $ 185 $ 117 Capital expenditures $ 98 $ 289 $ 6 $ 393 $ 107 $ 188 $ 6 $ 301 Total assets (at period end) $ 17,780 $ 14,100 $ 494 $ 32,374 $ 18,208 $ 5,811 $ 465 $ 24,484 (a) Exclusive of depreciation, amortization and accretion shown separately. (b) Segment cost of operations excludes (1) stock-based compensation expense of $6 million and $2 million for the three months ended June 30, 2018 and 2017 , respectively, and (2) prepaid lease purchase price adjustments of $5 million for both of the three months ended June 30, 2018 and 2017 . General and administrative expenses exclude stock-based compensation expense of $20 million and $15 million for the three months ended June 30, 2018 and 2017 , respectively. (c) See condensed consolidated statement of operations for further information.	Six Months Ended June 30, 2018 Six Months Ended June 30, 2017 Towers Fiber Other Consolidated Total Towers Fiber Other Consolidated Total Segment site rental revenues $ 1,536 $ 787 $ 2,323 $ 1,434 $ 292 $ 1,726 Segment network services and other revenues 300 7 307 308 20 328 Segment revenues 1,836 794 2,630 1,742 312 2,054 Segment site rental cost of operations 427 256 683 420 99 519 Segment network services and other cost of operations 176 5 181 185 17 202 Segment cost of operations (a)(b) 603 261 864 605 116 721 Segment site rental gross margin 1,109 531 1,640 1,014 193 1,207 Segment network services and other gross margin 124 2 126 123 3 126 Segment general and administrative expenses (b) 53 87 140 47 36 83 Segment operating profit (loss) 1,180 446 1,626 1,090 160 1,250 Other general and administrative expenses (b) $ 94 94 $ 80 80 Stock-based compensation expense 52 52 42 42 Depreciation, amortization and accretion 753 753 584 584 Interest expense and amortization of deferred financing costs 318 318 276 276 Other income (expenses) to reconcile to income (loss) before income taxes (c) 106 106 28 28 Income (loss) before income taxes $ 303 $ 240 Capital expenditures $ 195 $ 552 $ 16 $ 763 $ 208 $ 342 $ 13 $ 563 (a) Exclusive of depreciation, amortization and accretion shown separately. (b) Segment cost of operations excludes (1) stock-based compensation expense of $13 million and $ 6 million for the six months ended June 30, 2018 and 2017, respectively, and (2) prepaid lease purchase price adjustments of $10 million for both of the six months ended June 30, 2018 and 2017. General and administrative expenses exclude stock-based compensation expense of $39 million and $36 million for the six months ended June 30, 2018 and 2017, respectively. (c) See condensed consolidated statement of operations for further information.

Supplemental Cash Flow Inform28

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2018
Schedule of Cash, Cash Equivalents and Restricted Cash [Line Items]
Schedule of Cash, Cash Equivalents and Restricted Cash [Table Text Block]	The reconciliation of cash, cash equivalents, and restricted cash reported within various lines on the condensed consolidated balance sheet to amounts reported in the condensed consolidated statement of cash flows is shown below. June 30, 2018 December 31, 2017 Cash and cash equivalents $ 206 $ 314 Restricted cash, current 125 121 Restricted cash reported within long-term prepaid rent and other assets, net 5 5 Cash, cash equivalents and restricted cash $ 336 $ 440
Supplemental Disclosure of Cash Flow Information and Non-cash Investing and Financing Activities	Six Months Ended June 30, 2018 2017 Supplemental disclosure of cash flow information: Interest paid $ 292 $ 260 Income taxes paid 12 10 Supplemental disclosure of non-cash investing and financing activities: Increase (decrease) in accounts payable for purchases of property and equipment 22 (8 ) Purchase of property and equipment under capital leases and installment purchases 17 18 Preferred stock dividends declared but not paid (see note 10) 28 —

General Business (Details)

General Business (Details)	Jun. 30, 2018
Subject to Capital Lease with Sprint, TMO, or AT&T [Member]
Purchase Option, Percentage of Towers	53.00%

Acquisitions (Details)

Acquisitions (Details) - Lightower Acquisition [Member] $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	$ 7,100
Fiber Miles Acquired	32,000
Business Acquisition, Date of Acquisition Agreement	Nov. 1, 2017
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	3,168	[1]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets	2,177	[2]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	30
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities	(174)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities	(342)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 7,152	[3]
[1]	The preliminary 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.
[2]	Predominately comprised of site rental contracts and customer relationships.
[3]	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.

Revenues (Details)

Revenues (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2018	Dec. 31, 2017
Revenue, Performance Obligation, Description of Payment Terms		45
Revenue, Remaining Performance Obligation		$ 2,200	$ 2,100
Revenue Recognized on Deferred Revenues		200
Contracted Amounts Receivable from Customers, Current	[1]	2,039
Contracted Amounts Receivable from Customers, in Two Years	[1]	3,829
Contracted Amounts Receivable from Customers, in Three Years	[1]	3,552
Contracted Amounts Receivable from Customers, in Four Years	[1]	3,279
Contracted Amounts Receivable from Customers, in Five Years	[1]	3,054
Contracted Amounts Receivable from Customers, Thereafter	[1]	6,928
Contracted Amounts Receivable from Customers, Total	[1]	22,681
Non-current
Assets Related to Straight Line Site Rental Revenues		1,300
Current
Assets Related to Straight Line Site Rental Revenues		$ 121
[1]	Excludes amounts related to network services, as those contracts generally have a duration of one year or less.

Debt and Other Obligations (Ind

Debt and Other Obligations (Indebtedness) (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Mar. 31, 2018	Jun. 30, 2018		Dec. 31, 2017
Debt Instrument [Line Items]
Credit Facility Amendment, Date			Jun. 1, 2018
Debt and Capital Lease Obligations			$ 15,956		$ 16,159
Less: current maturities and short-term debt and other current obligations			112		115
Non-current portion of long-term debt and other long-term obligations			$ 15,844		16,044
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		3.20%
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%
Variable Rate Revolver 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date			Jun. 1, 2023
Line of Credit Facility, Change in Borrowing Capacity			$ 750
Line of Credit Facility, Maximum Borrowing Capacity			4,250
Debt Instrument, Unused Borrowing Capacity, Amount			$ 3,900
Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Contractual maturity date	[1]		Various
Original Debt Issuance Date			Various
Percentage of debt instrument interest rate stated	[1]		Various
Debt and Capital Lease Obligations			$ 222		227
Fixed Rate Securitized Debt 2010 Tower Revenue Notes [Member]
Debt Instrument [Line Items]
Debt Instrument Additional Interest Rate if not Repaid Prior to Applicable Date			5.00%
January 2018 Senior Note [Member]
Debt Instrument [Line Items]
Original issue date			Jan. 1, 2018
Bank Debt [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations			$ 2,698		3,377
Bank Debt [Member] | Variable Rate Revolver 2016 [Member]
Debt Instrument [Line Items]
Original issue date			Jan. 1, 2016
Debt Instrument, Maturity Date	[2],[3]		Jun. 1, 2023
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.40%
Debt and Capital Lease Obligations			$ 315	[3],[4],[5]	980
Bank Debt [Member] | Variable Rate 2016 Term Loan A [Member]
Debt Instrument [Line Items]
Original issue date			Jan. 1, 2016
Debt Instrument, Maturity Date	[2],[3]		Jun. 1, 2023
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.30%
Debt and Capital Lease Obligations			$ 2,383		2,397
Securitized Debt [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations			$ 2,079		3,332
Securitized Debt [Member] | Fixed Rate Debt 2009 Securitized Notes First Tranche [Member]
Debt Instrument [Line Items]
Original issue date			Jul. 1, 2009
Debt Instrument, Maturity Date	[1]		Aug. 1, 2019
Debt Instrument, Interest Rate, Stated Percentage	[1]		6.30%
Debt and Capital Lease Obligations			$ 22		32
Securitized Debt [Member] | Fixed Rate Securitized Debt January 2010 Tower Revenue Notes Third Tranche [Member]
Debt Instrument [Line Items]
Original issue date			Jan. 1, 2010
Debt Instrument, Maturity Date	[1],[6]		Jan. 1, 2040
Debt and Capital Lease Obligations			$ 0	[5]	1,246
Securitized Debt [Member] | Fixed Rate Securitized Debt August 2010 Tower Revenue Notes Third Tranche [Member]
Debt Instrument [Line Items]
Original issue date			Aug. 1, 2010
Debt Instrument, Maturity Date	[1],[6],[7]		Aug. 1, 2040
Debt Instrument, Interest Rate, Stated Percentage	[1]		4.88%
Debt and Capital Lease Obligations			$ 996		995
Securitized Debt [Member] | Fixed Rate Debt 2009 Securitized Notes Second Tranche [Member]
Debt Instrument [Line Items]
Original issue date			Jul. 1, 2009
Debt Instrument, Maturity Date	[1]		Aug. 1, 2029
Debt Instrument, Interest Rate, Stated Percentage	[1]		9.00%
Debt and Capital Lease Obligations			$ 70		70
Securitized Debt [Member] | 2015 Tower Revenue Notes 3.222% due 2042 [Member]
Debt Instrument [Line Items]
Original issue date			May 1, 2015
Debt Instrument, Maturity Date	[1],[6]		May 1, 2042
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.22%
Debt and Capital Lease Obligations			$ 298		297
Securitized Debt [Member] | 2015 Tower Revenue Notes 3.663% due 2045 [Member]
Debt Instrument [Line Items]
Original issue date			May 1, 2015
Debt Instrument, Maturity Date	[1],[6]		May 1, 2045
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.66%
Debt and Capital Lease Obligations			$ 693		692
High Yield Bonds [Member]
Debt Instrument [Line Items]
Debt and Capital Lease Obligations			$ 10,957		9,223
High Yield Bonds [Member] | September 2016 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Original issue date			Sep. 1, 2016
Debt Instrument, Maturity Date	[1]		Sep. 1, 2021
Debt Instrument, Interest Rate, Stated Percentage	[1]		2.30%
Debt and Capital Lease Obligations			$ 696		695
High Yield Bonds [Member] | February 2017 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Original issue date			Feb. 1, 2017
Debt Instrument, Maturity Date	[1]		Mar. 1, 2027
Debt Instrument, Interest Rate, Stated Percentage	[1]		4.00%
Debt and Capital Lease Obligations			$ 494		494
High Yield Bonds [Member] | May 2017 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Original issue date			May 1, 2017
Debt Instrument, Maturity Date	[1]		May 1, 2047
Debt Instrument, Interest Rate, Stated Percentage	[1]		4.80%
Debt and Capital Lease Obligations			$ 343		343
High Yield Bonds [Member] | August 2017 Senior Unsecured 3.200% Notes [Member]
Debt Instrument [Line Items]
Original issue date			Aug. 1, 2017
Debt Instrument, Maturity Date	[1]		Sep. 1, 2024
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.20%
Debt and Capital Lease Obligations			$ 742		742
High Yield Bonds [Member] | August 2017 Senior Unsecured 3.650% Notes [Member]
Debt Instrument [Line Items]
Original issue date			Aug. 1, 2017
Debt Instrument, Maturity Date	[1]		Sep. 1, 2027
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.70%
Debt and Capital Lease Obligations			$ 991		991
High Yield Bonds [Member] | 3.150% Senior Notes [Member]
Debt Instrument [Line Items]
Original issue date			Jan. 1, 2018
Debt Instrument, Maturity Date	[1]		Jul. 1, 2023
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.20%
Debt and Capital Lease Obligations			$ 742	[5]	0
High Yield Bonds [Member] | 3.800% Senior Notes [Member]
Debt Instrument [Line Items]
Original issue date			Jan. 1, 2018
Debt Instrument, Maturity Date	[1]		Feb. 1, 2028
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.80%
Debt and Capital Lease Obligations			$ 988	[5]	0
High Yield Bonds [Member] | Five and One Fourth Senior Notes [Member]
Debt Instrument [Line Items]
Original issue date			Oct. 1, 2012
Debt Instrument, Maturity Date	[1]		Jan. 15, 2023
Debt Instrument, Interest Rate, Stated Percentage	[1]		5.30%
Debt and Capital Lease Obligations			$ 1,640		1,639
High Yield Bonds [Member] | 2012 secured notes tranche B [Member]
Debt Instrument [Line Items]
Original issue date			Dec. 1, 2012
Debt Instrument, Maturity Date	[1]		Apr. 15, 2023
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.90%
Debt and Capital Lease Obligations			$ 993		993
High Yield Bonds [Member] | 4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Original issue date			Apr. 1, 2014
Debt Instrument, Maturity Date	[1]		Apr. 1, 2022
Debt Instrument, Interest Rate, Stated Percentage	[1]		4.90%
Debt and Capital Lease Obligations			$ 843		842
High Yield Bonds [Member] | Senior Unsecured 2016 Notes 3.40% [Member]
Debt Instrument [Line Items]
Original issue date			Feb. 1, 2016
Debt Instrument, Maturity Date	[1]		Feb. 15, 2021
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.40%
Debt and Capital Lease Obligations			$ 850		850
High Yield Bonds [Member] | Senior Unsecured 2016 Notes 3.7% [Member]
Debt Instrument [Line Items]
Original issue date			May 1, 2016
Debt Instrument, Maturity Date	[1]		Jun. 15, 2026
Debt Instrument, Interest Rate, Stated Percentage	[1]		3.70%
Debt and Capital Lease Obligations			$ 743		743
High Yield Bonds [Member] | Senior Unsecured 2016 Notes 4.450% [Member]
Debt Instrument [Line Items]
Original issue date			Feb. 1, 2016
Debt Instrument, Maturity Date	[1]		Feb. 15, 2026
Debt Instrument, Interest Rate, Stated Percentage	[1]		4.50%
Debt and Capital Lease Obligations			$ 892		$ 891
[1]	See the 2017 Form 10-K, including note 8, for additional information regarding the maturity and principal amortization provisions and interest rates relating to the Company's indebtedness.
[2]	Exclusive of accrued interest
[3]	In June 2018, the Company entered into an amendment to the Credit Facility to (1) increase commitments on the 2016 Revolver by $750 million,for total 2016 Revolver commitments of $4.25 billion, and (2) extend the maturity of the Credit Facility from August 2022 to June 2023.
[4]	As of June 30, 2018, the undrawn availability under the 2016 Revolver was $3.9 billion.
[5]	In January 2018, the Company issued $750 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 ("3.15% Senior Notes") and $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028 ("3.80% Senior Notes") (collectively, "January 2018 Senior Notes Offering"). 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.
[6]	If the respective series of such debt is not paid in full on or prior to an applicable 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 additional interest (of an additional approximately 5% per annum) will accrue on the respective series. See the 2017 Form 10-K for additional information regarding these provisions.
[7]	See note 13 for more information regarding the Company's July 2018 Tower Revenue Notes (as defined in note 13).

Debt and Other Obligations (Com

Debt and Other Obligations (Components of Interest Expense and Amortization of Deferred Financing Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Debt and Other Obligations [Abstract]
Interest expense on debt obligations	$ 157	$ 139	$ 314	$ 271
Amortization of deferred financing costs and adjustments on long-term debt	5	5	11	9
Other	(4)	(2)	(7)	(4)
Total	$ 158	$ 142	$ 318	$ 276

Debt and Other Obligations Cont

Debt and Other Obligations Contractual Maturities (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Contractual Maturities [Abstract]
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year	$ 56
Long-term Debt, Maturities, Repayments of Principal in Year Two	105
Long-term Debt, Maturities, Repayments of Principal in Year Three	137
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,699
Long-term Debt, Maturities, Repayments of Principal in Year Five	1,085
Long-term Debt, Maturities, Repayments of Principal after Year Five	12,984
Unamortized Adjustments, Net	(110)
Debt and Capital Lease Obligations	15,956	$ 16,159
Total Cash Obligations	$ 16,066

Debt and Other Obligations Sche

Debt and Other Obligations Schedule of Extinguishment of Long Term Debt (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Extinguishment of Debt [Line Items]
Gain (Loss) on Extinguishment of Debt		$ (3)	$ 0	$ (74)	$ (4)
January 2010 Tower Revenue Notes [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount				1,250
Repayments of Debt	[1]			1,318
Gain (Loss) on Extinguishment of Debt	[2]			(71)
2016 Term Loan A [Member]
Extinguishment of Debt [Line Items]
Extinguishment of Debt, Amount				0
Repayments of Debt				0
Gain (Loss) on Extinguishment of Debt	[3]			$ (3)
[1]	Exclusive of accrued interest
[2]	Inclusive of the write off of respective deferred financing costs.
[3]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjMwYmFhYmQzNDhkYzQ5ZjlhODZmNmE5MzJmNTUyNmYyfFRleHRTZWxlY3Rpb246ODBBNUUwNDQzQUVGOTIyRUMyMTZDRDM2Rjc1MTAyNTkM}

Fair Value Disclosures (Estimat

Fair Value Disclosures (Estimated Fair Values and Carrying Amounts of Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, at carrying value	$ 206	$ 314
Cash and cash equivalents, fair value	206	314
Restricted cash, current and non-current, carrying value	130	126
Restricted cash, current and non-current, fair value	130	126
Long-term debt and other obligations, carrying amount	15,956	16,159
Long-term debt and other obligations, fair value	$ 15,911	$ 16,644

Per Share Information (Reconcil

Per Share Information (Reconciliation of the Numerators and Denominators of the Basic and Diluted Per Share Computations) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Per Share Information
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 180	$ 112	$ 294	$ 231
Dividends on preferred stock	28	0	57	0
Net income (loss) attributable to CCIC common stockholders for basic and diluted computations	$ 152	$ 112	$ 237	$ 231
Basic weighted-average number of common stock outstanding	415	364	412	363
Effect of assumed dilution from potential common shares relating to restricted stock units	1	2	1	1
Diluted weighted-average number of common shares outstanding	416	366	413	364
Basic	$ 0.37	$ 0.31	$ 0.58	$ 0.64
Diluted	$ 0.36	$ 0.31	$ 0.57	$ 0.64

Per Share Information (Narrativ

Per Share Information (Narrative) (Details) shares in Millions	6 Months Ended
	Jun. 30, 2018shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock Issued During Period, Shares, Restricted Stock Award, Gross	1
Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from dilutive common shares calculation	16

Commitments and Contingencies C

Commitments and Contingencies Commitment and Contingencies (Details)	Jun. 30, 2018
Subject to Capital Lease with Sprint, TMO, or AT&T [Member]
Other Commitments [Line Items]
Purchase Option, Percentage of Towers	53.00%

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended			6 Months Ended
		Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017
Dividends Payable [Line Items]
Common Stock, Dividends, Per Share, Cash Paid	[1]		$ 1.050	$ 1.050
Preferred Stock, Dividends Per Share, Declared		$ 17.1875	$ 17.1875	$ 17.1875
Dividends, Common Stock, Cash	[1]		$ 438	$ 439
Dividends, Preferred Stock, Cash		$ 28	$ 28	$ 28
Common stock repurchased during period, shares					0.3
Purchases of capital stock					$ 34	$ 23
Common Stock [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared	[1]		May 17, 2018	Feb. 21, 2018
Dividends Payable, Date of Record	[1]		Jun. 15, 2018	Mar. 16, 2018
Dividends Payable, Date to be Paid	[1]		Jun. 29, 2018	Mar. 30, 2018
Preferred Stock [Member]
Dividends Payable [Line Items]
Dividends Payable, Date Declared		Jun. 22, 2018	Mar. 19, 2018	Dec. 15, 2017
Dividends Payable, Date of Record		Jul. 15, 2018	Apr. 15, 2018	Jan. 15, 2018
Dividends Payable, Date to be Paid		Aug. 1, 2018	May 1, 2018	Feb. 1, 2018
[1]	Inclusive of dividends accrued for holders of unvested restricted stock units, which will be paid when and if the restricted stock units vest.

Equity Other Equity Activity (D

Equity Other Equity Activity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock				$ 841	$ 464
2015 ATM Program, Life to Date Proceeds, Gross	$ 350			350
2015 ATM Program, capacity remaining	150			150
Availability Under ATM	$ 750			$ 750
Preferred Stock, Par or Stated Value Per Share	$ 0.01			$ 0.01		$ 0.01
2015 ATM, Aggregate Value of Common Stock	$ 500			$ 500
March 2018 Equity Financing [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock		$ 841
Stock Issued During Period, Shares, New Issues		8
Common Stock [Member]
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock	$ 0
Stock Issued During Period, Shares, New Issues	0		5	8	4

Equity Schedule of Equity by Ty

Equity Schedule of Equity by Type (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock			$ 841	$ 464
Common Stock [Member]
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	0	5	8	4
Proceeds from Issuance of Common Stock	$ 0

Operating Segments Operating 43

Operating Segments Operating Segments Table (Details) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2018USD ($)		Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)		Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Tower Count		40,000			40,000
Segment site rental revenues		$ 1,169		$ 869	$ 2,323		$ 1,726
Segment network services and other revenues		$ 161		169	$ 307		328
Fiber Miles		60,000			60,000
Segment revenues		$ 1,330		1,038	$ 2,630		2,054
Segment site rental cost of operations	[1]	355		269	702		534
Segment network services and other cost of operations	[1]	99		104	185		203
Segment general and administrative expenses		138		98	273		199
Stock-based compensation expense					47		45
Depreciation, Amortization and Accretion, Net		379		296	753		584
Interest expense and amortization of deferred financing costs		158		142	318		276
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		185		117	303		240
Capital expenditures					763		563
Total Assets		32,374			32,374			$ 32,229
Amortization of prepaid lease purchase price adjustments		5			10
Segment cost of operations share-based compensation [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense		6		2	13		6
Towers [Member]
Segment Reporting Information [Line Items]
Segment site rental revenues		771		718	1,536		1,434
Segment network services and other revenues		158		158	300		308
Segment revenues		929		876	1,836		1,742
Segment site rental cost of operations		216		211	427		420
Segment network services and other cost of operations		94		96	176		185
Segment cost of operations	[2]	310		307	603		605
Segment site rental gross margin		555		507	1,109		1,014
Segment network services gross margin		64		62	124		123
Segment general and administrative expenses	[2]	27		23	53		47
Segment Operating Profit		592		546	1,180		1,090
Capital expenditures		98		107	195		208
Total Assets		17,780		18,208	17,780		18,208
Small Cells [Member]
Segment Reporting Information [Line Items]
Segment site rental revenues		398		151	787		292
Segment network services and other revenues		3		11	7		20
Segment revenues		401		162	794		312
Segment site rental cost of operations		130		52	256		99
Segment network services and other cost of operations		3		8	5		17
Segment cost of operations	[2]	133		60	261		116
Segment site rental gross margin		268		99	531		193
Segment network services gross margin		0		3	2		3
Segment general and administrative expenses	[2]	44		19	87		36
Segment Operating Profit		224		83	446		160
Capital expenditures		289		188	552		342
Total Assets		14,100		5,811	14,100		5,811
Consolidated Total [Member]
Segment Reporting Information [Line Items]
Segment site rental revenues		1,169		869	2,323		1,726
Segment network services and other revenues		161		169	307		328
Segment revenues		1,330		1,038	2,630		2,054
Segment site rental cost of operations		346		263	683		519
Segment network services and other cost of operations		97		104	181		202
Segment cost of operations	[2]	443		367	864		721
Segment site rental gross margin		823		606	1,640		1,207
Segment network services gross margin		64		65	126		126
Segment general and administrative expenses	[2]	71		42	140		83
Segment Operating Profit		816		629	1,626		1,250
Stock-based compensation expense		26		17	52		42
Depreciation, Amortization and Accretion, Net		379		296	753		584
Interest expense and amortization of deferred financing costs		158		142	318		276
Other expenses to reconcile to income (loss) from continuing operations before income taxes		21		16	106		28
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest		185		117	303		240
Capital expenditures		393		301	763		563
Total Assets		32,374		24,484	32,374		24,484
Other [Member]
Segment Reporting Information [Line Items]
Segment general and administrative expenses		47	[2]		94	[2]	80
Segment Operating Profit
Stock-based compensation expense		26			52		42
Depreciation, Amortization and Accretion, Net		379			753		584
Interest expense and amortization of deferred financing costs		158			318		276
Other expenses to reconcile to income (loss) from continuing operations before income taxes		21			106		28
Capital expenditures		6		6	16		13
Total Assets		494		465	494		465
Segment G&A share-based compensation [Member]
Segment Reporting Information [Line Items]
Stock-based compensation expense		$ 20		$ 15	$ 39		$ 36
[1]	Exclusive of depreciation, amortization and accretion shown separately.
[2]	Segment cost of operations excludes (1) stock-based compensation expense of $6 million and $2 million for the three months ended June 30, 2018 and 2017, respectively, and (2) prepaid lease purchase price adjustments of $5 million for both of the three months ended June 30, 2018 and 2017. General and administrative expenses exclude stock-based compensation expense of $20 million and $15 million for the three months ended June 30, 2018 and 2017, respectively.

Supplemental Cash Flow Inform44

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Supplemental Cash Flow Information [Line Items]
Cash and cash equivalents	$ 206		$ 314
Interest paid	292	$ 260
Income taxes paid	12	10
Increase (decrease) in accounts payable for purchases of property and equipment	22	(8)
Purchase of property and equipment under capital leases and installment purchases	17	18
Restricted Cash, Current	125		121
Restricted Cash, Noncurrent	5		5
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	336		$ 440
Preferred Stock [Member]
Supplemental Cash Flow Information [Line Items]
Preferred Stock Dividends Declared, Not Paid	$ 28	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Cash Paid	[1]	$ 1.050	$ 1.050
2018 ATM, Aggregate Value of Common Stock		$ 500		$ 500
Common Stock [Member]
Subsequent Event [Line Items]
Dividends Payable, Date to be Paid	[1]	Jun. 29, 2018	Mar. 30, 2018
Dividends Payable, Date of Record	[1]	Jun. 15, 2018	Mar. 16, 2018
Dividends Payable, Date Declared	[1]	May 17, 2018	Feb. 21, 2018
Lightower Acquisition [Member]
Subsequent Event [Line Items]
Business Acquisition, Date of Acquisition Agreement				Nov. 1, 2017
Dividend Declared [Member] | Common Stock [Member]
Subsequent Event [Line Items]
Dividends Payable, Date to be Paid				Sep. 28, 2018
Dividends Payable, Date of Record				Sep. 14, 2018
Dividends Payable, Date Declared				Aug. 2, 2018
Paid subsequent to year end [Member]
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Cash Paid		$ 1.050
July 2018 Tower Revenue Notes [Member] | Issuance of debt obligation [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount		$ 1,000		$ 1,000
3.720% July 2018 Tower Revenue Notes [Member] | Issuance of debt obligation [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount			$ 250
Debt Instrument, Interest Rate, Stated Percentage			3.70%
Debt Instrument, Maturity Date			Jul. 1, 2043
4.241% July 2018 Tower Revenue Notes [Member] | Issuance of debt obligation [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount			$ 750
Debt Instrument, Interest Rate, Stated Percentage			4.20%
Debt Instrument, Maturity Date			Jul. 1, 2048
2018 Tower Revenue Notes Risk Retention Tranche [Member] | Issuance of debt obligation [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount			$ 53
[1]	Inclusive of dividends accrued for holders of unvested restricted stock units, which will be paid when and if the restricted stock units vest.