T-Mobile US (TMUS) 10-K 6 Feb 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 28, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-33409
Entity Registrant Name	T-MOBILE US, INC.
Entity Central Index Key	0001283699
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-0836269
Entity Address, Address Line One	12920 SE 38th Street
Entity Address, City or Town	Bellevue
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98006-1350
City Area Code	(425)
Local Phone Number	378-4000
Title of 12(b) Security	Common Stock, par value $0.00001 per share
Trading Symbol	TMUS
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 23.2
Entity Common Stock, Shares Outstanding		856,932,845
Documents Incorporated by Reference	Part III of this Annual Report on Form 10-K will be incorporated by reference from certain portions of the definitive Proxy Statement for the Registrant’s Annual Meeting of Stockholders, which definitive Proxy Statement will be filed with the Securities and Exchange Commission pursuant to Regulation 14A or will be included in an amendment to this Report.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 1,528	$ 1,203
Accounts receivable, net of allowances of $61 and $67	1,888	1,769
Equipment installment plan receivables, net	2,600	2,538
Accounts receivable from affiliates	20	11
Inventory	964	1,084
Other current assets	2,305	1,676
Total current assets	9,305	8,281
Property and equipment, net	21,984	23,359
Operating lease right-of-use assets	10,933
Financing lease right-of-use assets	2,715
Goodwill	1,930	1,901
Spectrum licenses	36,465	35,559
Other intangible assets, net	115	198
Equipment installment plan receivables due after one year, net	1,583	1,547
Other assets	1,891	1,623
Total assets	86,921	72,468
Current liabilities
Accounts payable and accrued liabilities	6,746	7,741
Payables to affiliates	187	200
Short-term debt	25
Short-term debt	25	841
Deferred revenue	631	698
Short-term operating lease liabilities	2,287
Short-term financing lease liabilities	957
Other current liabilities	1,673	787
Total current liabilities	12,506	10,267
Long-term debt	10,958	12,124
Long-term debt to affiliates	13,986	14,582
Tower obligations	2,236	2,557
Deferred tax liabilities	5,607	4,472
Operating lease liabilities	10,539
Financing lease liabilities	1,346
Deferred rent expense		2,781
Other long-term liabilities	954	967
Total long-term liabilities	45,626	37,483
Commitments and contingencies (Note 16)
Stockholders' equity
Common Stock, par value $0.00001 per share, 1,000,000,000 shares authorized; 858,418,615 and 851,675,119 shares issued, 856,905,400 and 850,180,317 shares outstanding	0	0
Additional paid-in capital	38,498	38,010
Treasury stock, at cost,1,513,215 and 1,494,802 shares issued	(8)	(6)
Accumulated other comprehensive loss	(868)	(332)
Accumulated deficit	(8,833)	(12,954)
Total stockholders' equity	28,789	24,718
Total liabilities and stockholders' equity	$ 86,921	$ 72,468

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowances	$ 61	$ 67
Common stock, par value (in USD per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	858,418,615	851,675,119
Common stock, shares outstanding (in shares)	856,905,400	850,180,317
Treasury stock, at cost (in shares)	1,513,215	1,494,802

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Revenues	$ 44,998	$ 43,310	$ 40,604
Operating expenses
Selling, general and administrative	14,139	13,161	12,259
Depreciation and amortization	6,616	6,486	5,984
Gains on disposal of spectrum licenses	0	0	(235)
Total operating expenses	39,276	38,001	35,716
Operating income	5,722	5,309	4,888
Other income (expense)
Interest expense	(727)	(835)	(1,111)
Interest expense to affiliates	(408)	(522)	(560)
Interest income	24	19	17
Other expense, net	(8)	(54)	(73)
Total other expense, net	(1,119)	(1,392)	(1,727)
Income before income taxes	4,603	3,917	3,161
Income tax expense	(1,135)	(1,029)	1,375
Net income	3,468	2,888	4,536
Preferred Stock Dividends and Other Adjustments	0	0	(55)
Net income attributable to common stockholders	3,468	2,888	4,481
Net income	3,468	2,888	4,536
Other comprehensive (loss) income, net of tax
Unrealized gain on available-for-sale securities, net of tax effect of $0, $0, and $2	0	0	7
Unrealized loss on cash flow hedges, net of tax effect of $(187), $(115), and $0	(536)	(332)	0
Other comprehensive income (loss)	(536)	(332)	7
Total comprehensive income	$ 2,932	$ 2,556	$ 4,543
Earnings per share
Basic (in USD per share)	$ 4.06	$ 3.40	$ 5.39
Diluted (in USD per share)	$ 4.02	$ 3.36	$ 5.20
Weighted average shares outstanding
Basic (in shares)	854,143,751	849,744,152	831,850,073
Diluted (in shares)	863,433,511	858,290,174	871,787,450
Branded postpaid revenues
Revenues
Revenues	$ 22,673	$ 20,862	$ 19,448
Branded prepaid revenues
Revenues
Revenues	9,543	9,598	9,380
Wholesale revenues
Revenues
Revenues	1,279	1,183	1,102
Roaming and other service revenues
Revenues
Revenues	499	349	230
Service
Revenues
Revenues	33,994	31,992	30,160
Operating expenses
Cost of services and equipment sales	6,622	6,307	6,100
Equipment
Revenues
Revenues	9,840	10,009	9,375
Operating expenses
Cost of services and equipment sales	11,899	12,047	11,608
Other revenues
Revenues
Revenues	$ 1,164	$ 1,309	$ 1,069

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Unrealized gain on available-for-sale securities	$ 0	$ 0	$ 2
Cash flow hedges, tax effect	$ (187)	$ (115)	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income		$ 3,468	$ 2,888	$ 4,536
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization		6,616	6,486	5,984
Stock-based compensation expense		495	424	306
Deferred income tax expense (benefit)		1,091	980	(1,404)
Bad debt expense		307	297	388
Losses from sales of receivables		130	157	299
Deferred rent expense		0	26	76
Losses on redemption of debt		19	122	86
Gains on disposal of spectrum licenses		0	0	(235)
Changes in operating assets and liabilities
Accounts receivable		(3,709)	(4,617)	(3,931)
Equipment installment plan receivables		(1,015)	(1,598)	(1,812)
Inventories		(617)	(201)	(844)
Operating lease right-of-use assets		1,896
Other current and long-term assets		(144)	(181)	(575)
Accounts payable and accrued liabilities		17	(867)	1,079
Short and long-term operating lease liabilities		(2,131)
Other current and long-term liabilities		144	(69)	(233)
Other, net		257	52	111
Net cash provided by operating activities		6,824	3,899	3,831
Investing activities
Purchases of property and equipment, including capitalized interest of $473, $362 and $136		(6,391)	(5,541)	(5,237)
Purchases of spectrum licenses and other intangible assets, including deposits		(967)	(127)	(5,828)
Proceeds from sales of tower sites		38	0	0
Proceeds related to beneficial interests in securitization transactions		3,876	5,406	4,319
Net cash related to derivative contracts under collateral exchange arrangements		(632)	0	0
Acquisition of companies, net of cash acquired		(31)	(338)	0
Other, net		(18)	21	1
Net cash used in investing activities		(4,125)	(579)	(6,745)
Financing activities
Proceeds from issuance of long-term debt		0	2,494	10,480
Proceeds from borrowing on revolving credit facility		2,340	6,265	2,910
Repayments of revolving credit facility		(2,340)	(6,265)	(2,910)
Repayments of financing lease obligations		(798)	(700)	(486)
Repayments of short-term debt for purchases of inventory, property and equipment, net		(775)	(300)	(300)
Repayments of long-term debt		(600)	(3,349)	(10,230)
Repurchases of common stock		0	(1,071)	(427)
Tax withholdings on share-based awards		(156)	(146)	(166)
Dividends on preferred stock		0	0	(55)
Cash payments for debt prepayment or debt extinguishment costs		(28)	(212)	(188)
Other, net		(17)	(52)	5
Net cash used in financing activities		(2,374)	(3,336)	(1,367)
Change in cash and cash equivalents		325	(16)	(4,281)
Cash and cash equivalents
Beginning of period		1,203	1,219	5,500
End of period		1,528	1,203	1,219
Supplemental disclosure of cash flow information
Interest payments, net of amounts capitalized		1,128	1,525	2,028
Operating lease payments	[1]	2,783
Income tax payments		88	51	31
Non-cash investing and financing activities
Non-cash beneficial interest obtained in exchange for securitized receivables		6,509	4,972	4,063
(Decrease) increase in accounts payable for purchases of property and equipment		(935)	65	313
Leased devices transferred from inventory to property and equipment		1,006	1,011	1,131
Returned leased devices transferred from property and equipment to inventory		(267)	(326)	(742)
Short-term debt assumed for financing of property and equipment		800	291	292
Operating lease right-of-use assets obtained in exchange for lease obligations		3,621
Financing lease right-of-use assets obtained in exchange for lease obligations		$ 1,041	$ 885	$ 887
[1]	On January 1, 2019, we adopted Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842),” which requires certain supplemental cash flow disclosures. Where these disclosures or a comparable figure were not required under the former lease standard, we have not retrospectively presented historical amounts. See Note 1 – Summary of Significant Accounting Policies for additional details.

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Cash Flows [Abstract]
Capitalized interest	$ 473	$ 362	$ 136

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - USD ($) $ in Millions		Total	Preferred Stock Outstanding	Common Stock Outstanding	Treasury Shares at Cost	Par Value and Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance, beginning of period at Dec. 31, 2016		$ 18,236			$ (1)	$ 38,846	$ 1	$ (20,610)
Common stock outstanding, beginning balance (in shares) at Dec. 31, 2016				826,357,331
Preferred stock outstanding, beginning balance (in shares) at Dec. 31, 2016			20,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		4,536						4,536
Other comprehensive (loss) income		7					7
Stock-based compensation		344				344
Exercise of stock options		19				19
Exercise of stock options (in shares)				450,493
Stock issued for employee stock purchase plan		82				82
Stock issued for employee stock purchase plan (in shares)				1,832,043
Issuance of vested restricted stock units (in shares)				8,338,271
Shares withheld related to net share settlement of stock awards and stock options		(166)				(166)
Shares withheld related to net share settlement of stock awards and stock options (in shares)				(2,754,721)
Mandatory conversion of preferred shares to common shares			(20,000,000)	32,237,983
Repurchases of common stock		$ (444)				(444)
Repurchases of common stock (in shares)		(7,010,889)		(7,010,889)
Transfer RSU from NQDC plan					(3)	3
Transfer RSU to NQDC plan (in shares)				(43,860)
Dividends on preferred stock		$ (55)				(55)
Preferred stock outstanding, ending balance (in shares) at Dec. 31, 2017			0
Balance, end of period at Dec. 31, 2017		22,559			(4)	38,629	8	(16,074)
Common stock outstanding, ending balance (in shares) at Dec. 31, 2017				859,406,651
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		2,888						2,888
Other comprehensive (loss) income		(332)					(332)
Stock-based compensation		473				473
Exercise of stock options		3				3
Exercise of stock options (in shares)				187,965
Stock issued for employee stock purchase plan		103				103
Stock issued for employee stock purchase plan (in shares)				2,011,794
Issuance of vested restricted stock units (in shares)				7,448,148
Issuance of restricted stock awards (in shares)				225,799
Shares withheld related to net share settlement of stock awards and stock options		(146)				(146)
Shares withheld related to net share settlement of stock awards and stock options (in shares)				(2,321,827)
Repurchases of common stock		$ (1,054)				(1,054)
Repurchases of common stock (in shares)		(16,738,758)		(16,738,758)
Transfer RSU from NQDC plan					(2)	2
Transfer RSU to NQDC plan (in shares)				(39,455)
Prior year Retained Earnings	[1]	$ 224					(8)	232
Preferred stock outstanding, ending balance (in shares) at Dec. 31, 2018			0
Balance, end of period at Dec. 31, 2018		$ 24,718			(6)	38,010	(332)	(12,954)
Common stock outstanding, ending balance (in shares) at Dec. 31, 2018		850,180,317		850,180,317
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		$ 3,468						3,468
Other comprehensive (loss) income		(536)					(536)
Stock-based compensation		517				517
Exercise of stock options		1				1
Exercise of stock options (in shares)				85,083
Stock issued for employee stock purchase plan		124				124
Stock issued for employee stock purchase plan (in shares)				2,091,650
Issuance of vested restricted stock units (in shares)				6,685,950
Forfeiture of restricted stock awards (in shares)				(24,682)
Shares withheld related to net share settlement of stock awards and stock options		(156)				(156)
Shares withheld related to net share settlement of stock awards and stock options (in shares)				(2,094,555)
Transfer RSU from NQDC plan					(2)	2
Transfer RSU to NQDC plan (in shares)				(18,363)
Prior year Retained Earnings	[1]	653						653
Preferred stock outstanding, ending balance (in shares) at Dec. 31, 2019			0
Balance, end of period at Dec. 31, 2019		$ 28,789			$ (8)	$ 38,498	$ (868)	$ (8,833)
Common stock outstanding, ending balance (in shares) at Dec. 31, 2019		856,905,400		856,905,400
[1]	Prior year Retained Earnings represents the impact of the adoption of new accounting standards on beginning Accumulated Deficit and Accumulated Other Comprehensive Loss. See Note 1 – Summary of Significant Accounting Policies for further information.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Note 1 – Summary of Significant Accounting Policies Description of Business T-Mobile US, Inc. (“T-Mobile,” “we,” “our,” “us” or the “Company”), together with its consolidated subsidiaries, is a leading provider of mobile communications services, including voice, messaging and data, under its flagship brands, T-Mobile and Metro™ by T-Mobile ("Metro by T-Mobile"), in the United States (“U.S.”), Puerto Rico and the U.S. Virgin Islands. All of our revenues were earned in, and all of our long-lived assets are located in, the U.S., Puerto Rico and the U.S. Virgin Islands. We provide mobile communications services primarily using our 4G Long-Term Evolution (“LTE”) network and our newly deployed 5G technology network. We also offer a wide selection of wireless devices, including handsets, tablets and other mobile communication devices, and accessories for sale, as well as financing through Equipment Installment Plans (“EIP”) and leasing through JUMP! On Demand™. Additionally, we provide reinsurance for handset insurance policies and extended warranty contracts offered to our mobile communications customers. Basis of Presentation The consolidated financial statements include the balances and results of operations of T-Mobile and our consolidated subsidiaries. We consolidate majority-owned subsidiaries over which we exercise control, as well as variable interest entities (“VIE”) where we are deemed to be the primary beneficiary and VIEs, which cannot be deconsolidated, such as those related to Tower obligations. Intercompany transactions and balances have been eliminated in consolidation. We operate as a single operating segment. The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires our management to make estimates and assumptions which affect the financial statements and accompanying notes. Estimates are based on historical experience, where applicable, and other assumptions which our management believes are reasonable under the circumstances. These estimates are inherently subject to judgment and actual results could differ from these estimates. Certain prior year amounts have been reclassified to conform to the current year's presentation. See “Accounting Pronouncements Adopted During the Current Year” below. Cash and Cash Equivalents Cash equivalents consist of highly liquid money market funds and U.S. Treasury securities with remaining maturities of three months or less at the date of purchase. Receivables and Allowance for Credit Losses Accounts receivable consist primarily of amounts currently due from customers, other carriers and third-party retail channels. Accounts receivable not held for sale are reported in the balance sheet at outstanding principal adjusted for any charge-offs and the allowance for credit losses. Accounts receivable held for sale are reported at the lower of amortized cost or fair value. We have an arrangement to sell the majority of service accounts receivable on a revolving basis, which are treated as sales of financial assets. We offer certain retail customers the option to pay for their devices and certain other purchases in installments typically over a period of 24, but up to 36, months using an EIP. EIP receivables not held for sale are reported in our Consolidated Balance Sheets at outstanding principal adjusted for any charge-offs, allowance for credit losses and unamortized discounts. At the time of an installment sale, we impute a discount for interest if the EIP term exceeds 12 months as there is no stated rate of interest on the EIP receivables. The EIP receivables are recorded at their present value, which is determined by discounting future cash payments at the imputed interest rate. The difference between the recorded amount of the EIP receivables and their unpaid principal balance (i.e., the contractual amount due from the customer) results in a discount which is allocated to the performance obligations in the arrangement and recorded as a reduction in transaction price in Total service revenues and Equipment revenues in our Consolidated Statements of Comprehensive Income. We determine the imputed discount rate based primarily on current market interest rates and the estimated credit risk on the EIP receivables. As a result, we do not recognize a separate credit loss allowance at the time of issuance as the effects of uncertainty about future cash flows resulting from credit risk are included in the initial present value measurement of the receivable. The imputed discount on EIP receivables is amortized over the financed installment term using the effective interest method and recognized as Other revenues in our Consolidated Statements of Comprehensive Income. Subsequent to the initial determination of the imputed discount, we assess the need for and, if necessary, recognize an allowance for credit losses to the extent the amount of estimated probable losses on the gross EIP receivable balances exceed the remaining unamortized imputed discount balances. Total imputed discount and allowances were approximately 7.0% and 8.1% of the total amount of gross accounts receivable, including EIP receivables, at December 31, 2019 and 2018, respectively. The current portion of the EIP receivables is included in Equipment installment plan receivables, net and the long-term portion of the EIP receivables is included in Equipment installment plan receivables due after one year, net in our Consolidated Balance Sheets. We have an arrangement to sell certain EIP receivables on a revolving basis, which are treated as sales of financial assets. We maintain an allowance for credit losses and determine its appropriateness through an established process that assesses the losses inherent in our receivables portfolio. We develop and document our allowance methodology at the portfolio segment level - accounts receivable portfolio and EIP receivable portfolio segments. While we attribute portions of the allowance to our respective accounts receivable and EIP portfolio segments, the entire allowance is available to absorb credit losses inherent in the total receivables portfolio. Our process involves procedures to appropriately consider the unique risk characteristics of our accounts receivable and EIP receivable portfolio segments. For each portfolio segment, losses are estimated collectively for groups of receivables with similar characteristics. Our allowance levels are influenced by receivable volumes, receivable delinquency status, historical loss experience and other conditions influencing loss expectations, such as macro-economic conditions. Inventories Inventories consist primarily of wireless devices and accessories, which are valued at the lower of cost or net realizable value. Cost is determined using standard cost which approximates average cost. Shipping and handling costs paid to wireless device and accessories vendors, and costs to refurbish used devices recovered through our device upgrade programs are included in the standard cost of inventory. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. We record inventory write-downs to net realizable value for obsolete and slow-moving items based on inventory turnover trends and historical experience. Long-Lived Assets Long-lived assets include assets that do not have indefinite lives, such as property and equipment and other intangible assets. All of our long-lived assets are located in the U.S., including Puerto Rico and the U.S. Virgin Islands. We assess potential impairments to our long-lived assets when events or changes in circumstances indicate the carrying amount of the asset may not be recoverable. If any indicators of impairment are present, we test recoverability. The carrying value of a long-lived asset or asset group is not recoverable if it exceeds the sum of the undiscounted cash flows expected to be generated from the use and eventual disposition of the asset or asset group. If the undiscounted cash flows do not exceed the asset or asset group’s carrying amount, then an impairment loss is recorded, measured as the amount by which the carrying amount of a long-lived asset or asset group exceeds its fair value. Property and Equipment Property and equipment consists of buildings and equipment, wireless communications systems, leasehold improvements, capitalized software, leased wireless devices and construction in progress. Buildings and equipment include certain network server equipment. Wireless communications systems include assets to operate our wireless network and IT data centers, including tower assets and leasehold improvements and assets related to the liability for the retirement of long-lived assets. Leasehold improvements include asset improvements other than those related to the wireless network. Property and equipment are recorded at cost less accumulated depreciation and impairments, if any, in Property and equipment, net on our Consolidated Balance Sheets. We generally depreciate property and equipment over the period the property and equipment provide economic benefit. Depreciable life studies are performed periodically to confirm the appropriateness of depreciable lives for certain categories of property and equipment. These studies take into account actual usage, physical wear and tear, replacement history and assumptions about technology evolution. When these factors indicate the useful life of an asset is different from the previous assessment, the remaining book value is depreciated prospectively over the adjusted remaining estimated useful life. Leasehold improvements are depreciated over the shorter of their estimated useful lives or the related lease term. JUMP! On Demand allows customers to lease a device over a period of up to 18 months and upgrade it for a new device up to one time per month. To date, all of our leased devices were classified as operating leases. At operating lease inception, leased wireless devices are transferred from inventory to property and equipment. Leased wireless devices are depreciated to their estimated residual value over the period expected to provide utility to us, which is generally shorter than the lease term and considers expected losses. Revenues associated with the leased wireless devices, net of incentives, are generally recognized over the lease term. Upon device upgrade or at lease end, customers must return or purchase their device. Returned devices transferred from Property and equipment, net are recorded as inventory and are valued at the lower of cost or net realizable value with any write-down recognized as Cost of equipment sales in our Consolidated Statements of Comprehensive Income. Costs of major replacements and improvements are capitalized. Repair and maintenance expenditures which do not enhance or extend the asset’s useful life are charged to operating expenses as incurred. Construction costs, labor and overhead incurred in the expansion or enhancement of our wireless network are capitalized. Capitalization commences with pre-construction period administrative and technical activities, which includes obtaining leases, zoning approvals and building permits, and ceases at the point at which the asset is ready for its intended use. We capitalize interest associated with the acquisition or construction of certain property and equipment. Capitalized interest is reported as a reduction in interest expense and depreciated over the useful life of the related assets. We record an asset retirement obligation for the fair value of legal obligations associated with the retirement of tangible long-lived assets and a corresponding increase in the carrying amount of the related asset in the period in which the obligation is incurred. In periods subsequent to initial measurement, we recognize changes in the liability resulting from the passage of time and revisions to either the timing or the amount of the original estimate. Over time, the liability is accreted to its present value and the capitalized cost is depreciated over the estimated useful life of the asset. Our obligations relate primarily to certain legal obligations to remediate leased property on which our network infrastructure and administrative assets are located. We capitalize certain costs incurred in connection with developing or acquiring internal use software. Capitalization of software costs commences once the final selection of the specific software solution has been made and management authorizes and commits to funding the software project. Capitalized software costs are included in Property and equipment, net in our Consolidated Balance Sheets and are amortized on a straight-line basis over the estimated useful life of the asset. Costs incurred during the preliminary project stage, as well as maintenance and training costs, are expensed as incurred. Other Intangible Assets Intangible assets that do not have indefinite useful lives are amortized over their estimated useful lives. Customer lists are amortized using the sum-of-the-years'-digits method over the expected period in which the relationship is expected to contribute to future cash flows. The remaining finite-lived intangible assets are amortized using the straight-line method. Goodwill and Indefinite-Lived Intangible Assets Goodwill Goodwill consists of the excess of the purchase price over the fair value of identifiable net assets acquired in a business combination. Goodwill is allocated to our two reporting units, wireless and Layer3. Spectrum Licenses Spectrum licenses are carried at costs incurred to acquire the spectrum licenses and the costs to prepare the spectrum licenses for their intended use, such as costs to clear acquired spectrum licenses. The Federal Communications Commission (“FCC”) issues spectrum licenses which provide us with the exclusive right to utilize designated radio frequency spectrum within specific geographic service areas to provide wireless communications services. While spectrum licenses are issued for a fixed period of time, typically for up to fifteen years, the FCC has granted license renewals routinely and at a nominal cost. The spectrum licenses held by us expire at various dates. We believe we will be able to meet all requirements necessary to secure renewal of our spectrum licenses at nominal costs. Moreover, we determined there are currently no legal, regulatory, contractual, competitive, economic or other factors that limit the useful lives of our spectrum licenses. Therefore, we determined the spectrum licenses should be treated as indefinite-lived intangible assets. At times, we enter into agreements to sell or exchange spectrum licenses. Upon entering into the arrangement, if the transaction has been deemed to have commercial substance, spectrum licenses are reviewed for impairment and transferred at their carrying value, net of any impairment, to assets held for sale included in Other current assets in our Consolidated Balance Sheets until approval and completion of the exchange or sale. Upon closing of the transaction, spectrum licenses acquired as part of an exchange of nonmonetary assets are valued at fair value and the difference between the fair value of the spectrum licenses obtained, book value of the spectrum licenses transferred and cash paid, if any, is recognized as a gain and included in Gains on disposal of spectrum licenses in our Consolidated Statements of Comprehensive Income. Our fair value estimates of spectrum licenses are based on information for which there is little or no observable market data. If the transaction lacks commercial substance or the fair value is not measurable, the acquired spectrum licenses are recorded at the book value of the assets transferred or exchanged. Impairment We assess the carrying value of our goodwill and other indefinite-lived intangible assets, such as our spectrum licenses, for potential impairment annually as of December 31, or more frequently if events or changes in circumstances indicate such assets might be impaired. When assessing goodwill for impairment we may elect to first perform a qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. If we do not perform a qualitative assessment, or if the qualitative assessment indicates it is more likely than not that the fair value of the two reporting units, wireless and Layer3, is less than its carrying amount, we perform a quantitative test. We recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized would not exceed the total amount of goodwill allocated to that reporting unit. We test our spectrum licenses for impairment on an aggregate basis, consistent with our management of the overall business at a national level. We may elect to first perform a qualitative assessment to determine whether it is more likely than not that the fair value of an intangible asset is less than its carrying value. If we do not perform the qualitative assessment, or if the qualitative assessment indicates it is more likely than not that the fair value of the intangible asset is less than its carrying amount, we calculate the estimated fair value of the intangible asset. If the estimated fair value of the spectrum licenses is lower than their carrying amount, an impairment loss is recognized for the difference. We estimate fair value using the Greenfield methodology, which is an income approach based on discounted cash flows associated with the intangible asset, to estimate the price at which an orderly transaction to sell the asset would take place between market participants at the measurement date under current market conditions. Guarantee Liabilities We offer a device trade-in program, Just Upgrade My Phone (“JUMP!”), which provides eligible customers a specified-price trade-in right to upgrade their device. Upon enrollment, participating customers must finance the purchase of a device on an EIP and have a qualifying T-Mobile monthly wireless service plan, which is treated as an arrangement with multiple performance obligations when entered into at or near the same time. Upon a qualifying JUMP! program upgrade, the customer’s remaining EIP balance is settled provided they trade-in their eligible used device in good working condition and purchase a new device from us on a new EIP. For customers who enroll in JUMP!, we recognize a liability and reduce revenue for the portion of revenue which represents the estimated fair value of the specified-price trade-in right guarantee. The guarantee liability is valued based on various economic and customer behavioral assumptions, which requires judgment, including estimating the customer's remaining EIP balance at trade-in, the expected fair value of the used device at trade-in, and the probability and timing of trade-in. When customers upgrade their device, the difference between the EIP balance credit to the customer and the fair value of the returned device is recorded against the guarantee liabilities. All assumptions are reviewed periodically. Fair Value Measurements We carry certain assets and liabilities at fair value. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three-tier hierarchy for inputs used in measuring fair value, which prioritizes the inputs based on the observability as of the measurement date, is as follows: Level 1 Quoted prices in active markets for identical assets or liabilities; Level 2 Observable inputs other than the quoted prices in active markets for identical assets and liabilities; and Level 3 Unobservable inputs for which there is little or no market data, which require us to develop assumptions of what market participants would use in pricing the asset or liability. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the placement of assets and liabilities being measured within the fair value hierarchy. The carrying values of cash and cash equivalents, short-term investments, accounts receivable, accounts receivable from affiliates and accounts payable approximate fair value due to the short-term maturities of these instruments. The carrying values of EIP receivables approximate fair value as the receivables are recorded at their present value, net of unamortized discount and allowance for credit losses. There were no financial instruments with a carrying value materially different from their fair value, based on quoted market prices or rates for the same or similar instruments, or internal valuation models. Derivative Financial Instruments Derivative financial instruments are recognized as either assets or liabilities and are measured at fair value. We do not use derivatives for trading or speculative purposes. For derivative instruments designated as cash flow hedges associated with forecasted debt issuances, changes in fair value are reported as a component of Accumulated other comprehensive loss until reclassified into Interest expense in the same period the hedged transaction affects earnings, generally over the life of the related debt. Unrealized gains on derivatives designated as cash flow hedges are recorded at fair value as assets, and unrealized losses on derivatives designated as cash flow hedges are recorded at fair value as liabilities. Revenue Recognition (effective January 1, 2018) We primarily generate our revenue from providing wireless services to customers and selling or leasing devices and accessories. Our contracts with customers may involve multiple performance obligations, which include wireless services, wireless devices or a combination thereof, and we allocate the transaction price between each performance obligation based on its relative standalone selling price. Significant Judgments The most significant judgments affecting the amount and timing of revenue from contracts with our customers include the following items: • Revenue for service contracts that we assess are not probable of collection is not recognized until the contract is completed or terminated and cash is received. Collectibility is re-assessed when there is a significant change in facts or circumstances. Our assessment of collectibility considers whether we may limit our exposure to credit risk through our right to stop transferring additional service in the event the customer is delinquent as well as certain contract terms such as down payments that reduce our exposure to credit risk. Customer credit behavior is inherently uncertain. See “Receivables and Allowance for Credit Losses”, above, for more discussion on how we assess credit risk. • Promotional EIP bill credits offered to a customer on an equipment sale that are paid over time and are contingent on the customer maintaining a service contract may result in an extended service contract based on whether a substantive penalty is deemed to exist. Determining whether contingent EIP bill credits result in a substantive termination penalty may require significant judgment. • The identification of distinct performance obligations within our service plans may require significant judgment. • Revenue is recorded net of costs paid to another party for performance obligations where we arrange for the other party to transfer goods or services to the customer (i.e., when we are acting as an agent). For example, performance obligations relating to services provided by third-party content providers where we neither control a right to the content provider’s service nor control the underlying service itself are presented net because we are acting as an agent. The determination of whether we control the underlying service or right to the service prior to our transfer to the customer requires, at times, significant judgment. • For transactions where we recognize a significant financing component, judgment is required to determine the discount rate. For EIP sales, the discount rate used to adjust the transaction price primarily reflects current market interest rates and the estimated credit risk of the customer. Customer credit behavior is inherently uncertain. See “Receivables and Allowance for Credit Losses”, above, for more discussion on how we assess credit risk. • Our products are generally sold with a right of return, which is accounted for as variable consideration when estimating the amount of revenue to recognize. Device return levels are estimated based on the expected value method as there are a large number of contracts with similar characteristics and the outcome of each contract is independent of the others. Historical return rate experience is a significant input to our expected value methodology. • Sales of equipment to indirect dealers who have been identified as our customer (referred to as the sell-in model) often include credits subsequently paid to the dealer as a reimbursement for any discount promotions offered to the end consumer. These credits (payments to a customer) are accounted for as variable consideration when estimating the amount of revenue to recognize from the sales of equipment to indirect dealers and are estimated based on historical experience and other factors, such as expected promotional activity. • The determination of the standalone selling price for contracts that involve more than one performance obligation may require significant judgment, such as when the selling price of a good or service is not readily observable. • For capitalized contract costs, determining the amortization period over which such costs are recognized as well as assessing the indicators of impairment may require significant judgment. Wireless Services Revenue We generate our wireless services revenues from providing access to, and usage of, our wireless communications network. Service revenues also include revenues earned for providing value added services to customers, such as handset insurance services. Service contracts are billed monthly either in advance or arrears, or are prepaid. Generally, service revenue is recognized as we satisfy our performance obligation to transfer service to our customers. We typically satisfy our stand-ready performance obligations, including unlimited wireless services, evenly over the contract term. For usage-based and prepaid wireless services, we satisfy our performance obligations when services are rendered. Consideration payable to a customer is treated as a reduction of the total transaction price, unless the payment is in exchange for a distinct good or service, such as certain commissions paid to dealers. Federal Universal Service Fund (“USF”) and other fees are assessed by various governmental authorities in connection with the services we provide to our customers and are included in Cost of services. When we separately bill and collect these regulatory fees from customers, they are recorded gross in Total service revenues in our Consolidated Statements of Comprehensive Income. For the years ended December 31, 2019, 2018 and 2017, we recorded approximately $93 million, $161 million and $258 million, respectively, of USF fees on a gross basis. We have made an accounting policy election to exclude from the measurement of the transaction price all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by us from a customer (e.g., sales, use, value added, and some excise taxes). Equipment Revenues We generate equipment revenues from the sale or lease of mobile communication devices and accessories. For performance obligations related to equipment contracts, we typically transfer control at a point in time when the device or accessory is delivered to, and accepted by, the customer or dealer. We have elected to account for shipping and handling activities that occur after control of the related good transfers as fulfillment activities instead of assessing such activities as performance obligations. We estimate variable consideration (e.g., device returns or certain payments to indirect dealers) primarily based on historical experience. Equipment sales not probable of collection are generally recorded as payments are received. Our assessment of collectibility considers contract terms such as down payments that reduce our exposure to credit risk. We offer certain customers the option to pay for devices and accessories in installments using an EIP. Generally, we recognize as a reduction of the total transaction price the effects of a financing component in contracts where customers purchase their devices and accessories on an EIP with a term of more than one year, including those financing components that are not considered to be significant to the contract. However, we have elected the practical expedient to not recognize the effects of a significant financing component for contracts where we expect, at contract inception, that the period between the transfer of a performance obligation to a customer and the customer’s payment for that performance obligation will be one year or less. In addition, for customers who enroll in our JUMP! program, we recognize a liability based on the estimated fair value of the specified-price trade-in right guarantee. The fair value of the guarantee is deducted from the transaction price and the remaining transaction price is allocated to other elements of the contract, including service and equipment performance obligations. See “Guarantee Liabilities” above for further information. JUMP! On Demand allows customers to lease a device over a period of up to 18 months and upgrade it for a new device up to one time per month. To date, all of our leased wireless devices are accounted for as operating leases and estimated contract consideration is allocated between lease elements and non-lease elements (such as service and equipment performance obligations) based on the relative standalone selling price of each performance obligation in the contract. Lease revenues are recorded as equipment revenues and recognized as earned on a straight-line basis over the lease term. Lease revenues on contracts not probable of collection are limited to the amount of payments received. See “Property and Equipment” above for further information. Contract Balances Generally, our devices and service plans are available at standard prices, which are maintained on price lists and published on our website and/or within our retail stores. For contracts that involve more than one product or service that are identified as separate performance obligations, the transaction price is allocated to the performance obligations based on their relative standalone selling prices. The standalone selling price is the price at which we would sell the good or service separately to a customer and is most commonly evidenced by the price at which we sell that good or service separately in similar circumstances and to similar customers. A contract asset is recorded when revenue is recognized in advance of our right to receive consideration (i.e., we must perform additional services in order to receive consideration). Amounts are recorded as receivables when our right to consideration is unconditional. When consideration is received, or we have an unconditional right to consideration in advance of delivery of goods or services, a contract liability is recorded. The transaction price can include non-refundable upfront fees, which are allocated to the identifiable performance obligations. Contract assets are included in Other current assets and Other assets and contract liabilities are included in Deferred revenue in our Consolidated Balance Sheets. Contract Modifications Our service contracts allow customers to frequently modify their contracts without incurring penalties in many cases. Each time a contract is modified, we evaluate the change in scope or price of the contract to determine if the modification should be treated as a separate contract, as if there is a termination of the existing contract and creation of a new contract, or if the modification should be considered a change associated with the existing contract. We typically do not have significant impacts from contract modifications. Contract Co

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Business Combinations	Note 2 – Business Combinations Proposed Sprint Transactions On April 29, 2018, we entered into a Business Combination Agreement to merge with Sprint in an all-stock transaction at a fixed exchange ratio of 0.10256 shares of T-Mobile common stock for each share of Sprint common stock, or 9.75 shares of Sprint common stock for each share of T-Mobile common stock (the “Merger”). The combined company will be named “T-Mobile” and, as a result of the Merger, is expected to be able to rapidly launch a broad and deep nationwide 5G network, accelerate innovation and increase competition in the U.S. wireless, video and broadband industries. Neither T-Mobile nor Sprint on its own could generate comparable benefits to consumers. The Merger and the other transactions contemplated by the Business Combination Agreement (collectively, the “Transactions”) have been approved by the boards of directors of T-Mobile and Sprint and the required approvals of the stockholders of each of T-Mobile and Sprint have been obtained. Immediately following the Merger, it is anticipated that Deutsche Telekom AG (“DT”) and SoftBank Group Corp. (“SoftBank”) will hold, directly or indirectly, on a fully diluted basis, approximately 41.5% and 27.2%, respectively, of the outstanding T-Mobile common stock, with the remaining approximately 31.3% of the outstanding T-Mobile common stock held by other stockholders, based on closing share prices and certain other assumptions as of December 31, 2019. In connection with the entry into the Business Combination Agreement, T-Mobile USA, Inc. (“T-Mobile USA”) entered into commitment letter, dated as of April 29, 2018 (as amended and restated on May 15, 2018 and on September 6, 2019, the “Commitment Letter”). The funding of the debt facilities provided for in the Commitment Letter is subject to the satisfaction of the conditions set forth therein, including consummation of the Merger. The proceeds of the debt financing provided for in the Commitment Letter will be used to refinance certain existing debt of us, Sprint and our and Sprint’s respective subsidiaries and for post-closing working capital needs of the combined company. See Note 8 – Debt for further information. In connection with the entry into the Business Combination Agreement, DT and T-Mobile USA entered into a Financing Matters Agreement, dated as of April 29, 2018 (the “Financing Matters Agreement”), pursuant to which DT agreed, among other things, to consent to, subject to certain conditions, certain amendments to certain existing debt owed to DT, in connection with the Merger. If the Merger is consummated, we will make payments for requisite consents to DT of $13 million. There was no payment accrued as of December 31, 2019. See Note 8 – Debt for further information. On May 18, 2018, under the terms and conditions described in the Consent Solicitation Statement dated as of May 14, 2018 (the "Consent Solicitation Statement"), we obtained consents necessary to effect certain amendments to certain existing debt of us and our subsidiaries. If the Merger is consummated, we will make payments for requisite consents to third-party note holders of $95 million. There were no consent payments accrued as of December 31, 2019. Under the terms of the Business Combination Agreement, if the Business Combination Agreement is terminated, Sprint may be required to reimburse us for 33% of the consent, bank, and other fees we paid or accrued, which totaled $18 million as of December 31, 2019. There were no reimbursements accrued as of December 31, 2019. Sprint also obtained consents necessary to effect certain amendments to certain existing debt of Sprint and its subsidiaries. In connection with receiving the requisite consents, Sprint made upfront payments to third-party note holders and related bank fees of $242 million. Under the terms of the Business Combination Agreement, if the Business Combination Agreement is terminated, we may also be required to reimburse Sprint for 67% of the upfront consent and related bank fees it paid, which totaled $162 million as of December 31, 2019. There were no fees accrued as of December 31, 2019. We recognized Merger-related costs of $620 million and $196 million for the years ended December 31, 2019 and 2018, respectively. These costs generally included consulting and legal fees and were recognized as Selling, general and administrative expenses in our Consolidated Statements of Comprehensive Income. Payments for Merger-related costs were $442 million and $86 million for the years ended December 31, 2019 and 2018, respectively, and were recognized within Net cash provided by operating activities in our Consolidated Statements of Cash Flows. The Business Combination Agreement contains certain termination rights for both Sprint and us. If we terminate the Business Combination Agreement in connection with a failure to satisfy the closing condition related to specified minimum credit ratings for the combined company on the closing date of the Merger (after giving effect to the Merger) from at least two of the three credit rating agencies, then in certain circumstances, we may be required to pay Sprint an amount equal to $600 million. On June 18, 2018, we filed a Public Interest Statement and applications for approval of the Merger with the FCC. On July 18, 2018, the FCC issued a Public Notice formally accepting our applications and establishing a period for public comment. On May 20, 2019, to facilitate the FCC’s review and approval of the FCC license transfers associated with the proposed Merger, we and Sprint filed with the FCC a written ex parte presentation (the “Presentation”) relating to the proposed Merger. The Presentation included proposed commitments from us and Sprint. The FCC approved the Merger on November 5, 2019. On June 11, 2019, a number of state attorneys general filed a lawsuit against us, DT, Sprint, and SoftBank in the U.S. District Court for the Southern District of New York, alleging that the Merger, if consummated, would violate Section 7 of the Clayton Act and so should be enjoined. After it was filed, several additional states joined the lawsuit. Of the states that joined the lawsuit, two have subsequently withdrawn from the suit having resolved their concerns with the Merger. We believe the plaintiffs’ claims are without merit, and have defended the case vigorously. Trial concluded after two weeks of witness testimony and presentation of document evidence. We are now waiting for the trial court’s ruling. On November 25, 2019, individual consumers filed a similar lawsuit in the Northern District of California. That case has been stayed pending the outcome of the New York litigation. On July 26, 2019, we entered into an Asset Purchase Agreement (the “Asset Purchase Agreement”) with Sprint and DISH Network Corporation (“DISH”). We and Sprint are collectively referred to as the “Sellers.” Pursuant to the Asset Purchase Agreement, upon the terms and subject to the conditions thereof, following the consummation of the Merger, DISH will acquire Sprint’s prepaid wireless business, currently operated under the Boost Mobile and Sprint prepaid brands (excluding the Assurance brand Lifeline customers and the prepaid wireless customers of Shenandoah Telecommunications Company and Swiftel Communications, Inc.), including customer accounts, inventory, contracts, intellectual property and certain other specified assets (the “Prepaid Business”), and will assume certain related liabilities (the “Prepaid Transaction”). DISH will pay the Sellers $1.4 billion for the Prepaid Business, subject to a working capital adjustment. The consummation of the Prepaid Transaction is subject to the consummation of the Merger and other customary closing conditions. At the closing of the Prepaid Transaction, the Sellers and DISH will enter into (i) a License Purchase Agreement pursuant to which (a) the Sellers will sell certain 800 MHz spectrum licenses held by Sprint to DISH for a total of approximately $3.6 billion in a transaction to be completed, subject to certain additional closing conditions, following an application for FCC approval to be filed three years following the closing of the Merger and (b) the Sellers will have the option to lease back from DISH, as needed, a portion of the spectrum sold for an additional two years following the closing of the spectrum sale transaction, (ii) a Transition Services Agreement providing for the Sellers’ provision of transition services to DISH in connection with the Prepaid Business for a period of up to three years following the closing of the Prepaid Transaction, (iii) a Master Network Services Agreement providing for the Sellers’ provision of network services to customers of the Prepaid Business for a period of up to seven years following the closing of the Prepaid Transaction, and (iv) an Option to Acquire Tower and Retail Assets offering DISH the option to acquire certain decommissioned towers and retail locations from the Sellers, subject to obtaining all necessary third-party consents, for a period of up to five years following the closing of the Prepaid Transaction. On July 26, 2019, in connection with the entry into the Asset Purchase Agreement, we and the other parties to the Business Combination Agreement entered into Amendment No. 1 (the “Amendment”) to the Business Combination Agreement. The Amendment extended the Outside Date (as defined in the Business Combination Agreement) to November 1, 2019, or, if the Marketing Period (as defined in the Business Combination Agreement) had started and was in effect at such date, then January 2, 2020. Because the Transactions were not completed by the Outside Date, each of T-Mobile and Sprint currently has the right to terminate the Business Combination Agreement or the terms may be amended. On July 26, 2019, the U.S. Department of Justice (the “DOJ”) filed a complaint and a proposed final judgment (the “Proposed Consent Decree”) agreed to by us, DT, Sprint, SoftBank and DISH with the U.S. District Court for the District of Columbia. The Proposed Consent Decree would fully resolve DOJ’s investigation into the Merger and would require the parties to, among other things, carry out the divestitures to be made pursuant to the Asset Purchase Agreement described above upon closing of the Merger. The Proposed Consent Decree is subject to judicial approval. The consummation of the Merger remains subject to certain closing conditions. We expect the Merger will be permitted to close in early 2020.

Receivables and Allowance for C

Receivables and Allowance for Credit Losses	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Receivables and Allowance for Credit Losses	Note 3 – Receivables and Allowance for Credit Losses Our portfolio of receivables is comprised of two portfolio segments: accounts receivable and EIP receivables. Our accounts receivable segment primarily consists of amounts currently due from customers, including service and leased device receivables, other carriers and third-party retail channels. Based upon customer credit profiles, we classify the EIP receivables segment into two customer classes of “Prime” and “Subprime.” Prime customer receivables are those with lower delinquency risk and Subprime customer receivables are those with higher delinquency risk. Customers may be required to make a down payment on their equipment purchases. In addition, certain customers within the Subprime category are required to pay an advance deposit. To determine a customer’s credit profile, we use a proprietary credit scoring model that measures the credit quality of a customer using several factors, such as credit bureau information, consumer credit risk scores and service and device plan characteristics. The following table summarizes the EIP receivables, including imputed discounts and related allowance for credit losses: (in millions) December 31, 2019 December 31, 2018 EIP receivables, gross $ 4,582 $ 4,534 Unamortized imputed discount (299) (330) EIP receivables, net of unamortized imputed discount 4,283 4,204 Allowance for credit losses (100) (119) EIP receivables, net $ 4,183 $ 4,085 Classified on the balance sheet as: Equipment installment plan receivables, net $ 2,600 $ 2,538 Equipment installment plan receivables due after one year, net 1,583 1,547 EIP receivables, net $ 4,183 $ 4,085 To determine the appropriate level of the allowance for credit losses, we consider a number of credit quality factors, including historical credit losses and timely payment experience as well as current collection trends such as write-off frequency and severity, aging of the receivable portfolio, credit quality of the customer base and other qualitative factors such as macro-economic conditions. We write off account balances if collection efforts are unsuccessful and the receivable balance is deemed uncollectible, based on factors such as customer credit ratings and the length of time from the original billing date. For EIP receivables, subsequent to the initial determination of the imputed discount, we assess the need for and, if necessary, recognize an allowance for credit losses to the extent the amount of estimated incurred losses on the gross EIP receivable balances exceed the remaining unamortized imputed discount balances. The EIP receivables had weighted average effective imputed interest rates of 8.8% and 10.0% as of December 31, 2019, and 2018, respectively. Activity for the years ended December 31, 2019, 2018 and 2017, in the allowance for credit losses and unamortized imputed discount balances for the accounts receivable and EIP receivables segments were as follows: December 31, 2019 December 31, 2018 December 31, 2017 (in millions) Accounts Receivable Allowance EIP Receivables Allowance Total Accounts Receivable Allowance EIP Receivables Allowance Total Accounts Receivable Allowance EIP Receivables Allowance Total Allowance for credit losses and imputed discount, beginning of period $ 67 $ 449 $ 516 $ 86 $ 396 $ 482 $ 102 $ 316 $ 418 Bad debt expense 77 230 307 69 228 297 104 284 388 Write-offs, net of recoveries (83) (249) (332) (88) (240) (328) (120) (273) (393) Change in imputed discount on short-term and long-term EIP receivables N/A 136 136 N/A 250 250 N/A 252 252 Impact on the imputed discount from sales of EIP receivables N/A (167) (167) N/A (185) (185) N/A (183) (183) Allowance for credit losses and imputed discount, end of period $ 61 $ 399 $ 460 $ 67 $ 449 $ 516 $ 86 $ 396 $ 482 Management considers the aging of receivables to be an important credit indicator. The following table provides delinquency status for the unpaid principal balance for receivables within the EIP portfolio segment, which we actively monitor as part of our current credit risk management practices and policies: December 31, 2019 December 31, 2018 (in millions) Prime Subprime Total EIP Receivables, gross Prime Subprime Total EIP Receivables, gross Current - 30 days past due $ 2,384 $ 2,108 $ 4,492 $ 1,987 $ 2,446 $ 4,433 31 - 60 days past due 13 28 41 15 32 47 61 - 90 days past due 7 17 24 6 19 25 More than 90 days past due 7 18 25 7 22 29 Total receivables, gross $ 2,411 $ 2,171 $ 4,582 $ 2,015 $ 2,519 $ 4,534

Sales of Certain Receivables

Sales of Certain Receivables	12 Months Ended
	Dec. 31, 2019
Transfers and Servicing [Abstract]
Sales of Certain Receivables	Note 4 – Sales of Certain Receivables We have entered into transactions to sell certain service and EIP receivables. The transactions, including our continuing involvement with the sold receivables and the respective impacts to our Consolidated Financial Statements, are described below. Sales of Service Accounts Receivable Overview of the Transaction In 2014, we entered into an arrangement to sell certain service accounts receivable on a revolving basis (the “service receivable sale arrangement”). The maximum funding commitment of the service receivable sale arrangement is $950 million. In February 2019, the service receivable sale arrangement was amended to extend the scheduled expiration date, as well as certain third-party credit support under the arrangement, to March 2021. As of December 31, 2019 and 2018, the service receivable sale arrangement provided funding of $924 million and $774 million, respectively. Sales of receivables occur daily and are settled on a monthly basis. The receivables consist of service charges currently due from customers and are short-term in nature. In connection with the service receivable sale arrangement, we formed a wholly-owned subsidiary, which qualifies as a bankruptcy remote entity, to sell service accounts receivable (the “Service BRE”). The Service BRE does not qualify as a VIE, and due to the significant level of control we exercise over the entity, it is consolidated. Pursuant to the service receivable sale arrangement, certain of our wholly-owned subsidiaries transfer selected receivables to the Service BRE. The Service BRE then sells the receivables to an unaffiliated entity (the “Service VIE”), which was established to facilitate the sale of beneficial ownership interests in the receivables to certain third parties. Variable Interest Entity We determined that the Service VIE qualifies as a VIE as it lacks sufficient equity to finance its activities. We have a variable interest in the Service VIE but are not the primary beneficiary as we lack the power to direct the activities that most significantly impact the Service VIE’s economic performance. Those activities include committing the Service VIE to legal agreements to purchase or sell assets, selecting which receivables are purchased in the service receivable sale arrangement, determining whether the Service VIE will sell interests in the purchased service receivables to other parties, funding of the entity and servicing of receivables. We do not hold the power to direct the key decisions underlying these activities. For example, while we act as the servicer of the sold receivables, which is considered a significant activity of the Service VIE, we are acting as an agent in our capacity as the servicer and the counterparty to the service receivable sale arrangement has the ability to remove us as the servicing agent of the receivables at will with no recourse available to us. As we have determined we are not the primary beneficiary, the balances and results of the Service VIE are not included in our Consolidated Financial Statements. The following table summarizes the carrying amounts and classification of assets, which consists primarily of the deferred purchase price and liabilities included in our Consolidated Balance Sheets that relate to our variable interest in the Service VIE: (in millions) December 31, 2019 December 31, 2018 Other current assets $ 350 $ 339 Accounts payable and accrued liabilities 25 59 Other current liabilities 342 149 Sales of EIP Receivables Overview of the Transaction In 2015, we entered into an arrangement to sell certain EIP accounts receivable on a revolving basis (the “EIP sale arrangement”). The maximum funding commitment of the EIP sale arrangement is $1.3 billion, and the scheduled expiration date is November 2020. As of both December 31, 2019 and 2018, the EIP sale arrangement provided funding of $1.3 billion. Sales of EIP receivables occur daily and are settled on a monthly basis. In connection with this EIP sale arrangement, we formed a wholly-owned subsidiary, which qualifies as a bankruptcy remote entity (the “EIP BRE”). Pursuant to the EIP sale arrangement, our wholly-owned subsidiary transfers selected receivables to the EIP BRE. The EIP BRE then sells the receivables to a non-consolidated and unaffiliated third-party entity for which we do not exercise any level of control, nor does the third-party entity qualify as a VIE. Variable Interest Entity We determined that the EIP BRE is a VIE as its equity investment at risk lacks the obligation to absorb a certain portion of its expected losses. We have a variable interest in the EIP BRE and determined that we are the primary beneficiary based on our ability to direct the activities which most significantly impact the EIP BRE’s economic performance. Those activities include selecting which receivables are transferred into the EIP BRE and sold in the EIP sale arrangement and funding of the EIP BRE. Additionally, our equity interest in the EIP BRE obligates us to absorb losses and gives us the right to receive benefits from the EIP BRE that could potentially be significant to the EIP BRE. Accordingly, we include the balances and results of operations of the EIP BRE in our Consolidated Financial Statements. The following table summarizes the carrying amounts and classification of assets, which consists primarily of the deferred purchase price, and liabilities included in our Consolidated Balance Sheets that relate to the EIP BRE: (in millions) December 31, 2019 December 31, 2018 Other current assets $ 344 $ 321 Other assets 89 88 Other long-term liabilities 18 22 In addition, the EIP BRE is a separate legal entity with its own separate creditors who will be entitled, prior to any liquidation of the EIP BRE, to be satisfied prior to any value in the EIP BRE becoming available to us. Accordingly, the assets of the EIP BRE may not be used to settle our general obligations and creditors of the EIP BRE have limited recourse to our general credit. Sales of Receivables The transfers of service receivables and EIP receivables to the non-consolidated entities are accounted for as sales of financial assets. Once identified for sale, the receivable is recorded at the lower of cost or fair value. Upon sale, we derecognize the net carrying amount of the receivables. We recognize the cash proceeds received upon sale in Net cash provided by operating activities in our Consolidated Statements of Cash Flows. We recognize proceeds net of the deferred purchase price, consisting of a receivable from the purchasers that entitles us to certain collections on the receivables. We recognize the collection of the deferred purchase price in Net cash used in investing activities in our Consolidated Statements of Cash Flows as Proceeds related to beneficial interests in securitization transactions. The deferred purchase price represents a financial asset that is primarily tied to the creditworthiness of the customers and which can be settled in such a way that we may not recover substantially all of our recorded investment, due to default by the customers on the underlying receivables. We elected, at inception, to measure the deferred purchase price at fair value with changes in fair value included in Selling, general and administrative expense in our Consolidated Statements of Comprehensive Income. The fair value of the deferred purchase price is determined based on a discounted cash flow model which uses primarily unobservable inputs (Level 3 inputs), including customer default rates. As of December 31, 2019, and 2018, our deferred purchase price related to the sales of service receivables and EIP receivables was $781 million and $746 million, respectively. The following table summarizes the impact of the sale of certain service receivables and EIP receivables in our Consolidated Balance Sheets: (in millions) December 31, 2019 December 31, 2018 Derecognized net service receivables and EIP receivables $ 2,584 $ 2,577 Other current assets 694 660 of which, deferred purchase price 692 658 Other long-term assets 89 88 of which, deferred purchase price 89 88 Accounts payable and accrued liabilities 25 59 Other current liabilities 342 149 Other long-term liabilities 18 22 Net cash proceeds since inception 1,944 1,879 Of which: Change in net cash proceeds during the year-to-date period 65 (179) Net cash proceeds funded by reinvested collections 1,879 2,058 We recognized losses from sales of receivables, including adjustments to the receivables’ fair values and changes in fair value of the deferred purchase price, of $130 million, $157 million and $299 million for the years ended December 31, 2019, 2018 and 2017, respectively, in Selling, general and administrative expense in our Consolidated Statements of Comprehensive Income. Continuing Involvement Pursuant to the sale arrangements described above, we have continuing involvement with the service receivables and EIP receivables we sell as we service the receivables and are required to repurchase certain receivables, including ineligible receivables, aged receivables and receivables where write-off is imminent. We continue to service the customers and their related receivables, including facilitating customer payment collection, in exchange for a monthly servicing fee. As the receivables are sold on a revolving basis, the customer payment collections on sold receivables may be reinvested in new receivable sales. While servicing the receivables, we apply the same policies and procedures to the sold receivables as we apply to our owned receivables, and we continue to maintain normal relationships with our customers. Pursuant to the EIP sale arrangement, under certain circumstances, we are required to deposit cash or replacement EIP receivables primarily for contracts terminated by customers under our JUMP! Program. In addition, we have continuing involvement with the sold receivables as we may be responsible for absorbing additional credit losses pursuant to the sale arrangements. Our maximum exposure to loss related to the involvement with the service receivables and EIP receivables sold under the sale arrangements was $1.1 billion as of December 31, 2019. The maximum exposure to loss, which is a required disclosure under U.S. GAAP, represents an estimated loss that would be incurred under severe, hypothetical circumstances whereby we would not receive the deferred purchase price portion of the contractual proceeds withheld by the purchasers and would also be required to repurchase the maximum amount of receivables pursuant to the sale arrangements without consideration for any recovery. We believe the probability of these circumstances occurring is remote and the maximum exposure to loss is not an indication of our expected loss.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment	Note 5 – Property and Equipment The components of property and equipment were as follows: (in millions) Useful Lives December 31, 2019 December 31, 2018 Buildings and equipment Up to 40 years $ 2,587 $ 2,428 Wireless communications systems Up to 20 years 34,353 35,282 Leasehold improvements Up to 12 years 1,345 1,299 Capitalized software Up to 10 years 12,705 11,712 Leased wireless devices Up to 18 months 1,139 1,159 Construction in progress 2,973 2,776 Accumulated depreciation and amortization (33,118) (31,297) Property and equipment, net $ 21,984 $ 23,359 We capitalize interest associated with the acquisition or construction of certain property and equipment and spectrum intangible assets. We recognized capitalized interest of $473 million, $362 million and $136 million for the years ended December 31, 2019, 2018 and 2017, respectively. In December 2019, we sold 168 T-Mobile-owned wireless communications tower sites to an unrelated third party in exchange for net proceeds of $38 million which are included in Proceeds from sales of tower sites within Net cash used in investing activities in our Consolidated Statements of Cash Flows. A gain of $13 million was recognized as a reduction in Cost of services, exclusive of depreciation and amortization, in our Consolidated Statements of Comprehensive Income. We lease back space at certain of the sold tower sites for an initial term of ten years, followed by optional renewals. Total depreciation expense relating to property and equipment was $6.0 billion, $6.4 billion and $5.8 billion for the years ended December 31, 2019, 2018 and 2017, respectively. Included in the total depreciation expense for the years ended December 31, 2019, 2018 and 2017 was $543 million, $940 million and $1.0 billion, respectively, related to leased wireless devices. Asset retirement obligations are primarily for certain legal obligations to remediate leased property on which our network infrastructure and administrative assets are located. Activity in our asset retirement obligations was as follows: (in millions) December 31, 2019 December 31, 2018 Asset retirement obligations, beginning of year $ 609 $ 562 Liabilities incurred 35 26 Liabilities settled (2) (9) Accretion expense 32 30 Changes in estimated cash flows (15) — Asset retirement obligations, end of year $ 659 $ 609 Classified on the balance sheet as: Other long-term liabilities $ 659 $ 609 The corresponding assets, net of accumulated depreciation, related to asset retirement obligations were $159 million and $194 million as of December 31, 2019 and 2018, respectively.

Goodwill, Spectrum License Tran

Goodwill, Spectrum License Transactions and Other Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Spectrum License Transactions and Other Intangible Assets	Note 6 – Goodwill, Spectrum License Transactions and Other Intangible Assets Goodwill The changes in the carrying amount of goodwill for the years ended December 31, 2019 and 2018, are as follows: (in millions) Goodwill Historical goodwill $ 12,449 Goodwill from acquisition of Layer3 TV 218 Accumulated impairment losses at December 31, 2018 (10,766) Balance as of December 31, 2018 1,901 Goodwill from acquisition in 2019 29 Balance as of December 31, 2019 $ 1,930 Accumulated impairment losses at December 31, 2019 $ (10,766) In July 2019, we completed our acquisition of a mobile marketing company, for cash consideration of $32 million. Upon closing of the transaction, the acquired company became a wholly-owned consolidated subsidiary to T-Mobile. We recorded Goodwill of approximately $29 million, calculated as the excess of the purchase price paid over the fair value of net assets acquired. The acquired goodwill was allocated to our wireless reporting unit and will be tested for impairment at this level. The assets acquired and liabilities assumed were not material to our Consolidated Balance Sheets. The financial results from the acquisition closing date through December 31, 2019 were not material to our Consolidated Statements of Comprehensive Income. The acquisition was not material to our prior period consolidated results on a pro forma basis. Spectrum Licenses The following table summarizes our spectrum license activity for the years ended December 31, 2019 and 2018: (in millions) 2019 2018 Spectrum licenses, beginning of year $ 35,559 $ 35,366 Spectrum license acquisitions 857 138 Spectrum licenses transferred to held for sale — (1) Costs to clear spectrum 49 56 Spectrum licenses, end of year $ 36,465 $ 35,559 The following is a summary of significant spectrum transactions for the year ended December 31, 2019: • In June 2019, the FCC announced that we were the winning bidder of 2,211 licenses in the 24 GHz and 28 GHz spectrum auctions for an aggregate price of $842 million. • At the inception of the 28 GHz spectrum auction in October 2018, we deposited $20 million with the FCC. Upon conclusion of the 28 GHz spectrum auction in February 2019, we made an additional payment of $19 million for the purchase price of licenses won in the auction. • At the inception of the 24 GHz spectrum auction in February 2019, we deposited $147 million with the FCC. Upon conclusion of the 24 GHz spectrum auction in June 2019, we made an additional payment of $656 million for the purchase price of licenses won in the auction. The licenses are included in Spectrum licenses as of December 31, 2019, in our Consolidated Balance Sheets. Cash payments to acquire spectrum licenses and payments for costs to clear spectrum are included in Purchases of spectrum licenses and other intangible assets, including deposits in our Consolidated Statements of Cash Flows for the year ended December 31, 2019. The following is a summary of significant spectrum transactions for the year ended December 31, 2018: • We recorded spectrum licenses received as part of our acquisition of the remaining equity interest in Iowa Wireless Services, LLC, at their estimated fair value of approximately $87 million. • We closed on multiple spectrum purchase agreements in which we acquired total spectrum licenses of approximately $50 million for cash consideration. • In 2018, we signed a reciprocal long-term lease arrangement with Sprint in which both parties have the right to use a portion of spectrum owned by the other party. This executory agreement does not qualify as an acquisition of spectrum licenses, and we have not capitalized amounts related to the lease. The reciprocal long-term lease is a distinct transaction from the Merger. Goodwill and Other Intangible Assets Impairment Assessments Our impairment assessment of goodwill and other indefinite-lived intangible assets (spectrum licenses) resulted in no impairment as of December 31, 2019 and 2018. Other Intangible Assets The components of Other intangible assets were as follows: Useful Lives December 31, 2019 December 31, 2018 (in millions) Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Customer lists Up to 6 years $ 1,104 $ (1,104) $ — $ 1,104 $ (1,086) $ 18 Trademarks and patents Up to 19 years 323 (258) 65 312 (225) 87 Other Up to 28 years 100 (50) 50 149 (56) 93 Other intangible assets $ 1,527 $ (1,412) $ 115 $ 1,565 $ (1,367) $ 198 Amortization expense for intangible assets subject to amortization was $82 million, $124 million and $163 million for the years ended December 31, 2019, 2018 and 2017, respectively. The estimated aggregate future amortization expense for intangible assets subject to amortization are summarized below: (in millions) Estimated Future Amortization Year Ending December 31, 2020 $ 83 2021 14 2022 3 2023 3 2024 3 Thereafter 9 Total $ 115

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 7 – Fair Value Measurements The carrying values of Cash and cash equivalents, Accounts receivable, Accounts receivable from affiliates, Accounts payable and accrued liabilities, borrowings under vendor financing arrangements with our primary network equipment suppliers, and borrowings under our revolving credit facility with DT, our majority stockholder, approximate fair value due to the short-term maturities of these instruments. Derivative Financial Instruments Interest rate lock derivatives Periodically, we use derivatives to manage exposure to market risk, such as interest rate risk. We designated certain derivatives as hedging instruments in a qualifying hedge accounting relationship (cash flow hedge) to help minimize significant, unplanned fluctuations in cash flows caused by interest rate volatility. We do not use derivatives for trading or speculative purposes. We record interest rate lock derivatives on our Consolidated Balance Sheets at fair value that is derived primarily from observable market data, including yield curves. Interest rate lock derivatives were classified as Level 2 in the fair value hierarchy. Cash flows associated with qualifying hedge derivative instruments are presented in the same category on the Consolidated Statements of Cash Flows as the item being hedged. In October 2018, we entered into interest rate lock derivatives with notional amounts of $9.6 billion. The fair value of interest rate lock derivatives was a liability of $1.2 billion and $447 million as of December 31, 2019 and 2018, respectively, and was included in Other current liabilities in our Consolidated Balance Sheets. As of the years ended December 31, 2019 and 2018, no amounts were accrued or amortized into Interest expense in the Consolidated Statements of Comprehensive Income. Aggregate changes in fair value, net of tax, of $868 million and $332 million are presented in Accumulated other comprehensive loss as of December 31, 2019, and 2018, respectively. In November 2019, we extended the mandatory termination date on our interest rate lock derivatives to June 3, 2020. In December 2019, we made net collateral transfers to certain of our derivative counterparties totaling $632 million, which included variation margin transfers to (or from) such derivative counterparties based on daily market movements. These collateral transfers are included in Other current assets in our Consolidated Balance Sheets and in Net cash related to derivative contracts under collateral exchange arrangements within Net cash used in investing activities in our Consolidated Statements of Cash Flows. The interest rate lock derivatives will be settled upon the earlier of the issuance of fixed-rate debt or the mandatory termination date. Upon settlement of the interest rate lock derivatives, we will receive, or make, a cash payment in the amount of the fair value of the cash flow hedge as of the settlement date. Embedded derivatives In connection with our business combination with MetroPCS, we issued senior reset notes to DT. We determined certain components of the reset feature are required to be bifurcated from the senior reset notes and separately accounted for as embedded derivative instruments. The interest rates on our senior reset notes to DT were adjusted at the reset dates to rates defined in the applicable supplemental indentures to manage interest rate risk related to the senior reset notes. Our embedded derivatives are recorded at fair value primarily based on unobservable inputs and were classified as Level 3 in the fair value hierarchy for 2019 and 2018. Effective April 28, 2019, we redeemed $600 million aggregate principal amount of our 9.332% Senior Reset Notes due 2023 held by DT. The notes were redeemed at a redemption price equal to 104.666% of the principal amount of the notes (plus accrued and unpaid interest thereon) and were paid on April 29, 2019. The write-off of embedded derivatives upon redemption of the DT Senior Reset Notes resulted in a gain of $11 million and is included in Other expense, net in our Consolidated Statements of Comprehensive Income. The fair value of embedded derivative instruments was $19 million as of December 31, 2018, and is included in Other long-term liabilities in our Consolidated Balance Sheets. For the years ended December 31, 2019, 2018, and 2017, we recognized $8 million, $29 million and $52 million from the gain activity related to embedded derivatives instruments in Interest expense to affiliates in our Consolidated Statements of Comprehensive Income. Deferred Purchase Price Assets In connection with the sales of certain service and EIP accounts receivable pursuant to the sale arrangements, we have deferred purchase price assets measured at fair value that are based on a discounted cash flow model using unobservable Level 3 inputs, including customer default rates. See Note 4 – Sales of Certain Receivables for further information. The carrying amounts and fair values of our assets measured at fair value on a recurring basis included in our Consolidated Balance Sheets were as follows: Level within the Fair Value Hierarchy December 31, 2019 December 31, 2018 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Assets: Deferred purchase price assets 3 $ 781 $ 781 $ 746 $ 746 Long-term Debt The fair value of our Senior Notes to third parties was determined based on quoted market prices in active markets, and therefore was classified as Level 1 within the fair value hierarchy. The fair values of our Senior Notes to affiliates, Incremental Term Loan Facility to affiliates and Senior Reset Notes to affiliates were determined based on a discounted cash flow approach using market interest rates of instruments with similar terms and maturities and an estimate for our standalone credit risk. Accordingly, our Senior Notes to affiliates, Incremental Term Loan Facility to affiliates and Senior Reset Notes to affiliates were classified as Level 2 within the fair value hierarchy. Although we have determined the estimated fair values using available market information and commonly accepted valuation methodologies, considerable judgment was required in interpreting market data to develop fair value estimates for the Senior Notes to affiliates, Incremental Term Loan Facility to affiliates and Senior Reset Notes to affiliates. The fair value estimates were based on information available as of December 31, 2019, and 2018. As such, our estimates are not necessarily indicative of the amount we could realize in a current market exchange. The carrying amounts and fair values of our short-term and long-term debt included in our Consolidated Balance Sheets were as follows: Level within the Fair Value Hierarchy December 31, 2019 December 31, 2018 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Liabilities: Senior Notes to third parties 1 $ 10,958 $ 11,479 $ 10,950 $ 10,945 Senior Notes to affiliates 2 9,986 10,366 9,984 9,802 Incremental Term Loan Facility to affiliates 2 4,000 4,000 4,000 3,976 Senior Reset Notes to affiliates 2 — — 598 640 Guarantee Liabilities We offer a device trade-in program, JUMP!, which provides eligible customers a specified-price trade-in right to upgrade their device. For customers who enroll in JUMP!, we recognize a liability and reduce revenue for the portion of revenue which represents the estimated fair value of the specified-price trade-in right guarantee, incorporating the expected probability and timing of handset upgrade and the estimated fair value of the handset which is returned. Accordingly, our guarantee liabilities were classified as Level 3 within the fair value hierarchy. When customers upgrade their device, the difference between the EIP balance credit to the customer and the fair value of the returned device is recorded against the guarantee liabilities. Guarantee liabilities are included in Other current liabilities in our Consolidated Balance Sheets. The carrying amounts of our guarantee liabilities measured at fair value on a non-recurring basis included in our Consolidated Balance Sheets were $62 million and $73 million as of December 31, 2019, and 2018, respectively. The total estimated remaining gross EIP receivable balances of all enrolled handset upgrade program customers, which are the remaining EIP amounts underlying the JUMP! guarantee, including EIP receivables that have been sold, was $3.0 billion as of December 31, 2019. This is not an indication of our expected loss exposure as it does not consider the expected fair value of the used handset or the probability and timing of the trade-in.

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Note 8 – Debt Debt was as follows: (in millions) December 31, December 31, 5.300% Senior Notes to affiliates due 2021 $ 2,000 $ 2,000 4.000% Senior Notes to affiliates due 2022 1,000 1,000 4.000% Senior Notes due 2022 500 500 Incremental term loan facility to affiliates due 2022 2,000 2,000 6.000% Senior Notes due 2023 1,300 1,300 9.332% Senior Reset Notes to affiliates due 2023 — 600 6.000% Senior Notes due 2024 1,000 1,000 6.500% Senior Notes due 2024 1,000 1,000 6.000% Senior Notes to affiliates due 2024 1,350 1,350 6.000% Senior Notes to affiliates due 2024 650 650 Incremental term loan facility to affiliates due 2024 2,000 2,000 5.125% Senior Notes to affiliates due 2025 1,250 1,250 5.125% Senior Notes due 2025 500 500 6.375% Senior Notes due 2025 1,700 1,700 6.500% Senior Notes due 2026 2,000 2,000 4.500% Senior Notes due 2026 1,000 1,000 4.500% Senior Notes to affiliates due 2026 1,000 1,000 5.375% Senior Notes due 2027 500 500 5.375% Senior Notes to affiliates due 2027 1,250 1,250 4.750% Senior Notes due 2028 1,500 1,500 4.750% Senior Notes to affiliates due 2028 1,500 1,500 Capital leases (1) — 2,015 Unamortized premium on debt to affiliates 43 52 Unamortized discount on Senior Notes to affiliates (53) (64) Financing arrangements for property and equipment 25 — Debt issuance costs and consent fees (46) (56) Total debt 24,969 27,547 Less: Current portion of capital leases — 841 Less: Financing arrangements for property and equipment 25 — Total long-term debt $ 24,944 $ 26,706 Classified on the balance sheet as: Long-term debt $ 10,958 $ 12,124 Long-term debt to affiliates 13,986 14,582 Total long-term debt $ 24,944 $ 26,706 (1) Capital lease liabilities previously included in Short-term debt and Long-term debt were reclassified to Financing lease liabilities in our Consolidated Balance Sheet. See Note 1 – Summary of Significant Accounting Policies for additional details. Debt to Affiliates During the year ended December 31, 2019, we made the following note redemption: (in millions) Principal Amount Write -off of Embedded Derivatives (1) Other (2) Redemption Redemption Price 9.332% Senior Notes due 2023 $ 600 $ 11 $ 28 April 28, 2019 104.6660 % (1) Certain components of the reset features were required to be bifurcated from the DT Senior Reset Notes and separately accounted for as embedded derivative instruments. The write-off of embedded derivatives upon redemption resulted in a gain and is included in Other expense, net in our Consolidated Statements of Comprehensive Income and in Losses on redemption of debt within Net cash provided by operating activities in our Consolidated Statements of Cash Flows. (2) Cash for the premium portion of the redemption price set forth in the indenture governing the DT Senior Reset Notes, plus accrued but unpaid interest on the DT Senior Reset Notes. The redemption premium was included in Other expense, net in our Consolidated Statements of Comprehensive Income and in Cash payments for debt prepayment or debt extinguishment costs in our Consolidated Statements of Cash Flows. Incremental Term Loan Facility In March 2018, we amended the terms of our secured term loan facility (“Incremental Term Loan Facility”) with DT, our majority stockholder. Following this amendment, the applicable margin payable on LIBOR indexed loans is 1.50% under the $2.0 billion Incremental Term Loan Facility maturing on November 9, 2022 and 1.75% under the $2.0 billion Incremental Term Loan Facility maturing on January 31, 2024. The amendment also modified the Incremental Term Loan Facility to update certain covenants and other provisions to make them substantially consistent, subject to certain additional carve outs, with our most recently issued public notes. No issuance fees were incurred related to this debt facility for the years ended December 31, 2019 and 2018. Commitment Letter In connection with the entry into the Business Combination Agreement, T-Mobile USA entered into a commitment letter, dated as of April 29, 2018 (as amended and restated on May 15, 2018 and on September 6, 2019, the “Commitment Letter”), with certain financial institutions named therein that have committed to provide up to $30.0 billion in secured and unsecured debt financing, including a $4.0 billion secured revolving credit facility, a $7.0 billion secured term loan facility, and a $19.0 billion secured bridge loan facility. On September 6, 2019, T-Mobile USA amended and restated the Commitment Letter which (i) reduced the commitments under the secured term loan facility from $7.0 billion to $4.0 billion and (ii) extended the commitments thereunder through May 1, 2020. The funding of the debt facilities provided for in the Commitment Letter is subject to the satisfaction of the conditions set forth therein, including consummation of the Merger. The proceeds of the debt financing provided for in the Commitment Letter will be used to refinance certain existing debt of us, Sprint and our and Sprint’s respective subsidiaries and for post-closing working capital needs of the combined company. In connection with the financing provided for in the Commitment Letter, we expect to incur certain fees payable to the financial institutions, including certain financing fees on the secured term loan commitment. If the Merger closes, we will incur additional fees for the financial institutions structuring and providing the commitments and certain take-out fees associated with the issuance of permanent secured bond debt in lieu of the secured bridge loan. In total, we may incur up to approximately $340 million in fees associated with the Commitment Letter. We began incurring certain Commitment Letter fees on November 1, 2019, which were recognized in Selling, general and administrative expenses in our Consolidated Statements of Comprehensive Income. There were $12 million of fees accrued as of December 31, 2019. Financing Matters Agreement Pursuant to the Financing Matters Agreement, DT agreed, among other things, to consent to the incurrence by T-Mobile USA of secured debt in connection with and after the consummation of the Merger, and to provide a lock up on sales thereby as to certain senior notes of T-Mobile USA held thereby. In addition, T-Mobile USA agreed, among other things, to repay and terminate, upon closing of the Merger, the Incremental Term Loan Facility and the revolving credit facility of T-Mobile USA which are provided by DT, as well as $2.0 billion of T-Mobile USA’s 5.300% Senior Notes due 2021 and $2.0 billion of T-Mobile USA’s 6.000% Senior Notes due 2024. In addition, T-Mobile USA and DT agreed, upon closing of the Merger, to amend the $1.25 billion of T-Mobile USA’s 5.125% Senior Notes due 2025 and $1.25 billion of T-Mobile USA’s 5.375% Senior Notes due 2027 to change the maturity dates thereof to April 15, 2021 and April 15, 2022, respectively (the “2025 and 2027 Amendments”). In connection with receiving the requisite consents, we made upfront payments to DT of $7 million during the second quarter of 2018. These payments were recognized as a reduction to Long-term debt to affiliates in our Consolidated Balance Sheets. In accordance with the consents received from DT, on December 20, 2018, T-Mobile USA, the guarantors and Deutsche Bank Trust Company Americas, as trustee, executed and delivered the 38 th supplemental indenture to the Indenture, pursuant to which, with respect to certain T-Mobile USA Senior Notes held by DT, the Proposed Amendments (as defined below under “Consents on Debt to Third Parties”) and the 2025 and 2027 Amendments will become effective immediately prior to the consummation of the Merger. If the Merger is consummated, we will make additional payments for requisite consents to DT of $13 million. There were no additional payments accrued as of December 31, 2019 and 2018. Consents on Debt to Third Parties On May 18, 2018, under the terms and conditions described in the Consent Solicitation Statement, we obtained consents necessary to effect certain amendments to our Senior Notes to third parties in connection with the Business Combination Agreement. Pursuant to the Consent Solicitation Statement, third-party note holders agreed, among other things, to consent to increasing the amount of Secured Indebtedness under Credit Facilities that can be incurred from the greater of $9.0 billion and 150% of Consolidated Cash Flow to the greater of $9.0 billion and an amount that would not cause the Secured Debt to Cash Flow Ratio (calculated net of cash and cash equivalents) to exceed 2.00x (the “Ratio Secured Debt Proposed Amendments”) and in each case as such capitalized term is defined in the Indenture. In connection with receiving the requisite consents for the Ratio Secured Debt Proposed Amendments, we made upfront payments to third-party note holders of $17 million during the second quarter of 2018. These payments were recognized as a reduction to Long-term debt in our Consolidated Balance Sheets. These upfront payments increased the effective interest rate of the related debt. In addition, note holders agreed, among other things, to allow certain entities related to Sprint’s existing spectrum securitization notes program (“Existing Sprint Spectrum Program”) to be non-guarantor Restricted Subsidiaries, provided that the principal amount of the spectrum notes issued and outstanding under the Existing Sprint Spectrum Program does not exceed $7.0 billion and that the principal amount of such spectrum notes reduces the amount available under the Credit Facilities ratio basket, and to revise the definition of GAAP to mean generally accepted accounting principles in effect from time to time, unless the Company elects to “freeze” GAAP as of any date, and to exclude the effect of the changes in the accounting treatment of lease obligations (the “Existing Sprint Spectrum and GAAP Proposed Amendments,” and together with the Ratio Secured Debt Proposed Amendments, the “Proposed Amendments”). In connection with receiving the requisite consents for the Existing Sprint Spectrum and GAAP Proposed Amendments, we made upfront payments to third-party note holders of $14 million during the second quarter of 2018. These payments were recognized as a reduction to Long-term debt in our Consolidated Balance Sheets. These upfront payments increased the effective interest rate of the related debt. In connection with obtaining the requisite consents, on May 20, 2018, T-Mobile USA, the guarantors and Deutsche Bank Trust Company Americas, as trustee, executed and delivered the 37 th supplemental indenture to the Indenture, pursuant to which, with respect to each of the Notes, the Proposed Amendments will become effective immediately prior to the consummation of the Merger. We paid third-party bank fees associated with obtaining the requisite consents related to the Proposed Amendments of $6 million during the second quarter of 2018, which we recognized as Selling, general and administrative expenses in our Consolidated Statements of Comprehensive Income. If the Merger is consummated, we will make additional payments to third-party note holders for requisite consents related to the Ratio Secured Debt Proposed Amendments of up to $54 million and additional payments to third-party note holders for requisite consents related to the Existing Sprint Spectrum and GAAP Proposed Amendments of up to $41 million. There were no payments accrued as of December 31, 2019. Financing Arrangements We maintain a financing arrangement with Deutsche Bank AG, which allows for up to $108 million in borrowings. Under the financing arrangement, we can effectively extend payment terms for invoices payable to certain vendors. The interest rate on the financing arrangement is determined based on LIBOR plus a specified margin per the arrangement. Obligations under the financing arrangement are included in Short-term debt in our Consolidated Balance Sheets. As of December 31, 2019 and 2018, there were no outstanding balances. We maintain vendor financing arrangements with our primary network equipment suppliers. Under the respective agreements, we can obtain extended financing terms. During the year ended December 31, 2019, we utilized $800 million and repaid $775 million under the vendor financing arrangements. Invoices subject to extended payment terms have various due dates through the first quarter of 2020. Payments on vendor financing agreements are included in Repayments of short-term debt for purchases of inventory, property and equipment, net, in our Consolidated Statements of Cash Flows. As of December 31, 2019, there was $25 million in outstanding borrowings under the vendor financing agreements which were included in Short-term debt in our Consolidated Balance Sheets. As of December 31, 2018, there was no outstanding balance. Revolving Credit Facility We maintain a $2.5 billion revolving credit facility with DT which is comprised of a $1.0 billion unsecured revolving credit agreement and a $1.5 billion secured revolving credit agreement. In December 2019, we amended the terms of the revolving credit facility with DT to extend the maturity date to December 29, 2022. The proceeds and borrowings from the revolving credit facility are presented in Proceeds from borrowing on revolving credit facility and Repayments of revolving credit facility within Net cash used in financing activities in our Consolidated Statements of Cash Flows. As of December 31, 2019 and 2018, there were no outstanding borrowings under the revolving credit facility. Standby Letters of Credit For the purposes of securing our obligations to provide handset insurance services, we maintain an agreement for standby letters of credit with JP Morgan Chase Bank, N.A. (“JP Morgan Chase”). For purposes of securing our general purpose obligations, we maintain a letter of credit reimbursement agreement with Deutsche Bank. The following table summarizes the outstanding standby letters of credit under each agreement: (in millions) December 31, 2019 December 31, 2018 JP Morgan Chase $ 20 $ 20 Deutsche Bank 93 66 Total outstanding balance $ 113 $ 86

Tower Obligations

Tower Obligations	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Tower Obligations	Note 9 – Tower Obligations In 2012, we conveyed to CCI the exclusive right to manage and operate approximately 7,100 T-Mobile-owned wireless communications tower sites in exchange for net proceeds of $2.5 billion (the “2012 Tower Transaction”). Rights to approximately 6,200 of the tower sites were transferred to CCI via a master prepaid lease with site lease terms ranging from 23 to 37 years (“CCI Lease Sites”), while the remaining tower sites were sold to CCI (“CCI Sales Sites”). CCI has fixed-price purchase options for the CCI Lease Sites totaling approximately $2.0 billion, exercisable at the end of the lease term. We lease back space at certain tower sites for an initial term of ten years, followed by optional renewals at customary terms. In 2015, we conveyed to PTI the exclusive right to manage and operate certain T-Mobile-owned wireless communications tower sites (“PTI Sales Sites”) in exchange for net proceeds of approximately $140 million (the “2015 Tower Transaction”). Rights to approximately 150 of the tower sites remain operated by PTI under a management agreement. We lease back space at certain tower sites for an initial term of ten years, followed by optional renewals at customary terms. Assets and liabilities associated with the operation of the tower sites were transferred to special purpose entities (“SPEs”). Assets included ground lease agreements or deeds for the land on which the towers are situated, the towers themselves and existing subleasing agreements with other mobile network operator tenants, who lease space at the tower sites. Liabilities included the obligation to pay ground lease rentals, property taxes and other executory costs. Upon closing of the 2012 Tower Transaction, CCI acquired all of the equity interests in the SPE containing CCI Sales Sites and an option to acquire the CCI Lease Sites at the end of their respective lease terms and entered into a master lease agreement under which we agreed to lease back space at certain of the tower sites. Upon closing of the 2015 Tower Transaction, PTI acquired all of the equity interests in the SPEs containing PTI Sales Sites and entered into a master lease agreement under which we agreed to lease back space at certain of the tower sites. We determined the SPEs containing the CCI Lease Sites (“Lease Site SPEs”) are VIEs as our equity investment lacks the power to direct the activities that most significantly impact the economic performance of the VIEs. These activities include managing tenants and underlying ground leases, performing repair and maintenance on the towers, the obligation to absorb expected losses and the right to receive the expected future residual returns from the purchase option to acquire the CCI Lease Sites. As we determined that we are not the primary beneficiary and do not have a controlling financial interest in the Lease Site SPEs, the balances and operating results of the Lease Site SPEs are not included in our Consolidated Financial Statements. Due to our continuing involvement with the tower sites, we previously determined that we were precluded from applying sale-leaseback accounting. We recorded long-term financial obligations in the amount of the net proceeds received and recognized interest on the tower obligations at a rate of approximately 8% for the 2012 Tower Transaction and 5% for the 2015 Tower Transaction using the effective interest method. The tower obligations are increased by interest expense and amortized through contractual leaseback payments made by us to CCI or PTI and through net cash flows generated and retained by CCI or PTI from operation of the tower sites. The principal payments on the tower obligations are included in Other, net within Net cash used in financing activities in our Consolidated Statements of Cash Flows . Our historical tower site asset costs are reported in Property and equipment, net in our Consolidated Balance Sheets and are depreciated. Upon adoption of the new leasing standard we were required to reassess the previously failed sale-leasebacks and determine whether the transfer of the assets to the tower operator under the arrangement met the transfer of control criteria in the revenue standard and whether a sale should be recognized. We concluded that a sale has not occurred for the CCI Lease Sites and these sites continue to be accounted for as a failed sale-leaseback. We concluded that a sale had occurred for the CCI Sales Sites and the PTI Sales Sites and therefore we derecognized our existing long-term financial obligation and the tower-related property and equipment associated with these sites as part of the cumulative effect adjustment on January 1, 2019. See Note 1 - Summary of Significant Accounting Policies for further information. The following table summarizes the balances of the failed sale-leasebacks in the Consolidated Balance Sheets: (in millions) December 31, 2019 December 31, 2018 Property and equipment, net $ 198 $ 329 Tower obligations 2,236 2,557 Future minimum payments related to the tower obligations are approximately $160 million for the year ending December 31, 2020, $321 million in total for the years ending December 31, 2021 and 2022, $320 million in total for years ending December 31, 2023 and 2024, and $467 million in total for years thereafter. We are contingently liable for future ground lease payments through the remaining term of the CCI Lease Sites. These contingent obligations are not included in Operating lease liabilities as any amount due is contractually owed by CCI based on the subleasing arrangement.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Note 10 – Revenue from Contracts with Customers Disaggregation of Revenue We provide wireless communications services to three primary categories of customers: • Branded postpaid customers generally include customers who are qualified to pay after receiving wireless communications services utilizing phones, wearables, DIGITS, or other connected devices which includes tablets and SyncUP DRIVE™; • Branded prepaid customers generally include customers who pay for wireless communications services in advance. Our branded prepaid customers include customers of T-Mobile and Metro by T-Mobile; and • Wholesale customers include Machine-to-Machine (“M2M”) and Mobile Virtual Network Operator (“MVNO”) customers that operate on our network but are managed by wholesale partners. Branded postpaid service revenues, including branded postpaid phone revenues and branded postpaid other revenues, were as follows: Year Ended December 31, (in millions) 2019 2018 2017 Branded postpaid service revenues Branded postpaid phone revenues $ 21,329 $ 19,745 $ 18,371 Branded postpaid other revenues 1,344 1,117 1,077 Total branded postpaid service revenues $ 22,673 $ 20,862 $ 19,448 We operate as a single operating segment. The balances presented within each revenue line item in our Consolidated Statements of Comprehensive Income represent categories of revenue from contracts with customers disaggregated by type of product and service. Service revenues also include revenues earned for providing value added services to customers, such as handset insurance services. Revenue generated from the lease of mobile communication devices is included within Equipment revenues in our Consolidated Statements of Comprehensive Income. Equipment revenues from the lease of mobile communication devices were as follows: Year Ended December 31, (in millions) 2019 2018 2017 Equipment revenues from the lease of mobile communication devices $ 599 $ 692 $ 877 Contract Balances The opening and closing balances of our contract asset and contract liability balances from contracts with customers as of December 31, 2018 and December 31, 2019, were as follows: (in millions) Contract Assets Contract Liabilities Balance as of December 31, 2018 $ 51 $ 645 Balance as of December 31, 2019 63 560 Change $ 12 $ (85) Contract assets primarily represent revenue recognized for equipment sales with promotional bill credits offered to customers that are paid over time and are contingent on the customer maintaining a service contract. The change in the contract asset balance includes customer activity related to new promotions, offset by billings on existing contracts and impairment which is recognized as bad debt expense. The current portion of our Contract Assets of approximately $50 million and $51 million as of December 31, 2019 and 2018, respectively, was included in Other current assets in our Consolidated Balance Sheets. Contract liabilities are recorded when fees are collected, or we have an unconditional right to consideration (a receivable) in advance of delivery of goods or services. The change in contract liabilities is primarily related to the migration of customers to unlimited rate plans. Contract liabilities are included in Deferred revenue in our Consolidated Balance Sheets. Revenues for the years ended December 31, 2019 and 2018, include the following: Year Ended December 31, (in millions) 2019 2018 Amounts included in the beginning of year contract liability balance $ 643 $ 710 Remaining Performance Obligations As of December 31, 2019, the aggregate amount of transaction price allocated to remaining service performance obligations for branded postpaid contracts with promotional bill credits that result in an extended service contract is $237 million. We expect to recognize this revenue as service is provided over the extended contract term in the next 24 months. Certain of our wholesale, roaming and other service contracts include variable consideration based on usage. This variable consideration has been excluded from the disclosure of remaining performance obligations. As of December 31, 2019, the aggregate amount of the contractual minimum consideration for wholesale, roaming and other service contracts is $1.3 billion, $894 million and $791 million for 2020, 2021 and 2022 and beyond, respectively. These contracts have a remaining duration ranging from less than one year to ten years. Information about remaining performance obligations that are part of a contract that has an original expected duration of one year or less have been excluded from the above, which primarily consists of monthly service contracts. Contract Costs The total balance of deferred incremental costs to obtain contracts was $906 million and $644 million as of December 31, 2019 and 2018, respectively. Deferred contract costs incurred to obtain postpaid service contracts are amortized over a period of 24 months. The amortization period is monitored to reflect any significant change in assumptions. Amortization of deferred contract costs is included in Selling, general and administrative expenses in our Consolidated Statements of Comprehensive Income and was $604 million and $267 million for the years ended December 31, 2019 and 2018, respectively. The deferred contract cost asset is assessed for impairment on a periodic basis. There were no impairment losses recognized on deferred contract cost assets for the years ended December 31, 2019 and 2018.

Employee Compensation and Benef

Employee Compensation and Benefit Plans	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Employee Compensation and Benefit Plans	Note 11 – Employee Compensation and Benefit Plans Under our 2013 Omnibus Incentive Plan (the "Incentive Plan"), we are authorized to issue up to 82 million shares of our common stock. Under the Incentive Plan, we can grant stock options, stock appreciation rights, restricted stock, restricted stock units ("RSUs"), and performance awards to eligible employees, consultants, advisors and non-employee directors. As of December 31, 2019, there were approximately 19 million shares of common stock available for future grants under the Incentive Plan. We grant RSUs to eligible employees, key executives and certain non-employee directors and performance-based restricted stock units (“PRSUs”) to eligible key executives. RSUs entitle the grantee to receive shares of our common stock upon vesting (with vesting generally occurring annually over a three Stock-based compensation expense and related income tax benefits were as follows: (in millions, except shares, per share and contractual life amounts) December 31, 2019 December 31, 2018 December 31, 2017 Stock-based compensation expense $ 495 $ 424 $ 306 Income tax benefit related to stock-based compensation $ 92 $ 81 $ 73 Weighted average fair value per stock award granted $ 73.25 $ 61.52 $ 60.21 Unrecognized compensation expense $ 515 $ 547 $ 445 Weighted average period to be recognized (years) 1.6 1.8 1.9 Fair value of stock awards vested $ 512 $ 471 $ 503 Stock Awards Time-Based Restricted Stock Units and Restricted Stock Awards (in millions, except shares, per share and contractual life amounts) Number of Units or Awards Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Nonvested, December 31, 2018 11,010,635 $ 57.66 1.0 $ 700 Granted 6,099,719 73.13 Vested (5,862,128) 55.52 Forfeited (745,015) 65.87 Nonvested, December 31, 2019 10,503,211 67.31 0.9 824 Performance-Based Restricted Stock Units and Restricted Stock Awards (in millions, except shares, per share and contractual life amounts) Number of Units or Awards Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Nonvested, December 31, 2018 3,851,554 $ 64.03 1.6 $ 245 Granted 1,046,792 73.98 Vested (1,006,404) 52.47 Forfeited (88,403) 62.02 Nonvested, December 31, 2019 3,803,539 69.78 1.0 300 PRSUs included in the table above are shown at target. Share payout can range from 0% to 200% based on different performance outcomes. Payment of the underlying shares in connection with the vesting of stock awards generally triggers a tax obligation for the employee, which is required to be remitted to the relevant tax authorities. We have agreed to withhold shares of common stock otherwise issuable under the award to cover certain of these tax obligations, with the net shares issued to the employee accounted for as outstanding common stock. We withheld 2,094,555 and 2,321,827 shares of common stock to cover tax obligations associated with the payment of shares upon vesting of stock awards and remitted cash of $156 million and $146 million to the appropriate tax authorities for the years ended December 31, 2019 and 2018, respectively. Employee Stock Purchase Plan Our ESPP allows eligible employees to contribute up to 15% of their eligible earnings toward the semi-annual purchase of our shares of common stock at a discounted price, subject to an annual maximum dollar amount. Employees can purchase stock at a 15% discount applied to the closing stock price on the first or last day of the six Our ESPP provides for an annual increase in the aggregate number of shares of our common stock reserved for sale and authorized for issuance thereunder as of the first day of each fiscal year (beginning with fiscal year 2016) equal to the lesser of (i) 5,000,000 shares of our common stock, and (ii) the number of shares of Common Stock determined by the Compensation Committee of the Board of Directors of the Company (the “Compensation Committee”). For fiscal years 2016 through 2019, the Compensation Committee determined that no such increase in shares of our common stock was necessary. However, an additional 5,000,000 shares of our common stock were automatically added to the ESPP share reserve as of January 1, 2020. Stock Options Stock options outstanding relate to the Metro Communications, Inc. 2010 Equity Incentive Compensation Plan, the Amended and Restated Metro Communications, Inc. 2004 Equity Incentive Compensation Plan, and the Layer3 TV, Inc. 2013 Stock Plan (collectively, the “Stock Option Plans”). No new awards have been or may be granted under the Stock Option Plans. The following activity occurred under the Stock Option Plans: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Outstanding at December 31, 2018 284,811 $ 14.58 3.8 Exercised (85,083) 15.94 Expired/canceled (4,786) 22.75 Outstanding at December 31, 2019 194,942 13.80 2.9 Exercisable at December 31, 2019 180,966 13.48 2.6 Stock options exercised under the Stock Option Plans generated proceeds of approximately $1 million and $3 million for the years ended December 31, 2019 and 2018, respectively. Employee Retirement Savings Plan We sponsor a retirement savings plan for the majority of our employees under Section 401(k) of the Internal Revenue Code and similar plans. The plans allow employees to contribute a portion of their pretax and post-tax income in accordance with specified guidelines. The plans provide that we match a percentage of employee contributions up to certain limits. Employer matching contributions were $119 million, $102 million and $87 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Repurchases of Common Stock

Repurchases of Common Stock	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Repurchases of Common Stock	Note 12 – Repurchases of Common Stock 2017 Stock Repurchase Program On December 6, 2017, our Board of Directors authorized a stock repurchase program for up to $1.5 billion of our common stock through December 31, 2018 (the “2017 Stock Repurchase Program”). Repurchased shares are retired. The 2017 Stock Repurchase Program completed on April 29, 2018. The following table summarizes information regarding repurchases of our common stock under the 2017 Stock Repurchase Program: (In millions, except shares and per share price) Year ended December 31, Number of Shares Repurchased Average Price Paid Per Share Total Purchase Price 2018 16,738,758 $ 62.96 $ 1,054 2017 7,010,889 63.34 444 23,749,647 63.07 $ 1,498 2018 Stock Repurchase Program On April 27, 2018, our Board of Directors authorized an increase in the total stock repurchase program to $9.0 billion, consisting of the $1.5 billion in repurchases previously completed and for up to an additional $7.5 billion of repurchases of our common stock through the year ending December 31, 2020 (the "2018 Stock Repurchase Program"). The additional $7.5 billion repurchase authorization is contingent upon the termination of the Business Combination Agreement and the abandonment of the transactions contemplated under the Business Combination Agreement. There were no repurchases of our common stock under the 2018 Stock Repurchase Program in 2019 or 2018. Under the 2018 Stock Repurchase Program, repurchases can be made from time to time using a variety of methods, which may include open market purchases, privately negotiated transactions or otherwise, all in accordance with the rules of the SEC and other applicable legal requirements. The specific timing, price and size of purchases will depend on prevailing stock prices, general economic and market conditions, and other considerations. The 2018 Stock Repurchase Program does not obligate us to acquire any particular amount of common stock, and the repurchase program may be suspended or discontinued at any time at our discretion. Repurchased shares are retired. Stock Purchases by Affiliate In the first quarter of 2018, DT, our majority stockholder and an affiliated purchaser, purchased 3.3 million additional shares of our common stock at an aggregate market value of $200 million in the public market or from other parties, in accordance with the rules of the SEC and other applicable legal requirements. There were no purchases in the remainder of 2018 and in 2019. We did not receive proceeds from these purchases.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 13 – Income Taxes Our sources of Income before income taxes were as follows: Year Ended December 31, (in millions) 2019 2018 2017 U.S. $ 4,557 $ 3,686 $ 3,274 Puerto Rico 46 231 (113) Income before income taxes $ 4,603 $ 3,917 $ 3,161 Income tax (expense) benefit is summarized as follows: Year Ended December 31, (in millions) 2019 2018 2017 Current tax benefit (expense) Federal $ 24 $ 39 $ — State (70) (63) (28) Puerto Rico 2 (25) (1) Total current tax expense (44) (49) (29) Deferred tax benefit (expense) Federal (954) (750) 1,182 State (125) (160) 173 Puerto Rico (12) (70) 49 Total deferred tax (expense) benefit (1,091) (980) 1,404 Total income tax (expense) benefit $ (1,135) $ (1,029) $ 1,375 The reconciliation between the U.S. federal statutory income tax rate and our effective income tax rate is as follows: Year Ended December 31, 2019 2018 2017 Federal statutory income tax rate 21.0 % 21.0 % 35.0 % Effect of law and rate changes 0.4 1.9 (68.9) Change in valuation allowance (1.8) (1.6) (11.4) State taxes, net of federal benefit 5.1 4.8 4.8 Equity-based compensation (0.6) (0.6) (2.4) Puerto Rico taxes, net of federal benefit 0.3 2.4 (1.5) Permanent differences 1.2 1.3 0.5 Federal tax credits, net of reserves (0.8) (2.9) 0.3 Other, net (0.1) — 0.1 Effective income tax rate 24.7 % 26.3 % (43.5) % Significant components of deferred income tax assets and liabilities, tax effected, are as follows: (in millions) December 31, December 31, Deferred tax assets Loss carryforwards $ 823 $ 1,526 Deferred rents — 784 Lease liability 3,403 — Reserves and accruals 659 668 Federal and state tax credits 331 340 Other 903 620 Deferred tax assets, gross 6,119 3,938 Valuation allowance (129) (210) Deferred tax assets, net 5,990 3,728 Deferred tax liabilities Spectrum licenses 5,902 5,494 Property and equipment 2,506 2,434 Lease right-of-use assets 2,881 — Other intangible assets 19 40 Other 289 232 Total deferred tax liabilities 11,597 8,200 Net deferred tax liabilities $ 5,607 $ 4,472 Classified on the balance sheet as: Deferred tax liabilities $ 5,607 $ 4,472 As of December 31, 2019, we have tax effected net operating loss (“NOL”) carryforwards of $470 million for federal income tax purposes and $710 million for state income tax purposes, expiring through 2039. Federal NOLs and certain state NOLs generated in and after 2018 do not expire. As of December 31, 2019, our tax effected federal and state NOL carryforwards for financial reporting purposes were approximately $138 million and $282 million, respectively, less than our NOL carryforwards for federal and state income tax purposes, due to unrecognized tax benefits of the same amount. The unrecognized tax benefit amounts exclude indirect tax effects of $63 million in other jurisdictions. As of December 31, 2019, we have available Alternative Minimum Tax (“AMT”) credit carryforwards of $23 million. The AMT credits will be fully recovered by 2021. We also have research and development and foreign tax credit carryforwards with a combined value of $347 million for federal income tax purposes, which begin to expire in 2020. As of December 31, 2019, 2018 and 2017, our valuation allowance was $129 million, $210 million and $273 million, respectively. The change from December 31, 2018 to December 31, 2019 primarily related to a reduction in the valuation allowance against deferred tax assets in certain state jurisdictions resulting from legal entity reorganizations. The change from December 31, 2017 to December 31, 2018 primarily related to a reduction in the valuation allowance against deferred tax assets in certain state jurisdictions from a change in tax status of certain subsidiaries. We will continue to monitor positive and negative evidence related to the utilization of the remaining deferred tax assets for which a valuation allowance continues to be provided. It is possible that our valuation allowance may change within the next twelve months. We file income tax returns in the U.S. federal jurisdiction, various state jurisdictions and in Puerto Rico. We are currently under examination by various states. Management does not believe the resolution of any of the audits will result in a material change to our financial condition, results of operations or cash flows. The IRS has concluded its audits of our federal tax returns through the 2013 tax year; however, NOL and other carryforwards for certain audited periods remain open for examination. We are generally closed to U.S. federal, state and Puerto Rico examination for years prior to 2000. A reconciliation of the beginning and ending amount of unrecognized tax benefits were as follows: Year Ended December 31, (in millions) 2019 2018 2017 Unrecognized tax benefits, beginning of year $ 462 $ 412 $ 410 Gross (decreases) increases to tax positions in prior periods (7) 6 (10) Gross increases due to current period business acquisitions — 10 — Gross increases to current period tax positions 59 34 12 Unrecognized tax benefits, end of year $ 514 $ 462 $ 412 As of December 31, 2019 and 2018, we had $367 million and $315 million, respectively, in unrecognized tax benefits that, if recognized, would affect our annual effective tax rate. Penalties and interest on income tax assessments are included in Selling, general and administrative expenses and Interest expense, respectively, in our Consolidated Statements of Comprehensive Income. The accrued interest and penalties associated with unrecognized tax benefits are insignificant.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Note 14 – Earnings Per Share The computation of basic and diluted earnings per share was as follows: Year Ended December 31, (in millions, except shares and per share amounts) 2019 2018 2017 Net income $ 3,468 $ 2,888 $ 4,536 Less: Dividends on mandatory convertible preferred stock — — (55) Net income attributable to common stockholders - basic 3,468 2,888 4,481 Add: Dividends related to mandatory convertible preferred stock — — 55 Net income attributable to common stockholders $ 3,468 $ 2,888 $ 4,536 Weighted average shares outstanding - basic 854,143,751 849,744,152 831,850,073 Effect of dilutive securities: Outstanding stock options and unvested stock awards 9,289,760 8,546,022 9,200,873 Mandatory convertible preferred stock — — 30,736,504 Weighted average shares outstanding - diluted 863,433,511 858,290,174 871,787,450 Earnings per share - basic $ 4.06 $ 3.40 $ 5.39 Earnings per share - diluted $ 4.02 $ 3.36 $ 5.20 Potentially dilutive securities: Outstanding stock options and unvested stock awards 16,359 148,422 33,980 As of December 31, 2019, we had authorized 100 million shares of preferred stock, with a par value of $0.00001 per share. There was no preferred stock outstanding as of December 31, 2019 and 2018. Potentially dilutive securities were not included in the computation of diluted earnings per share if to do so would have been anti-dilutive.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Note 15 - Leases Leases (Topic 842) Disclosures Lessee We are lessee for non-cancelable operating and financing leases for cell sites, switch sites, retail stores and office facilities with contractual terms that generally extend through 2029. The majority of cell site leases have an initial non-cancelable term of five five two The components of lease expense were as follows: (in millions) Year Ended December 31, 2019 Operating lease expense $ 2,558 Financing lease expense: Amortization of right-of-use assets 523 Interest on lease liabilities 82 Total financing lease expense 605 Variable lease expense 243 Total lease expense $ 3,406 Information relating to the lease term and discount rate is as follows: December 31, 2019 Weighted Average Remaining Lease Term (Years) Operating leases 6 Financing leases 3 Weighted Average Discount Rate Operating leases 4.8 % Financing leases 4.0 % Maturities of lease liabilities as of December 31, 2019, were as follows: (in millions) Operating Leases Finance Leases Twelve Months Ending December 31, 2020 $ 2,754 $ 1,013 2021 2,583 733 2022 2,311 414 2023 1,908 101 2024 1,615 71 Thereafter 3,797 115 Total lease payments 14,968 2,447 Less imputed interest 2,142 144 Total $ 12,826 $ 2,303 Interest payments for financing leases for the year ended December 31, 2019, were $82 million. As of December 31, 2019, we have additional operating leases for cell sites and commercial properties that have not yet commenced with future lease payments of approximately $341 million. As of December 31, 2019, we were contingently liable for future ground lease payments related to the tower obligations. These contingent obligations are not included in the above table as the amounts owed are contractually owed by CCI based on the subleasing arrangement. See Note 9 - Tower Obligations for further information. Lessor JUMP! On Demand allows customers to lease a device (handset or tablet) over a period of 18 months and upgrade it for a new device up to one time per month. Upon device upgrade or at lease end, customers must return or purchase their device. The purchase price at the expiration of the lease is established at lease commencement and reflects the estimated residual value of the device, which reflects the estimated fair value of the underlying asset at the end of the lease term. The JUMP! On Demand leases do not contain any residual value guarantees or variable lease payments, and there are no restrictions or covenants imposed by these leases. Leased wireless devices are included in Property and equipment, net in our Consolidated Balance Sheets. The components of leased wireless devices under our JUMP! On Demand program were as follows: (in millions) December 31, 2019 December 31, 2018 Leased wireless devices, gross $ 1,139 $ 1,159 Accumulated depreciation (407) (622) Leased wireless devices, net $ 732 $ 537 For equipment revenues from the lease of mobile communication devices, see Note 10 - Revenue from Contracts with Customers . Future minimum payments expected to be received over the lease term related to the leased wireless devices, which exclude optional residual buy-out amounts at the end of the lease term, are summarized below: (in millions) Total Twelve Months Ending December 31, 2020 $ 417 2021 99 Total $ 516 Leases (Topic 840) Disclosures On January 1, 2019, we adopted the new lease standard using a modified-retrospective approach by recognizing and measuring leases at the adoption date with a cumulative effect of initially applying the guidance recognized at the date of initial application and did not restate the prior periods presented in our Consolidated Financial Statements. As such, prior periods presented in our Consolidated Financial Statements continue to be in accordance with the former lease standard, Topic 840 Leases. See Note 1 - Summary of Significant Accounting Policies for further information. Operating Leases Under the previous lease standard, we had non-cancelable operating leases for cell sites, switch sites, retail stores and office facilities. As of December 31, 2018, these leases had contractual terms expiring through 2028, with the majority of cell site leases having an initial non-cancelable term of five Our commitments under leases existing as of December 31, 2018 were approximately $2.7 billion for the year ending December 31, 2019, $4.7 billion in total for the years ending December 31, 2020 and 2021, $3.3 billion in total for the years ending December 31, 2022 and 2023 and $3.8 billion in total for years thereafter. Total rent expense under operating leases, including dedicated transportation lines, was $3.0 billion for the year ended December 31, 2018, and was classified as Cost of services and Selling, general and administrative expense in our Consolidated Statements of Comprehensive Income. Lessor As of December 31, 2018, the future minimum payments expected to be received over the lease term related to the leased wireless devices, which exclude optional residual buy-out amounts at the end of the lease term, are summarized below: (in millions) Total Year Ended December 31, 2019 $ 419 2020 59 Total $ 478 Capital Leases Within property and equipment, wireless communications systems include capital lease agreements for network equipment with varying expiration terms through 2033. Capital lease assets and accumulated amortization were $3.1 billion and $867 million as of December 31, 2018. As of December 31, 2018, the future minimum payments required under capital leases, including interest and maintenance, over their remaining terms are summarized below: (in millions) Future Minimum Payments Year Ended December 31, 2019 $ 909 2020 631 2021 389 2022 102 2023 66 Thereafter 106 Total $ 2,203 Included in Total Interest $ 143 Maintenance 45
Leases	Note 15 - Leases Leases (Topic 842) Disclosures Lessee We are lessee for non-cancelable operating and financing leases for cell sites, switch sites, retail stores and office facilities with contractual terms that generally extend through 2029. The majority of cell site leases have an initial non-cancelable term of five five two The components of lease expense were as follows: (in millions) Year Ended December 31, 2019 Operating lease expense $ 2,558 Financing lease expense: Amortization of right-of-use assets 523 Interest on lease liabilities 82 Total financing lease expense 605 Variable lease expense 243 Total lease expense $ 3,406 Information relating to the lease term and discount rate is as follows: December 31, 2019 Weighted Average Remaining Lease Term (Years) Operating leases 6 Financing leases 3 Weighted Average Discount Rate Operating leases 4.8 % Financing leases 4.0 % Maturities of lease liabilities as of December 31, 2019, were as follows: (in millions) Operating Leases Finance Leases Twelve Months Ending December 31, 2020 $ 2,754 $ 1,013 2021 2,583 733 2022 2,311 414 2023 1,908 101 2024 1,615 71 Thereafter 3,797 115 Total lease payments 14,968 2,447 Less imputed interest 2,142 144 Total $ 12,826 $ 2,303 Interest payments for financing leases for the year ended December 31, 2019, were $82 million. As of December 31, 2019, we have additional operating leases for cell sites and commercial properties that have not yet commenced with future lease payments of approximately $341 million. As of December 31, 2019, we were contingently liable for future ground lease payments related to the tower obligations. These contingent obligations are not included in the above table as the amounts owed are contractually owed by CCI based on the subleasing arrangement. See Note 9 - Tower Obligations for further information. Lessor JUMP! On Demand allows customers to lease a device (handset or tablet) over a period of 18 months and upgrade it for a new device up to one time per month. Upon device upgrade or at lease end, customers must return or purchase their device. The purchase price at the expiration of the lease is established at lease commencement and reflects the estimated residual value of the device, which reflects the estimated fair value of the underlying asset at the end of the lease term. The JUMP! On Demand leases do not contain any residual value guarantees or variable lease payments, and there are no restrictions or covenants imposed by these leases. Leased wireless devices are included in Property and equipment, net in our Consolidated Balance Sheets. The components of leased wireless devices under our JUMP! On Demand program were as follows: (in millions) December 31, 2019 December 31, 2018 Leased wireless devices, gross $ 1,139 $ 1,159 Accumulated depreciation (407) (622) Leased wireless devices, net $ 732 $ 537 For equipment revenues from the lease of mobile communication devices, see Note 10 - Revenue from Contracts with Customers . Future minimum payments expected to be received over the lease term related to the leased wireless devices, which exclude optional residual buy-out amounts at the end of the lease term, are summarized below: (in millions) Total Twelve Months Ending December 31, 2020 $ 417 2021 99 Total $ 516 Leases (Topic 840) Disclosures On January 1, 2019, we adopted the new lease standard using a modified-retrospective approach by recognizing and measuring leases at the adoption date with a cumulative effect of initially applying the guidance recognized at the date of initial application and did not restate the prior periods presented in our Consolidated Financial Statements. As such, prior periods presented in our Consolidated Financial Statements continue to be in accordance with the former lease standard, Topic 840 Leases. See Note 1 - Summary of Significant Accounting Policies for further information. Operating Leases Under the previous lease standard, we had non-cancelable operating leases for cell sites, switch sites, retail stores and office facilities. As of December 31, 2018, these leases had contractual terms expiring through 2028, with the majority of cell site leases having an initial non-cancelable term of five Our commitments under leases existing as of December 31, 2018 were approximately $2.7 billion for the year ending December 31, 2019, $4.7 billion in total for the years ending December 31, 2020 and 2021, $3.3 billion in total for the years ending December 31, 2022 and 2023 and $3.8 billion in total for years thereafter. Total rent expense under operating leases, including dedicated transportation lines, was $3.0 billion for the year ended December 31, 2018, and was classified as Cost of services and Selling, general and administrative expense in our Consolidated Statements of Comprehensive Income. Lessor As of December 31, 2018, the future minimum payments expected to be received over the lease term related to the leased wireless devices, which exclude optional residual buy-out amounts at the end of the lease term, are summarized below: (in millions) Total Year Ended December 31, 2019 $ 419 2020 59 Total $ 478 Capital Leases Within property and equipment, wireless communications systems include capital lease agreements for network equipment with varying expiration terms through 2033. Capital lease assets and accumulated amortization were $3.1 billion and $867 million as of December 31, 2018. As of December 31, 2018, the future minimum payments required under capital leases, including interest and maintenance, over their remaining terms are summarized below: (in millions) Future Minimum Payments Year Ended December 31, 2019 $ 909 2020 631 2021 389 2022 102 2023 66 Thereafter 106 Total $ 2,203 Included in Total Interest $ 143 Maintenance 45

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 16 – Commitments and Contingencies Purchase Commitments We have commitments for non-dedicated transportation lines with varying expiration terms that generally extend through 2035. In addition, we have commitments to purchase and lease spectrum licenses, wireless devices, network services, equipment, software, marketing sponsorship agreements and other items in the ordinary course of business, with various terms through 2043. These amounts are not reflective of our entire anticipated purchases under the related agreements but are determined based on the non-cancelable quantities or termination amounts to which we are contractually obligated. Our purchase commitments are approximately $3.6 billion for the year ending December 31, 2020, $3.3 billion in total for the years ending December 31, 2021 and 2022, $1.6 billion in total for the years ending December 31, 2023 and 2024 and $1.4 billion in total for the years thereafter. In 2018, we signed a reciprocal long-term spectrum lease with Sprint. The lease includes an offsetting amount to be received from Sprint for the lease of our spectrum. Lease payments began in the fourth quarter of 2018. The minimum commitment under this lease as of December 31, 2019, is $481 million and is included in the purchase obligations above. The reciprocal long-term lease is a distinct transaction from the Merger. Under the previous lease standard certain of our network backhaul arrangements were accounted for as operating leases. Obligations under these agreements were included within our operating lease commitments as of December 31, 2018. These agreements no longer qualify as leases under the new lease standard. Our commitments under these agreements as of December 31, 2019, were approximately $164 million for the year ending December 31, 2020, $267 million in total for the years ended December 31, 2021 and 2022, $171 million in total for the years ended December 31, 2023 and 2024, and $196 million in total for years thereafter. The commitments under these agreements are included in the purchase commitments above. Interest rate lock derivatives We have entered into interest rate lock derivatives with notional amounts of $9.6 billion. These interest rate lock derivatives were designated as cash flow hedges to reduce variability in cash flows due to changes in interest payments attributable to increases or decreases in the benchmark interest rate during the period leading up to the probable issuance of fixed-rate debt. The fair value of interest rate lock derivatives as of December 31, 2019, was a liability of $1.2 billion and is included in Other current liabilities in our Consolidated Balance Sheets. See Note 7 – Fair Value Measurements for further information. Renewable Energy Purchase Agreements In April 2019, T-Mobile USA entered into a Renewable Energy Purchase Agreement (“REPA”) with a third party that is based on the expected operation of a solar photovoltaic electrical generation facility located in Texas and will remain in effect until the fifteenth anniversary of the facility’s entry into commercial operation. Commercial operation of the facility is expected to occur in July 2021. The REPA consists of an energy forward agreement that is net settled based on energy prices and the energy output generated by the facility. We have determined that the REPA does not meet the definition of a derivative because the expected energy output of the facility may not be reliably estimated (the arrangement lacks a notional amount). The REPA does not contain any unconditional purchase obligations because amounts under the agreement are not fixed and determinable. Our participation in the REPA did not require an upfront investment or capital commitment. We do not control the activities that most significantly impact the energy-generating facility, nor do we direct the use of, or receive specific energy output from, the facility. Contingencies and Litigation Litigation Matters On June 11, 2019, a number of state attorneys general filed a lawsuit against us, DT, Sprint, and SoftBank in the U.S. District Court for the Southern District of New York, alleging that the Merger, if consummated, would violate Section 7 of the Clayton Act and so should be enjoined. The trial concluded after two weeks of witness testimony and presentation of document evidence. We are now waiting for the trial court’s ruling. See Note 2 – Business Combinations for further information. In addition to the litigation associated with the Transactions discussed above, we are involved in various lawsuits and disputes, claims, government agency investigations and enforcement actions, and other proceedings (“Litigation Matters”) that arise in the ordinary course of business, which include claims of patent infringement (most of which are asserted by non-practicing entities primarily seeking monetary damages), class actions, and proceedings to enforce FCC rules and regulations. The Litigation Matters described above have progressed to various stages and some of them may proceed to trial, arbitration, hearing or other adjudication that could result in fines, penalties, or awards of monetary or injunctive relief in the coming 12 months if they are not otherwise resolved. We have established an accrual with respect to certain of these matters, where appropriate, which is reflected in the Consolidated Financial Statements but that is not considered to be, individually or in the aggregate, material. An accrual is established when we believe it is both probable that a loss has been incurred and an amount can be reasonably estimated. For other matters, where we have not determined that a loss is probable or because the amount of loss cannot be reasonably estimated, we have not recorded an accrual due to various factors typical in contested proceedings, including but not limited to uncertainty concerning legal theories and their resolution by courts or regulators, uncertain damage theories and demands, and a less than fully developed factual record. While we do not expect that the ultimate resolution of these proceedings, individually or in the aggregate, will have a material adverse effect on our financial position, an unfavorable outcome of some or all of these proceedings could have a material adverse impact on results of operations or cash flows for a particular period. This assessment is based on our current understanding of relevant facts and circumstances. As such, our view of these matters is subject to inherent uncertainties and may change in the future.

Additional Financial Informatio

Additional Financial Information	12 Months Ended
	Dec. 31, 2019
Supplemental Financial Statement Elements [Abstract]
Additional Financial Information	Note 17 – Additional Financial Information Supplemental Consolidated Balance Sheets Information Accounts Payable and Accrued Liabilities Accounts payable and accrued liabilities are summarized as follows: (in millions) December 31, 2019 December 31, 2018 Accounts payable $ 4,322 $ 5,487 Payroll and related benefits 802 709 Property and other taxes, including payroll 682 642 Interest 227 227 Commissions 251 243 Network decommissioning — 65 Toll and interconnect 156 157 Advertising 127 76 Other 179 135 Accounts payable and accrued liabilities $ 6,746 $ 7,741 Book overdrafts included in accounts payable and accrued liabilities were $463 million and $630 million as of December 31, 2019 and 2018, respectively. Supplemental Consolidated Statements of Comprehensive Income Information Related Party Transactions We have related party transactions associated with DT or its affiliates in the ordinary course of business, which are included in the Consolidated Financial Statements. The following table summarizes the impact of significant transactions with DT or its affiliates included in Operating expenses in the Consolidated Statements of Comprehensive Income: Year Ended December 31, (in millions) 2019 2018 2017 Discount related to roaming expenses $ (9) $ — $ — Fees incurred for use of the T-Mobile brand 88 84 79 Expenses for telecommunications and IT services — — 12 International long distance agreement 39 36 55 We have an agreement with DT for the reimbursement of certain administrative expenses, which were $11 million for each of the years ended December 31, 2019, 2018 and 2017.

Guarantor Financial Information

Guarantor Financial Information	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Guarantor Financial Information	Note 18 – Guarantor Financial Information Pursuant to the applicable indentures and supplemental indentures, the long-term debt to affiliates and third parties issued by T-Mobile USA (“Issuer”) is fully and unconditionally guaranteed, jointly and severally, on a senior unsecured basis by T-Mobile (“Parent”) and certain of the Issuer’s 100% owned subsidiaries (“Guarantor Subsidiaries”). The guarantees of the Guarantor Subsidiaries are subject to release in limited circumstances only upon the occurrence of certain customary conditions. The indentures and credit facilities governing the long-term debt contain covenants that, among other things, limit the ability of the Issuer and the Guarantor Subsidiaries to incur more debt, pay dividends and make distributions, make certain investments, repurchase stock, create liens or other encumbrances, enter into transactions with affiliates, enter into transactions that restrict dividends or distributions from subsidiaries, and merge, consolidate or sell, or otherwise dispose of, substantially all of their assets. Certain provisions of each of the credit facilities, indentures and supplemental indentures relating to the long-term debt restrict the ability of the Issuer to loan funds or make payments to Parent. However, the Issuer and Guarantor Subsidiaries are allowed to make certain permitted payments to the Parent under the terms of the indentures and the supplemental indentures. On October 23, 2018, SLMA LLC was formed as a limited liability company in Delaware to serve as an escrow subsidiary to facilitate the contemplated issuance of notes by Parent in connection with the Transactions. SLMA LLC is an indirect, 100% owned finance subsidiary of Parent, as such term is used in Rule 3-10(b) of Regulation S-X, and has been designated as an unrestricted subsidiary under the Issuer’s existing debt securities. Any debt securities that may be issued from time to time by SLMA LLC will be fully and unconditionally guaranteed by Parent. In 2019, certain Non-Guarantor Subsidiaries became Guarantor Subsidiaries. Certain prior period amounts have been reclassified to conform to the current period’s presentation. Presented below is the condensed consolidating financial information as of December 31, 2019 and 2018, and for the years ended December 31, 2019, 2018 and 2017. Condensed Consolidating Balance Sheet Information December 31, 2019 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Assets Current assets Cash and cash equivalents $ 5 $ 1 $ 1,350 $ 172 $ — $ 1,528 Accounts receivable, net — — 1,616 272 — 1,888 Equipment installment plan receivables, net — — 2,600 — — 2,600 Accounts receivable from affiliates — — 20 — — 20 Inventory — — 964 — — 964 Other current assets — 646 975 684 — 2,305 Total current assets 5 647 7,525 1,128 — 9,305 Property and equipment, net (1) — — 21,790 194 — 21,984 Operating lease right-of-use assets — — 10,933 — — 10,933 Financing lease right-of-use assets — — 2,715 — — 2,715 Goodwill — — 1,930 — — 1,930 Spectrum licenses — — 36,465 — — 36,465 Other intangible assets, net — — 115 — — 115 Investments in subsidiaries, net 28,898 51,306 — — (80,204) — Intercompany receivables and note receivables — 3,464 — — (3,464) — Equipment installment plan receivables due after one year, net — — 1,583 — — 1,583 Other assets — 18 1,797 239 (163) 1,891 Total assets $ 28,903 $ 55,435 $ 84,853 $ 1,561 $ (83,831) $ 86,921 Liabilities and Stockholders' Equity Current liabilities Accounts payable and accrued liabilities $ — $ 252 $ 6,236 $ 258 $ — $ 6,746 Payables to affiliates — 145 42 — — 187 Short-term debt — 25 — — — 25 Deferred revenue — — 631 — — 631 Short-term operating lease liabilities — — 2,287 — — 2,287 Short-term financing lease liabilities — — 957 — — 957 Other current liabilities — 1,171 139 363 — 1,673 Total current liabilities — 1,593 10,292 621 — 12,506 Long-term debt — 10,958 — — — 10,958 Long-term debt to affiliates — 13,986 — — — 13,986 Tower obligations (1) — — 75 2,161 — 2,236 Deferred tax liabilities — — 5,770 — (163) 5,607 Operating lease liabilities — — 10,539 — — 10,539 Financing lease liabilities — — 1,346 — — 1,346 Negative carrying value of subsidiaries, net — — 864 — (864) — Intercompany payables and debt 114 — 2,968 382 (3,464) — Other long-term liabilities — — 937 17 — 954 Total long-term liabilities 114 24,944 22,499 2,560 (4,491) 45,626 Total stockholders' equity (deficit) 28,789 28,898 52,062 (1,620) (79,340) 28,789 Total liabilities and stockholders' equity $ 28,903 $ 55,435 $ 84,853 $ 1,561 $ (83,831) $ 86,921 (1) Assets and liabilities for Non-Guarantor Subsidiaries are primarily included in VIEs related to the 2012 Tower Transaction. See Note 9 – Tower Obligations for further information. Condensed Consolidating Balance Sheet Information December 31, 2018 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Assets Current assets Cash and cash equivalents $ 2 $ 1 $ 1,082 $ 118 $ — $ 1,203 Accounts receivable, net — — 1,510 259 — 1,769 Equipment installment plan receivables, net — — 2,538 — — 2,538 Accounts receivable from affiliates — — 11 — — 11 Inventory — — 1,084 — — 1,084 Other current assets — — 1,032 644 — 1,676 Total current assets 2 1 7,257 1,021 — 8,281 Property and equipment, net (1) — — 23,113 246 — 23,359 Goodwill — — 1,901 — — 1,901 Spectrum licenses — — 35,559 — — 35,559 Other intangible assets, net — — 198 — — 198 Investments in subsidiaries, net 25,314 46,516 — — (71,830) — Intercompany receivables and note receivables — 5,174 — — (5,174) — Equipment installment plan receivables due after one year, net — — 1,547 — — 1,547 Other assets — 7 1,540 217 (141) 1,623 Total assets $ 25,316 $ 51,698 $ 71,115 $ 1,484 $ (77,145) $ 72,468 Liabilities and Stockholders' Equity Current liabilities Accounts payable and accrued liabilities $ — $ 228 $ 7,263 $ 250 $ — $ 7,741 Payables to affiliates — 157 43 — — 200 Short-term debt — — 841 — — 841 Deferred revenue — — 698 — — 698 Other current liabilities — 447 164 176 — 787 Total current liabilities — 832 9,009 426 — 10,267 Long-term debt — 10,950 1,174 — — 12,124 Long-term debt to affiliates — 14,582 — — — 14,582 Tower obligations (1) — — 384 2,173 — 2,557 Deferred tax liabilities — — 4,613 — (141) 4,472 Deferred rent expense — — 2,781 — — 2,781 Negative carrying value of subsidiaries, net — — 676 — (676) — Intercompany payables and debt 598 — 4,258 318 (5,174) — Other long-term liabilities — 20 926 21 — 967 Total long-term liabilities 598 25,552 14,812 2,512 (5,991) 37,483 Total stockholders' equity (deficit) 24,718 25,314 47,294 (1,454) (71,154) 24,718 Total liabilities and stockholders' equity $ 25,316 $ 51,698 $ 71,115 $ 1,484 $ (77,145) $ 72,468 (1) Assets and liabilities for Non-Guarantor Subsidiaries are primarily included in VIEs related to the 2012 Tower Transaction. See Note 9 – Tower Obligations for further information. Condensed Consolidating Statement of Comprehensive Income Information Year Ended December 31, 2019 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Revenues Service revenues $ — $ — $ 32,268 $ 3,003 $ (1,277) $ 33,994 Equipment revenues — — 10,053 3 (216) 9,840 Other revenues — 19 1,109 203 (167) 1,164 Total revenues — 19 43,430 3,209 (1,660) 44,998 Operating expenses Cost of services, exclusive of depreciation and amortization shown separately below — — 6,733 — (111) 6,622 Cost of equipment sales, exclusive of depreciation and amortization shown separately below — — 10,908 1,207 (216) 11,899 Selling, general and administrative — 16 14,467 989 (1,333) 14,139 Depreciation and amortization — — 6,564 52 — 6,616 Total operating expense — 16 38,672 2,248 (1,660) 39,276 Operating income — 3 4,758 961 — 5,722 Other income (expense) Interest expense — (454) (88) (185) — (727) Interest expense to affiliates — (409) (20) — 21 (408) Interest income — 22 20 3 (21) 24 Other (expense) income, net — (13) 6 (1) — (8) Total other expense, net — (854) (82) (183) — (1,119) Income (loss) before income taxes — (851) 4,676 778 — 4,603 Income tax expense — — (965) (170) — (1,135) Earnings of subsidiaries 3,468 4,319 31 — (7,818) — Net income $ 3,468 $ 3,468 $ 3,742 $ 608 $ (7,818) $ 3,468 Net income $ 3,468 $ 3,468 $ 3,742 $ 608 $ (7,818) $ 3,468 Other comprehensive (loss) income, net of tax Other comprehensive (loss) income, net of tax (536) (536) 186 — 350 (536) Total comprehensive income $ 2,932 $ 2,932 $ 3,928 $ 608 $ (7,468) $ 2,932 Condensed Consolidating Statement of Comprehensive Income Information Year Ended December 31, 2018 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Revenues Service revenues $ — $ — $ 30,637 $ 2,333 $ (978) $ 31,992 Equipment revenues — — 10,209 1 (201) 10,009 Other revenues — 29 1,113 228 (61) 1,309 Total revenues — 29 41,959 2,562 (1,240) 43,310 Operating expenses Cost of services, exclusive of depreciation and amortization shown separately below — — 6,283 24 — 6,307 Cost of equipment sales, exclusive of depreciation and amortization shown separately below — — 11,239 1,010 (202) 12,047 Selling, general and administrative — 11 13,296 892 (1,038) 13,161 Depreciation and amortization — — 6,422 64 — 6,486 Total operating expenses — 11 37,240 1,990 (1,240) 38,001 Operating income — 18 4,719 572 — 5,309 Other income (expense) Interest expense — (528) (114) (193) — (835) Interest expense to affiliates — (522) (21) — 21 (522) Interest income — 23 16 1 (21) 19 Other (expense) income, net — (87) 33 — — (54) Total other expense, net — (1,114) (86) (192) — (1,392) Income (loss) before income taxes — (1,096) 4,633 380 — 3,917 Income tax expense — — (950) (79) — (1,029) Earnings of subsidiaries 2,888 3,984 32 — (6,904) — Net income $ 2,888 $ 2,888 $ 3,715 $ 301 $ (6,904) $ 2,888 Net income $ 2,888 $ 2,888 $ 3,715 $ 301 $ (6,904) $ 2,888 Other comprehensive (loss) income, net of tax Other comprehensive (loss) income, net of tax (332) (332) 116 — 216 (332) Total comprehensive income $ 2,556 $ 2,556 $ 3,831 $ 301 $ (6,688) $ 2,556 Condensed Consolidating Statement of Comprehensive Income Information Year Ended December 31, 2017 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Revenues Service revenues $ — $ — $ 28,894 $ 2,113 $ (847) $ 30,160 Equipment revenues — — 9,620 — (245) 9,375 Other revenues — 3 879 212 (25) 1,069 Total revenues — 3 39,393 2,325 (1,117) 40,604 Operating expenses Cost of services, exclusive of depreciation and amortization shown separately below — — 6,076 24 — 6,100 Cost of equipment sales, exclusive of depreciation and amortization shown separately below — — 10,849 1,003 (244) 11,608 Selling, general and administrative — — 12,276 856 (873) 12,259 Depreciation and amortization — — 5,914 70 — 5,984 Gains on disposal of spectrum licenses — — (235) — — (235) Total operating expenses — — 34,880 1,953 (1,117) 35,716 Operating income — 3 4,513 372 — 4,888 Other income (expense) Interest expense — (811) (109) (191) — (1,111) Interest expense to affiliates — (560) (23) — 23 (560) Interest income 1 29 10 — (23) 17 Other income (expense), net — (88) 16 (1) — (73) Total other income (expense), net 1 (1,430) (106) (192) — (1,727) Income (loss) before income taxes 1 (1,427) 4,407 180 — 3,161 Income tax expense (benefit) — — 1,527 (152) — 1,375 Earnings (loss) of subsidiaries 4,535 5,962 (57) — (10,440) — Net income 4,536 4,535 5,877 28 (10,440) 4,536 Dividends on preferred stock (55) — — — — (55) Net income attributable to common stockholders $ 4,481 $ 4,535 $ 5,877 $ 28 $ (10,440) $ 4,481 Net income $ 4,536 $ 4,535 $ 5,877 $ 28 $ (10,440) $ 4,536 Other comprehensive loss, net of tax Other comprehensive loss, net of tax 7 7 7 — (14) 7 Total comprehensive income $ 4,543 $ 4,542 $ 5,884 $ 28 $ (10,454) $ 4,543 Condensed Consolidating Statement of Cash Flows Information Year Ended December 31, 2019 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Operating activities Net cash (used in) provided by operating activities $ — $ (752) $ 11,338 $ (3,207) $ (555) $ 6,824 Investing activities Purchases of property and equipment — — (6,391) — — (6,391) Purchases of spectrum licenses and other intangible assets, including deposits — — (967) — — (967) Proceeds from sales of tower sites — — 38 — — 38 Proceeds related to beneficial interests in securitization transactions — — 37 3,839 — 3,876 Net cash related to derivative contracts under collateral exchange arrangements — (632) — — — (632) Acquisition of companies, net of cash acquired — (32) 1 — — (31) Other, net — (12) (6) — — (18) Net cash (used in) provided by investing activities — (676) (7,288) 3,839 — (4,125) Financing activities Proceeds from borrowing on revolving credit facility, net — 2,340 — — — 2,340 Repayments of revolving credit facility — — (2,340) — — (2,340) Repayments of financing lease obligations — — (798) — — (798) Repayments of short-term debt for purchases of inventory, property and equipment, net — — (775) — — (775) Repayments of long-term debt — — (600) — — (600) Intercompany advances, net 1 (912) 934 (23) — — Tax withholdings on share-based awards — — (156) — — (156) Cash payments for debt prepayment or debt extinguishment costs — — (28) — — (28) Intercompany dividend paid — — — (555) 555 — Other, net 2 — (19) — — (17) Net cash provided (used in) by financing activities 3 1,428 (3,782) (578) 555 (2,374) Change in cash and cash equivalents 3 — 268 54 — 325 Cash and cash equivalents Beginning of period 2 1 1,082 118 — 1,203 End of period $ 5 $ 1 $ 1,350 $ 172 $ — $ 1,528 Condensed Consolidating Statement of Cash Flows Information Year Ended December 31, 2018 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Operating activities Net cash (used in) provided by operating activities $ — $ (1,254) $ 10,414 $ (5,041) $ (220) $ 3,899 Investing activities Purchases of property and equipment — — (5,536) (5) — (5,541) Purchases of spectrum licenses and other intangible assets, including deposits — — (127) — — (127) Proceeds related to beneficial interests in securitization transactions — — 53 5,353 — 5,406 Acquisition of companies, net of cash — — (338) — — (338) Equity investment in subsidiary — — (43) — 43 — Other, net — (7) 28 — — 21 Net cash (used in) provided by investing activities — (7) (5,963) 5,348 43 (579) Financing activities Proceeds from issuance of long-term debt — 2,494 — — — 2,494 Proceeds from borrowing on revolving credit facility, net — 6,265 — — — 6,265 Repayments of revolving credit facility — — (6,265) — — (6,265) Repayments of financing lease obligations — — (700) — — (700) Repayments of short-term debt for purchases of inventory, property and equipment, net — — (300) — — (300) Repayments of long-term debt — — (3,349) — — (3,349) Repurchases of common stock (1,071) — — — — (1,071) Intercompany advances, net 995 (7,498) 6,530 (27) — — Equity investment from parent — — 43 — (43) — Tax withholdings on share-based awards — — (146) — — (146) Cash payments for debt prepayment or debt extinguishment costs — — (212) — — (212) Intercompany dividend paid — — — (220) 220 — Other, net 4 — (56) — — (52) Net cash (used in) provided by financing activities (72) 1,261 (4,455) (247) 177 (3,336) Change in cash and cash equivalents (72) — (4) 60 — (16) Cash and cash equivalents Beginning of period 74 1 1,086 58 — 1,219 End of period $ 2 $ 1 $ 1,082 $ 118 $ — $ 1,203 Condensed Consolidating Statement of Cash Flows Information Year Ended December 31, 2017 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Operating activities Net cash provided by (used in) operating activities $ 1 $ (1,613) $ 9,761 $ (4,218) $ (100) $ 3,831 Investing activities Purchases of property and equipment — — (5,237) — — (5,237) Purchases of spectrum licenses and other intangible assets, including deposits — — (5,828) — — (5,828) Proceeds related to beneficial interests in securitization transactions — — 43 4,276 — 4,319 Equity investment in subsidiary (308) — — — 308 — Other, net — — 1 — — 1 Net cash (used in) provided by investing activities (308) — (11,021) 4,276 308 (6,745) Financing activities Proceeds from issuance of long-term debt — 10,480 — — — 10,480 Proceeds from borrowing on revolving credit facility, net — 2,910 — — — 2,910 Repayments of revolving credit facility — — (2,910) — — (2,910) Repayments of financing lease obligations — — (486) — — (486) Repayments of short-term debt for purchases of inventory, property and equipment, net — — (300) — — (300) Repayments of long-term debt — — (10,230) — — (10,230) Repurchases of common stock (427) — — — — (427) Intercompany advances, net 484 (14,817) 14,300 33 — — Equity investment from parent — 308 — — (308) — Tax withholdings on share-based awards — — (166) — — (166) Dividends on preferred stock (55) — — — — (55) Cash payments for debt prepayment or debt extinguishment costs — — (188) — — (188) Intercompany dividend paid — — — (100) 100 — Other, net 21 — (16) — — 5 Net cash provided by (used in) financing activities 23 (1,119) 4 (67) (208) (1,367) Change in cash and cash equivalents (284) (2,732) (1,256) (9) — (4,281) Cash and cash equivalents Beginning of period 358 2,733 2,342 67 — 5,500 End of period $ 74 $ 1 $ 1,086 $ 58 $ — $ 1,219

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information [Abstract]
Quarterly Financial Information (Unaudited)	Supplementary Data Quarterly Financial Information (Unaudited) (in millions, except share and per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Full Year 2019 Total revenues $ 11,080 $ 10,979 $ 11,061 $ 11,878 $ 44,998 Operating income 1,476 1,541 1,471 1,234 5,722 Net income 908 939 870 751 3,468 Net income attributable to common stockholders 908 939 870 751 3,468 Earnings per share Basic $ 1.07 $ 1.10 $ 1.02 $ 0.88 $ 4.06 Diluted $ 1.06 $ 1.09 $ 1.01 $ 0.87 $ 4.02 Weighted average shares outstanding Basic 851,223,498 854,368,443 854,578,241 856,294,467 854,143,751 Diluted 858,643,481 860,135,593 862,690,751 864,158,739 863,433,511 2018 Total revenues $ 10,455 $ 10,571 $ 10,839 $ 11,445 $ 43,310 Operating income 1,282 1,450 1,440 1,137 5,309 Net income 671 782 795 640 2,888 Net income attributable to common stockholders 671 782 795 640 2,888 Earnings per share Basic $ 0.78 $ 0.92 $ 0.94 $ 0.75 $ 3.40 Diluted $ 0.78 $ 0.92 $ 0.93 $ 0.75 $ 3.36 Weighted average shares outstanding Basic 855,222,664 847,660,488 847,087,120 849,102,785 849,744,152 Diluted 862,244,084 852,040,670 853,852,764 856,344,347 858,290,174 Earnings per share is computed independently for each quarter and the sum of the quarters may not equal earnings per share for the full year.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business T-Mobile US, Inc. (“T-Mobile,” “we,” “our,” “us” or the “Company”), together with its consolidated subsidiaries, is a leading provider of mobile communications services, including voice, messaging and data, under its flagship brands, T-Mobile and Metro™ by T-Mobile ("Metro by T-Mobile"), in the United States (“U.S.”), Puerto Rico and the U.S. Virgin Islands. All of our revenues were earned in, and all of our long-lived assets are located in, the U.S., Puerto Rico and the U.S. Virgin Islands. We provide mobile communications services primarily using our 4G Long-Term Evolution (“LTE”) network and our newly deployed 5G technology network. We also offer a wide selection of wireless devices, including handsets, tablets and other mobile communication devices, and accessories for sale, as well as financing through Equipment Installment Plans (“EIP”) and leasing through JUMP! On Demand™. Additionally, we provide reinsurance for handset insurance policies and extended warranty contracts offered to our mobile communications customers.
Basis of Accounting	The consolidated financial statements include the balances and results of operations of T-Mobile and our consolidated subsidiaries. We consolidate majority-owned subsidiaries over which we exercise control, as well as variable interest entities (“VIE”) where we are deemed to be the primary beneficiary and VIEs, which cannot be deconsolidated, such as those related to Tower obligations. Intercompany transactions and balances have been eliminated in consolidation. We operate as a single operating segment. The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires our management to make estimates and assumptions which affect the financial statements and accompanying notes.
Use of Estimates	Estimates are based on historical experience, where applicable, and other assumptions which our management believes are reasonable under the circumstances. These estimates are inherently subject to judgment and actual results could differ from these estimates.
Reclassification	Certain prior year amounts have been reclassified to conform to the current year's presentation. See “Accounting Pronouncements Adopted During the Current Year” below.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents consist of highly liquid money market funds and U.S. Treasury securities with remaining maturities of three months or less at the date of purchase.
Receivables and Allowance for Credit Losses	Receivables and Allowance for Credit Losses Accounts receivable consist primarily of amounts currently due from customers, other carriers and third-party retail channels. Accounts receivable not held for sale are reported in the balance sheet at outstanding principal adjusted for any charge-offs and the allowance for credit losses. Accounts receivable held for sale are reported at the lower of amortized cost or fair value. We have an arrangement to sell the majority of service accounts receivable on a revolving basis, which are treated as sales of financial assets. We offer certain retail customers the option to pay for their devices and certain other purchases in installments typically over a period of 24, but up to 36, months using an EIP. EIP receivables not held for sale are reported in our Consolidated Balance Sheets at outstanding principal adjusted for any charge-offs, allowance for credit losses and unamortized discounts. At the time of an installment sale, we impute a discount for interest if the EIP term exceeds 12 months as there is no stated rate of interest on the EIP receivables. The EIP receivables are recorded at their present value, which is determined by discounting future cash payments at the imputed interest rate. The difference between the recorded amount of the EIP receivables and their unpaid principal balance (i.e., the contractual amount due from the customer) results in a discount which is allocated to the performance obligations in the arrangement and recorded as a reduction in transaction price in Total service revenues and Equipment revenues in our Consolidated Statements of Comprehensive Income. We determine the imputed discount rate based primarily on current market interest rates and the estimated credit risk on the EIP receivables. As a result, we do not recognize a separate credit loss allowance at the time of issuance as the effects of uncertainty about future cash flows resulting from credit risk are included in the initial present value measurement of the receivable. The imputed discount on EIP receivables is amortized over the financed installment term using the effective interest method and recognized as Other revenues in our Consolidated Statements of Comprehensive Income. Subsequent to the initial determination of the imputed discount, we assess the need for and, if necessary, recognize an allowance for credit losses to the extent the amount of estimated probable losses on the gross EIP receivable balances exceed the remaining unamortized imputed discount balances. Total imputed discount and allowances were approximately 7.0% and 8.1% of the total amount of gross accounts receivable, including EIP receivables, at December 31, 2019 and 2018, respectively. The current portion of the EIP receivables is included in Equipment installment plan receivables, net and the long-term portion of the EIP receivables is included in Equipment installment plan receivables due after one year, net in our Consolidated Balance Sheets. We have an arrangement to sell certain EIP receivables on a revolving basis, which are treated as sales of financial assets. We maintain an allowance for credit losses and determine its appropriateness through an established process that assesses the losses inherent in our receivables portfolio. We develop and document our allowance methodology at the portfolio segment level - accounts receivable portfolio and EIP receivable portfolio segments. While we attribute portions of the allowance to our respective accounts receivable and EIP portfolio segments, the entire allowance is available to absorb credit losses inherent in the total receivables portfolio. Our process involves procedures to appropriately consider the unique risk characteristics of our accounts receivable and EIP receivable portfolio segments. For each portfolio segment, losses are estimated collectively for groups of receivables with similar characteristics. Our allowance levels are influenced by receivable volumes, receivable delinquency status, historical loss experience and other conditions influencing loss expectations, such as macro-economic conditions.
Inventories	Inventories Inventories consist primarily of wireless devices and accessories, which are valued at the lower of cost or net realizable value. Cost is determined using standard cost which approximates average cost. Shipping and handling costs paid to wireless device and accessories vendors, and costs to refurbish used devices recovered through our device upgrade programs are included in the standard cost of inventory. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. We record inventory write-downs to net realizable value for obsolete and slow-moving items based on inventory turnover trends and historical experience.
Long-Lived Assets and Property and Equipment	Long-Lived Assets Long-lived assets include assets that do not have indefinite lives, such as property and equipment and other intangible assets. All of our long-lived assets are located in the U.S., including Puerto Rico and the U.S. Virgin Islands. We assess potential impairments to our long-lived assets when events or changes in circumstances indicate the carrying amount of the asset may not be recoverable. If any indicators of impairment are present, we test recoverability. The carrying value of a long-lived asset or asset group is not recoverable if it exceeds the sum of the undiscounted cash flows expected to be generated from the use and eventual disposition of the asset or asset group. If the undiscounted cash flows do not exceed the asset or asset group’s carrying amount, then an impairment loss is recorded, measured as the amount by which the carrying amount of a long-lived asset or asset group exceeds its fair value. Property and Equipment Property and equipment consists of buildings and equipment, wireless communications systems, leasehold improvements, capitalized software, leased wireless devices and construction in progress. Buildings and equipment include certain network server equipment. Wireless communications systems include assets to operate our wireless network and IT data centers, including tower assets and leasehold improvements and assets related to the liability for the retirement of long-lived assets. Leasehold improvements include asset improvements other than those related to the wireless network. Property and equipment are recorded at cost less accumulated depreciation and impairments, if any, in Property and equipment, net on our Consolidated Balance Sheets. We generally depreciate property and equipment over the period the property and equipment provide economic benefit. Depreciable life studies are performed periodically to confirm the appropriateness of depreciable lives for certain categories of property and equipment. These studies take into account actual usage, physical wear and tear, replacement history and assumptions about technology evolution. When these factors indicate the useful life of an asset is different from the previous assessment, the remaining book value is depreciated prospectively over the adjusted remaining estimated useful life. Leasehold improvements are depreciated over the shorter of their estimated useful lives or the related lease term. JUMP! On Demand allows customers to lease a device over a period of up to 18 months and upgrade it for a new device up to one time per month. To date, all of our leased devices were classified as operating leases. At operating lease inception, leased wireless devices are transferred from inventory to property and equipment. Leased wireless devices are depreciated to their estimated residual value over the period expected to provide utility to us, which is generally shorter than the lease term and considers expected losses. Revenues associated with the leased wireless devices, net of incentives, are generally recognized over the lease term. Upon device upgrade or at lease end, customers must return or purchase their device. Returned devices transferred from Property and equipment, net are recorded as inventory and are valued at the lower of cost or net realizable value with any write-down recognized as Cost of equipment sales in our Consolidated Statements of Comprehensive Income. Costs of major replacements and improvements are capitalized. Repair and maintenance expenditures which do not enhance or extend the asset’s useful life are charged to operating expenses as incurred. Construction costs, labor and overhead incurred in the expansion or enhancement of our wireless network are capitalized. Capitalization commences with pre-construction period administrative and technical activities, which includes obtaining leases, zoning approvals and building permits, and ceases at the point at which the asset is ready for its intended use. We capitalize interest associated with the acquisition or construction of certain property and equipment. Capitalized interest is reported as a reduction in interest expense and depreciated over the useful life of the related assets.
Asset Retirement Obligations	We record an asset retirement obligation for the fair value of legal obligations associated with the retirement of tangible long-lived assets and a corresponding increase in the carrying amount of the related asset in the period in which the obligation is incurred. In periods subsequent to initial measurement, we recognize changes in the liability resulting from the passage of time and revisions to either the timing or the amount of the original estimate. Over time, the liability is accreted to its present value and the capitalized cost is depreciated over the estimated useful life of the asset. Our obligations relate primarily to certain legal obligations to remediate leased property on which our network infrastructure and administrative assets are located.
Software Capitalization	We capitalize certain costs incurred in connection with developing or acquiring internal use software. Capitalization of software costs commences once the final selection of the specific software solution has been made and management authorizes and commits to funding the software project. Capitalized software costs are included in Property and equipment, net in our Consolidated Balance Sheets and are amortized on a straight-line basis over the estimated useful life of the asset. Costs incurred during the preliminary project stage, as well as maintenance and training costs, are expensed as incurred.
Other Intangible Assets	Other Intangible Assets Intangible assets that do not have indefinite useful lives are amortized over their estimated useful lives. Customer lists are amortized using the sum-of-the-years'-digits method over the expected period in which the relationship is expected to contribute to future cash flows. The remaining finite-lived intangible assets are amortized using the straight-line method.
Goodwill	Goodwill Goodwill consists of the excess of the purchase price over the fair value of identifiable net assets acquired in a business combination. Goodwill is allocated to our two reporting units, wireless and Layer3.
Spectrum Licenses	Spectrum Licenses Spectrum licenses are carried at costs incurred to acquire the spectrum licenses and the costs to prepare the spectrum licenses for their intended use, such as costs to clear acquired spectrum licenses. The Federal Communications Commission (“FCC”) issues spectrum licenses which provide us with the exclusive right to utilize designated radio frequency spectrum within specific geographic service areas to provide wireless communications services. While spectrum licenses are issued for a fixed period of time, typically for up to fifteen years, the FCC has granted license renewals routinely and at a nominal cost. The spectrum licenses held by us expire at various dates. We believe we will be able to meet all requirements necessary to secure renewal of our spectrum licenses at nominal costs. Moreover, we determined there are currently no legal, regulatory, contractual, competitive, economic or other factors that limit the useful lives of our spectrum licenses. Therefore, we determined the spectrum licenses should be treated as indefinite-lived intangible assets.
Impairment	Impairment We assess the carrying value of our goodwill and other indefinite-lived intangible assets, such as our spectrum licenses, for potential impairment annually as of December 31, or more frequently if events or changes in circumstances indicate such assets might be impaired. When assessing goodwill for impairment we may elect to first perform a qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. If we do not perform a qualitative assessment, or if the qualitative assessment indicates it is more likely than not that the fair value of the two reporting units, wireless and Layer3, is less than its carrying amount, we perform a quantitative test. We recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized would not exceed the total amount of goodwill allocated to that reporting unit. We test our spectrum licenses for impairment on an aggregate basis, consistent with our management of the overall business at a national level. We may elect to first perform a qualitative assessment to determine whether it is more likely than not that the fair value of an intangible asset is less than its carrying value. If we do not perform the qualitative assessment, or if the qualitative assessment indicates it is more likely than not that the fair value of the intangible asset is less than its carrying amount, we calculate the estimated fair value of the intangible asset. If the estimated fair value of the spectrum licenses is lower than their carrying amount, an impairment loss is recognized for the difference. We estimate fair value using the Greenfield methodology, which is an income approach based on discounted cash flows associated with the intangible asset, to estimate the price at which an orderly transaction to sell the asset would take place between market participants at the measurement date under current market conditions.
Guarantee Liabilities	Guarantee Liabilities We offer a device trade-in program, Just Upgrade My Phone (“JUMP!”), which provides eligible customers a specified-price trade-in right to upgrade their device. Upon enrollment, participating customers must finance the purchase of a device on an EIP and have a qualifying T-Mobile monthly wireless service plan, which is treated as an arrangement with multiple performance obligations when entered into at or near the same time. Upon a qualifying JUMP! program upgrade, the customer’s remaining EIP balance is settled provided they trade-in their eligible used device in good working condition and purchase a new device from us on a new EIP. For customers who enroll in JUMP!, we recognize a liability and reduce revenue for the portion of revenue which represents the estimated fair value of the specified-price trade-in right guarantee. The guarantee liability is valued based on various economic and customer behavioral assumptions, which requires judgment, including estimating the customer's remaining EIP balance at trade-in, the expected fair value of the used device at trade-in, and the probability and timing of trade-in. When customers upgrade their device, the difference between the EIP balance credit to the customer and the fair value of the returned device is recorded against the guarantee liabilities. All assumptions are reviewed periodically.
Fair Value Measurements	Fair Value Measurements We carry certain assets and liabilities at fair value. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three-tier hierarchy for inputs used in measuring fair value, which prioritizes the inputs based on the observability as of the measurement date, is as follows: Level 1 Quoted prices in active markets for identical assets or liabilities; Level 2 Observable inputs other than the quoted prices in active markets for identical assets and liabilities; and Level 3 Unobservable inputs for which there is little or no market data, which require us to develop assumptions of what market participants would use in pricing the asset or liability. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the placement of assets and liabilities being measured within the fair value hierarchy. The carrying values of cash and cash equivalents, short-term investments, accounts receivable, accounts receivable from affiliates and accounts payable approximate fair value due to the short-term maturities of these instruments. The carrying values of EIP receivables approximate fair value as the receivables are recorded at their present value, net of unamortized discount and allowance for credit losses. There were no financial instruments with a carrying value materially different from their fair value, based on quoted market prices or rates for the same or similar instruments, or internal valuation models.
Derivative Financial Instruments	Derivative Financial Instruments Derivative financial instruments are recognized as either assets or liabilities and are measured at fair value. We do not use derivatives for trading or speculative purposes. For derivative instruments designated as cash flow hedges associated with forecasted debt issuances, changes in fair value are reported as a component of Accumulated other comprehensive loss until reclassified into Interest expense in the same period the hedged transaction affects earnings, generally over the life of the related debt. Unrealized gains on derivatives designated as cash flow hedges are recorded at fair value as assets, and unrealized losses on derivatives designated as cash flow hedges are recorded at fair value as liabilities.
Revenue Recognition	Revenue Recognition (effective January 1, 2018) We primarily generate our revenue from providing wireless services to customers and selling or leasing devices and accessories. Our contracts with customers may involve multiple performance obligations, which include wireless services, wireless devices or a combination thereof, and we allocate the transaction price between each performance obligation based on its relative standalone selling price. Significant Judgments The most significant judgments affecting the amount and timing of revenue from contracts with our customers include the following items: • Revenue for service contracts that we assess are not probable of collection is not recognized until the contract is completed or terminated and cash is received. Collectibility is re-assessed when there is a significant change in facts or circumstances. Our assessment of collectibility considers whether we may limit our exposure to credit risk through our right to stop transferring additional service in the event the customer is delinquent as well as certain contract terms such as down payments that reduce our exposure to credit risk. Customer credit behavior is inherently uncertain. See “Receivables and Allowance for Credit Losses”, above, for more discussion on how we assess credit risk. • Promotional EIP bill credits offered to a customer on an equipment sale that are paid over time and are contingent on the customer maintaining a service contract may result in an extended service contract based on whether a substantive penalty is deemed to exist. Determining whether contingent EIP bill credits result in a substantive termination penalty may require significant judgment. • The identification of distinct performance obligations within our service plans may require significant judgment. • Revenue is recorded net of costs paid to another party for performance obligations where we arrange for the other party to transfer goods or services to the customer (i.e., when we are acting as an agent). For example, performance obligations relating to services provided by third-party content providers where we neither control a right to the content provider’s service nor control the underlying service itself are presented net because we are acting as an agent. The determination of whether we control the underlying service or right to the service prior to our transfer to the customer requires, at times, significant judgment. • For transactions where we recognize a significant financing component, judgment is required to determine the discount rate. For EIP sales, the discount rate used to adjust the transaction price primarily reflects current market interest rates and the estimated credit risk of the customer. Customer credit behavior is inherently uncertain. See “Receivables and Allowance for Credit Losses”, above, for more discussion on how we assess credit risk. • Our products are generally sold with a right of return, which is accounted for as variable consideration when estimating the amount of revenue to recognize. Device return levels are estimated based on the expected value method as there are a large number of contracts with similar characteristics and the outcome of each contract is independent of the others. Historical return rate experience is a significant input to our expected value methodology. • Sales of equipment to indirect dealers who have been identified as our customer (referred to as the sell-in model) often include credits subsequently paid to the dealer as a reimbursement for any discount promotions offered to the end consumer. These credits (payments to a customer) are accounted for as variable consideration when estimating the amount of revenue to recognize from the sales of equipment to indirect dealers and are estimated based on historical experience and other factors, such as expected promotional activity. • The determination of the standalone selling price for contracts that involve more than one performance obligation may require significant judgment, such as when the selling price of a good or service is not readily observable. • For capitalized contract costs, determining the amortization period over which such costs are recognized as well as assessing the indicators of impairment may require significant judgment. Wireless Services Revenue We generate our wireless services revenues from providing access to, and usage of, our wireless communications network. Service revenues also include revenues earned for providing value added services to customers, such as handset insurance services. Service contracts are billed monthly either in advance or arrears, or are prepaid. Generally, service revenue is recognized as we satisfy our performance obligation to transfer service to our customers. We typically satisfy our stand-ready performance obligations, including unlimited wireless services, evenly over the contract term. For usage-based and prepaid wireless services, we satisfy our performance obligations when services are rendered. Consideration payable to a customer is treated as a reduction of the total transaction price, unless the payment is in exchange for a distinct good or service, such as certain commissions paid to dealers. Federal Universal Service Fund (“USF”) and other fees are assessed by various governmental authorities in connection with the services we provide to our customers and are included in Cost of services. When we separately bill and collect these regulatory fees from customers, they are recorded gross in Total service revenues in our Consolidated Statements of Comprehensive Income. For the years ended December 31, 2019, 2018 and 2017, we recorded approximately $93 million, $161 million and $258 million, respectively, of USF fees on a gross basis. We have made an accounting policy election to exclude from the measurement of the transaction price all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by us from a customer (e.g., sales, use, value added, and some excise taxes). Equipment Revenues We generate equipment revenues from the sale or lease of mobile communication devices and accessories. For performance obligations related to equipment contracts, we typically transfer control at a point in time when the device or accessory is delivered to, and accepted by, the customer or dealer. We have elected to account for shipping and handling activities that occur after control of the related good transfers as fulfillment activities instead of assessing such activities as performance obligations. We estimate variable consideration (e.g., device returns or certain payments to indirect dealers) primarily based on historical experience. Equipment sales not probable of collection are generally recorded as payments are received. Our assessment of collectibility considers contract terms such as down payments that reduce our exposure to credit risk. We offer certain customers the option to pay for devices and accessories in installments using an EIP. Generally, we recognize as a reduction of the total transaction price the effects of a financing component in contracts where customers purchase their devices and accessories on an EIP with a term of more than one year, including those financing components that are not considered to be significant to the contract. However, we have elected the practical expedient to not recognize the effects of a significant financing component for contracts where we expect, at contract inception, that the period between the transfer of a performance obligation to a customer and the customer’s payment for that performance obligation will be one year or less. In addition, for customers who enroll in our JUMP! program, we recognize a liability based on the estimated fair value of the specified-price trade-in right guarantee. The fair value of the guarantee is deducted from the transaction price and the remaining transaction price is allocated to other elements of the contract, including service and equipment performance obligations. See “Guarantee Liabilities” above for further information. JUMP! On Demand allows customers to lease a device over a period of up to 18 months and upgrade it for a new device up to one time per month. To date, all of our leased wireless devices are accounted for as operating leases and estimated contract consideration is allocated between lease elements and non-lease elements (such as service and equipment performance obligations) based on the relative standalone selling price of each performance obligation in the contract. Lease revenues are recorded as equipment revenues and recognized as earned on a straight-line basis over the lease term. Lease revenues on contracts not probable of collection are limited to the amount of payments received. See “Property and Equipment” above for further information. Contract Balances Generally, our devices and service plans are available at standard prices, which are maintained on price lists and published on our website and/or within our retail stores. For contracts that involve more than one product or service that are identified as separate performance obligations, the transaction price is allocated to the performance obligations based on their relative standalone selling prices. The standalone selling price is the price at which we would sell the good or service separately to a customer and is most commonly evidenced by the price at which we sell that good or service separately in similar circumstances and to similar customers. A contract asset is recorded when revenue is recognized in advance of our right to receive consideration (i.e., we must perform additional services in order to receive consideration). Amounts are recorded as receivables when our right to consideration is unconditional. When consideration is received, or we have an unconditional right to consideration in advance of delivery of goods or services, a contract liability is recorded. The transaction price can include non-refundable upfront fees, which are allocated to the identifiable performance obligations. Contract assets are included in Other current assets and Other assets and contract liabilities are included in Deferred revenue in our Consolidated Balance Sheets. Contract Modifications Our service contracts allow customers to frequently modify their contracts without incurring penalties in many cases. Each time a contract is modified, we evaluate the change in scope or price of the contract to determine if the modification should be treated as a separate contract, as if there is a termination of the existing contract and creation of a new contract, or if the modification should be considered a change associated with the existing contract. We typically do not have significant impacts from contract modifications. Contract Costs We incur certain incremental costs to obtain a contract that we expect to recover, such as sales commissions. We record an asset when these incremental costs to obtain a contract are incurred and amortize them on a systematic basis that is consistent with the transfer to the customer of the goods or services to which the asset relates. We amortize deferred costs incurred to obtain service contracts on a straight-line basis over the term of the initial contract and anticipated renewal contracts to which the costs relate, currently 24 months for postpaid service contracts. However, we have elected the practical expedient permitting expensing of costs to obtain a contract when the expected amortization period is one year or less for prepaid service contracts. Incremental costs to obtain equipment contracts (e.g., commissions paid on device and accessory sales) are recognized when the equipment is transferred to the customer. See Note 1 - Summary of Significant Accounting Policies included in our Annual Report on Form 10-K for the year ended December 31, 2017 for more discussion regarding the accounting policies that governed revenue recognition prior to January 1, 2018.
Advertising Expense	Advertising ExpenseWe expense the cost of advertising and other promotional expenditures to market our services and products as incurred.
Income Taxes	Income Taxes Deferred tax assets and liabilities are recognized based on temporary differences between the financial statement and tax bases of assets and liabilities using enacted tax rates expected to be in effect when these differences are realized. A valuation allowance is recorded when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The ultimate realization of a deferred tax asset depends on the ability to generate sufficient taxable income of the appropriate character and in the appropriate taxing jurisdictions within the carryforward periods available. We account for uncertainty in income taxes recognized in the financial statements in accordance with the accounting guidance for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. We assess whether it is more likely than not that a tax position will be sustained upon examination based on the technical merits of the position and adjust the unrecognized tax benefits in light of changes in facts and circumstances, such as changes in tax law, interactions with taxing authorities and developments in case law.
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) Other comprehensive income (loss) consists of adjustments, net of tax, related to unrealized gains (losses) on cash flow hedges and available-for-sale securities. This is reported in Accumulated other comprehensive loss as a separate component of stockholders’ equity until realized in earnings.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation cost for stock awards, which include restricted stock units (“RSUs”) and performance-based restricted stock units (“PRSUs”), is measured at fair value on the grant date and recognized as expense, net of expected forfeitures, over the related service period. The fair value of stock awards is based on the closing price of our common stock on the date of grant. RSUs are recognized as expense using the straight-line method. PRSUs are recognized as expense following a graded vesting schedule with their performance re-assessed and updated on a quarterly basis, or more frequently as changes in facts and circumstances warrant.
Earnings Per Share	Earnings Per ShareBasic earnings per share is computed by dividing Net income attributable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted earnings per share is computed by giving effect to all potentially dilutive common shares outstanding during the period. Potentially dilutive common shares consist of outstanding stock options, RSUs and PRSUs, calculated using the treasury stock method, and prior to the conversion of our preferred stock in December 2017, potentially dilutive common shares included mandatory convertible preferred stock calculated using the if-converted method.
Variable Interest Entities	Variable Interest Entities VIEs are entities that lack sufficient equity to permit the entity to finance its activities without additional subordinated financial support from other parties, have equity investors that do not have the ability to make significant decisions relating to the entity's operations through voting rights, do not have the obligation to absorb the expected losses or do not have the right to receive the residual returns of the entity. The most common type of VIE is a special purpose entity (“SPE”). SPEs are commonly used in securitization transactions in order to isolate certain assets and distribute the cash flows from those assets to investors. SPEs are generally structured to insulate investors from claims on the SPE's assets by creditors of other entities, including the creditors of the seller of the assets. The primary beneficiary is required to consolidate the assets and liabilities of the VIE. The primary beneficiary is the party which has both the power to direct the activities of an entity that most significantly impact the VIE's economic performance, and through its interests in the VIE, the obligation to absorb losses or the right to receive benefits from the VIE which could potentially be significant to the VIE. We consolidate VIEs when we are deemed to be the primary beneficiary or when the VIE cannot be deconsolidated. In assessing which party is the primary beneficiary, all the facts and circumstances are considered, including each party’s role in establishing the VIE and its ongoing rights and responsibilities. This assessment includes, first, identifying the activities that most significantly impact the VIE’s economic performance; and second, identifying which party, if any, has power over those activities. In general, the parties that make the most significant decisions affecting the VIE (such as asset managers and servicers) or have the right to unilaterally remove those decision-makers are deemed to have the power to direct the activities of a VIE.
Accounting Pronouncements Adopted During the Current Year/Accounting Pronouncements Not Yet Adopted	Accounting Pronouncements Adopted During the Current Year Leases In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02, “Leases (Topic 842),” and has since modified the standard with several ASUs (collectively, the “new lease standard”). The new lease standard was effective for us, and we adopted the standard, on January 1, 2019. We adopted the standard by recognizing and measuring leases at the adoption date with a cumulative effect of initially applying the guidance recognized at the date of initial application and as a result did not restate the prior periods presented in the Consolidated Financial Statements. The new lease standard provides for a number of optional practical expedients in transition. We did not elect the “package of practical expedients” and as a result reassessed under the new lease standard our prior accounting conclusions about lease identification, lease classification and initial direct costs. We elected to use hindsight for determining the reasonably certain lease term. We did not elect the practical expedient pertaining to land easements as it is not applicable to us. The new lease standard provides practical expedients and policy elections for an entity’s ongoing accounting. Generally, we elected the practical expedient to not separate lease and non-lease components in arrangements whereby we are the lessee. For arrangements in which we are the lessor of wireless devices, we did not elect this practical expedient. We did not elect the short-term lease recognition exemption, which includes the recognition of right-of-use assets and lease liabilities for existing short-term leases at transition. We have also applied this election to all active leases at transition. The most significant judgments and impacts upon adoption of the standard include the following: • In evaluating contracts to determine if they qualify as a lease, we consider factors such as if we have obtained or transferred substantially all of the rights to the underlying asset through exclusivity, if we can or if we have transferred the ability to direct the use of the asset by making decisions about how and for what purpose the asset will be used and if the lessor has substantive substitution rights. • We recognized right-of-use assets and operating lease liabilities for operating leases that have not previously been recorded. The lease liability for operating leases is based on the net present value of future minimum lease payments. The right-of-use asset for operating leases is based on the lease liability adjusted for the reclassification of certain balance sheet amounts such as prepaid rent and deferred rent, which we remeasured at adoption due to the application of hindsight to our lease term estimates. Deferred and prepaid rent are no longer presented separately. • Capital lease assets previously included within Property and equipment, net were reclassified to financing lease right-of-use assets, and capital lease liabilities previously included in Short-term debt and Long-term debt were reclassified to financing lease liabilities in our Consolidated Balance Sheet. • Certain line items in the Consolidated Statements of Cash Flows and the “Supplemental disclosure of cash flow information” have been renamed to align with the new terminology presented in the new lease standard; “Repayment of capital lease obligations” is now presented as “Repayments of financing lease obligations” and “Assets acquired under capital lease obligations” is now presented as “Financing lease right-of-use assets obtained in exchange for lease obligations.” In the “Operating Activities” section of the Consolidated Statements of Cash Flows we have added “Operating lease right-of-use assets” and “Short and long-term operating lease liabilities” which represent the change in the operating lease asset and liability, respectively. Additionally, in the “Supplemental disclosure of cash flow information” section of the Consolidated Statements of Cash Flows we have added “Operating lease payments,” and in the “Noncash investing and financing activities” section we have added “Operating lease right-of-use assets obtained in exchange for lease obligations.” • In determining the discount rate used to measure the right-of-use asset and lease liability, we use rates implicit in the lease, or if not readily available, we use our incremental borrowing rate. Our incremental borrowing rate is based on an estimated secured rate comprised of a risk-free LIBOR rate plus a credit spread as secured by our assets. Determining a credit spread as secured by our assets may require significant judgment. • Certain of our lease agreements include rental payments based on changes in the consumer price index (“CPI”). Lease liabilities are not remeasured as a result of changes in the CPI; instead, changes in the CPI are treated as variable lease payments and are excluded from the measurement of the right-of-use asset and lease liability. These payments are recognized in the period in which the related obligation was incurred. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. • We elected the use of hindsight whereby we applied current lease term assumptions that are applied to new leases in determining the expected lease term period for all cell sites. Upon adoption of the new lease standard and application of hindsight, our expected lease term has shortened to reflect payments due for the initial non-cancelable lease term only. This assessment corresponds to our lease term assessment for new leases and aligns with the payments that have been disclosed as lease commitments in prior years. As a result, the average remaining lease term for cell sites has decreased from approximately nine • We were also required to reassess the previously failed sale-leasebacks of certain T-Mobile-owned wireless communications tower sites and determine whether the transfer of the assets to the tower operator under the arrangement met the transfer of control criteria in the revenue standard and whether a sale should be recognized. Determining whether the transfer of control criteria has been met requires significant judgement. • We concluded that a sale has not occurred for the 6,200 tower sites transferred to Crown Castle International Corp. (“CCI”) pursuant to a master prepaid lease arrangement; therefore, these sites will continue to be accounted for as failed sale-leasebacks. • We concluded that a sale should be recognized for the 900 tower sites transferred to CCI pursuant to the sale of a subsidiary and for the 500 tower sites transferred to Phoenix Tower International (“PTI”). Upon adoption on January 1, 2019, we derecognized our existing long-term financial obligation and the tower-related property and equipment associated with these 1,400 previously failed sale-leaseback tower sites and recognized a lease liability and right-of-use asset for the leaseback of the tower sites. The impacts from the change in accounting conclusion are primarily a decrease in Other revenues of $44 million and a decrease in Interest expense of $34 million in fiscal year 2019. • Rental revenues and expenses associated with co-location tower sites are presented on a net basis under the new lease standard. These revenues and expenses were presented on a gross basis under the former lease standard. Including the impacts from a change in the accounting conclusion on the 1,400 previously failed sale-leaseback tower sites, the cumulative effect of initially applying the new lease standard on January 1, 2019 is as follows: January 1, 2019 (in millions) Beginning Balance Cumulative Effect Adjustment Beginning Balance, As Adjusted Assets Other current assets $ 1,676 $ (78) $ 1,598 Property and equipment, net 23,359 (2,339) 21,020 Operating lease right-of-use assets — 9,251 9,251 Financing lease right-of-use assets — 2,271 2,271 Other intangible assets, net 198 (12) 186 Other assets 1,623 (71) 1,552 Liabilities and Stockholders’ Equity Accounts payable and accrued liabilities 7,741 (65) 7,676 Other current liabilities 787 28 815 Short-term and long-term debt 12,965 (2,015) 10,950 Tower obligations 2,557 (345) 2,212 Deferred tax liabilities 4,472 231 4,703 Deferred rent expense 2,781 (2,781) — Short-term and long-term operating lease liabilities — 11,364 11,364 Short-term and long-term financing lease liabilities — 2,016 2,016 Other long-term liabilities 967 (64) 903 Accumulated deficit (12,954) 653 (12,301) Including the impacts from the change in the accounting conclusion on the 1,400 previously failed sale-leaseback tower sites and the change in presentation on the income statement of the 6,200 tower sites for which a sale did not occur, the cumulative effects of initially applying the new lease standard for the year ended December 31, 2019 are estimated as follows: • The aggregate impact is a decrease in Other revenues of $185 million, a decrease in Total operating expenses of $380 million, a decrease in Interest expense of $34 million and an increase to Net income of $175 million. • The impact on our Consolidated Statements of Cash Flows is a decrease in Net cash provided by operating activities of $10 million and a decrease in Net cash used in financing activities of $10 million. For arrangements where we are the lessor, including arrangements to lease devices to our service customers, the adoption of the new lease standard did not have a material impact on our financial statements as these leases are classified as operating leases. Device lease payments are presented as Equipment revenues and recognized as earned on a straight-line basis over the lease term. Recognition of equipment revenue on lease contracts that are determined to not be probable of collection is limited to the amount of payments received. We have made an accounting policy election to exclude from the consideration in the contract all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by us from a customer (e.g., sales, use, value added, and some excise taxes). At operating lease inception, leased wireless devices are transferred from Inventory to Property and equipment, net. Leased wireless devices are depreciated to their estimated residual value over the period expected to provide utility to us, which is generally shorter than the lease term and considers expected losses. Returned devices transferred from Property and equipment, net, are recorded as Inventory and are valued at the lower of cost or market with any write-down to market recognized as Cost of equipment sales in our Consolidated Statements of Comprehensive Income. We do not have any leasing transactions with related parties. See Note 1 5 - Leases for further information. We have implemented significant new lease accounting systems, processes and internal controls over lease accounting to assist us in the application of the new lease standard.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Financial Statement Impacts of Applying New Accounting Standard	Including the impacts from a change in the accounting conclusion on the 1,400 previously failed sale-leaseback tower sites, the cumulative effect of initially applying the new lease standard on January 1, 2019 is as follows: January 1, 2019 (in millions) Beginning Balance Cumulative Effect Adjustment Beginning Balance, As Adjusted Assets Other current assets $ 1,676 $ (78) $ 1,598 Property and equipment, net 23,359 (2,339) 21,020 Operating lease right-of-use assets — 9,251 9,251 Financing lease right-of-use assets — 2,271 2,271 Other intangible assets, net 198 (12) 186 Other assets 1,623 (71) 1,552 Liabilities and Stockholders’ Equity Accounts payable and accrued liabilities 7,741 (65) 7,676 Other current liabilities 787 28 815 Short-term and long-term debt 12,965 (2,015) 10,950 Tower obligations 2,557 (345) 2,212 Deferred tax liabilities 4,472 231 4,703 Deferred rent expense 2,781 (2,781) — Short-term and long-term operating lease liabilities — 11,364 11,364 Short-term and long-term financing lease liabilities — 2,016 2,016 Other long-term liabilities 967 (64) 903 Accumulated deficit (12,954) 653 (12,301)

Receivables and Allowance for_2

Receivables and Allowance for Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Schedule of Equipment Installment Plan Receivables	The following table summarizes the EIP receivables, including imputed discounts and related allowance for credit losses: (in millions) December 31, 2019 December 31, 2018 EIP receivables, gross $ 4,582 $ 4,534 Unamortized imputed discount (299) (330) EIP receivables, net of unamortized imputed discount 4,283 4,204 Allowance for credit losses (100) (119) EIP receivables, net $ 4,183 $ 4,085 Classified on the balance sheet as: Equipment installment plan receivables, net $ 2,600 $ 2,538 Equipment installment plan receivables due after one year, net 1,583 1,547 EIP receivables, net $ 4,183 $ 4,085
Schedule of Unamortized Imputed Discount and Allowance for Credit Losses for Equipment Installment Plan Receivables	Activity for the years ended December 31, 2019, 2018 and 2017, in the allowance for credit losses and unamortized imputed discount balances for the accounts receivable and EIP receivables segments were as follows: December 31, 2019 December 31, 2018 December 31, 2017 (in millions) Accounts Receivable Allowance EIP Receivables Allowance Total Accounts Receivable Allowance EIP Receivables Allowance Total Accounts Receivable Allowance EIP Receivables Allowance Total Allowance for credit losses and imputed discount, beginning of period $ 67 $ 449 $ 516 $ 86 $ 396 $ 482 $ 102 $ 316 $ 418 Bad debt expense 77 230 307 69 228 297 104 284 388 Write-offs, net of recoveries (83) (249) (332) (88) (240) (328) (120) (273) (393) Change in imputed discount on short-term and long-term EIP receivables N/A 136 136 N/A 250 250 N/A 252 252 Impact on the imputed discount from sales of EIP receivables N/A (167) (167) N/A (185) (185) N/A (183) (183) Allowance for credit losses and imputed discount, end of period $ 61 $ 399 $ 460 $ 67 $ 449 $ 516 $ 86 $ 396 $ 482
Schedule of Equipment Installment Plan Receivables by Credit Category	The following table provides delinquency status for the unpaid principal balance for receivables within the EIP portfolio segment, which we actively monitor as part of our current credit risk management practices and policies: December 31, 2019 December 31, 2018 (in millions) Prime Subprime Total EIP Receivables, gross Prime Subprime Total EIP Receivables, gross Current - 30 days past due $ 2,384 $ 2,108 $ 4,492 $ 1,987 $ 2,446 $ 4,433 31 - 60 days past due 13 28 41 15 32 47 61 - 90 days past due 7 17 24 6 19 25 More than 90 days past due 7 18 25 7 22 29 Total receivables, gross $ 2,411 $ 2,171 $ 4,582 $ 2,015 $ 2,519 $ 4,534

Sales of Certain Receivables (T

Sales of Certain Receivables (Tables)	12 Months Ended
	Dec. 31, 2019
Transfers and Servicing [Abstract]
Schedule of Variable Interest Entities	The following table summarizes the carrying amounts and classification of assets, which consists primarily of the deferred purchase price and liabilities included in our Consolidated Balance Sheets that relate to our variable interest in the Service VIE: (in millions) December 31, 2019 December 31, 2018 Other current assets $ 350 $ 339 Accounts payable and accrued liabilities 25 59 Other current liabilities 342 149
Schedule of variable interest entities - EIP	The following table summarizes the carrying amounts and classification of assets, which consists primarily of the deferred purchase price, and liabilities included in our Consolidated Balance Sheets that relate to the EIP BRE: (in millions) December 31, 2019 December 31, 2018 Other current assets $ 344 $ 321 Other assets 89 88 Other long-term liabilities 18 22
Schedule of Factoring Arrangement	The following table summarizes the impact of the sale of certain service receivables and EIP receivables in our Consolidated Balance Sheets: (in millions) December 31, 2019 December 31, 2018 Derecognized net service receivables and EIP receivables $ 2,584 $ 2,577 Other current assets 694 660 of which, deferred purchase price 692 658 Other long-term assets 89 88 of which, deferred purchase price 89 88 Accounts payable and accrued liabilities 25 59 Other current liabilities 342 149 Other long-term liabilities 18 22 Net cash proceeds since inception 1,944 1,879 Of which: Change in net cash proceeds during the year-to-date period 65 (179) Net cash proceeds funded by reinvested collections 1,879 2,058

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	The components of property and equipment were as follows: (in millions) Useful Lives December 31, 2019 December 31, 2018 Buildings and equipment Up to 40 years $ 2,587 $ 2,428 Wireless communications systems Up to 20 years 34,353 35,282 Leasehold improvements Up to 12 years 1,345 1,299 Capitalized software Up to 10 years 12,705 11,712 Leased wireless devices Up to 18 months 1,139 1,159 Construction in progress 2,973 2,776 Accumulated depreciation and amortization (33,118) (31,297) Property and equipment, net $ 21,984 $ 23,359
Schedule of Asset Retirement Obligations	Activity in our asset retirement obligations was as follows: (in millions) December 31, 2019 December 31, 2018 Asset retirement obligations, beginning of year $ 609 $ 562 Liabilities incurred 35 26 Liabilities settled (2) (9) Accretion expense 32 30 Changes in estimated cash flows (15) — Asset retirement obligations, end of year $ 659 $ 609 Classified on the balance sheet as: Other long-term liabilities $ 659 $ 609

Goodwill, Spectrum License Tr_2

Goodwill, Spectrum License Transactions and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amount of goodwill for the years ended December 31, 2019 and 2018, are as follows: (in millions) Goodwill Historical goodwill $ 12,449 Goodwill from acquisition of Layer3 TV 218 Accumulated impairment losses at December 31, 2018 (10,766) Balance as of December 31, 2018 1,901 Goodwill from acquisition in 2019 29 Balance as of December 31, 2019 $ 1,930 Accumulated impairment losses at December 31, 2019 $ (10,766)
Schedule of Spectrum Licenses	The following table summarizes our spectrum license activity for the years ended December 31, 2019 and 2018: (in millions) 2019 2018 Spectrum licenses, beginning of year $ 35,559 $ 35,366 Spectrum license acquisitions 857 138 Spectrum licenses transferred to held for sale — (1) Costs to clear spectrum 49 56 Spectrum licenses, end of year $ 36,465 $ 35,559
Schedule of Other Intangible Assets	The components of Other intangible assets were as follows: Useful Lives December 31, 2019 December 31, 2018 (in millions) Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Customer lists Up to 6 years $ 1,104 $ (1,104) $ — $ 1,104 $ (1,086) $ 18 Trademarks and patents Up to 19 years 323 (258) 65 312 (225) 87 Other Up to 28 years 100 (50) 50 149 (56) 93 Other intangible assets $ 1,527 $ (1,412) $ 115 $ 1,565 $ (1,367) $ 198
Schedule of Estimated Aggregate Future Amortization Expense	The estimated aggregate future amortization expense for intangible assets subject to amortization are summarized below: (in millions) Estimated Future Amortization Year Ending December 31, 2020 $ 83 2021 14 2022 3 2023 3 2024 3 Thereafter 9 Total $ 115

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Carrying Values and Fair Values of Long-term Debt	The carrying amounts and fair values of our assets measured at fair value on a recurring basis included in our Consolidated Balance Sheets were as follows: Level within the Fair Value Hierarchy December 31, 2019 December 31, 2018 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Assets: Deferred purchase price assets 3 $ 781 $ 781 $ 746 $ 746 The carrying amounts and fair values of our short-term and long-term debt included in our Consolidated Balance Sheets were as follows: Level within the Fair Value Hierarchy December 31, 2019 December 31, 2018 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Liabilities: Senior Notes to third parties 1 $ 10,958 $ 11,479 $ 10,950 $ 10,945 Senior Notes to affiliates 2 9,986 10,366 9,984 9,802 Incremental Term Loan Facility to affiliates 2 4,000 4,000 4,000 3,976 Senior Reset Notes to affiliates 2 — — 598 640

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Debt	Debt was as follows: (in millions) December 31, December 31, 5.300% Senior Notes to affiliates due 2021 $ 2,000 $ 2,000 4.000% Senior Notes to affiliates due 2022 1,000 1,000 4.000% Senior Notes due 2022 500 500 Incremental term loan facility to affiliates due 2022 2,000 2,000 6.000% Senior Notes due 2023 1,300 1,300 9.332% Senior Reset Notes to affiliates due 2023 — 600 6.000% Senior Notes due 2024 1,000 1,000 6.500% Senior Notes due 2024 1,000 1,000 6.000% Senior Notes to affiliates due 2024 1,350 1,350 6.000% Senior Notes to affiliates due 2024 650 650 Incremental term loan facility to affiliates due 2024 2,000 2,000 5.125% Senior Notes to affiliates due 2025 1,250 1,250 5.125% Senior Notes due 2025 500 500 6.375% Senior Notes due 2025 1,700 1,700 6.500% Senior Notes due 2026 2,000 2,000 4.500% Senior Notes due 2026 1,000 1,000 4.500% Senior Notes to affiliates due 2026 1,000 1,000 5.375% Senior Notes due 2027 500 500 5.375% Senior Notes to affiliates due 2027 1,250 1,250 4.750% Senior Notes due 2028 1,500 1,500 4.750% Senior Notes to affiliates due 2028 1,500 1,500 Capital leases (1) — 2,015 Unamortized premium on debt to affiliates 43 52 Unamortized discount on Senior Notes to affiliates (53) (64) Financing arrangements for property and equipment 25 — Debt issuance costs and consent fees (46) (56) Total debt 24,969 27,547 Less: Current portion of capital leases — 841 Less: Financing arrangements for property and equipment 25 — Total long-term debt $ 24,944 $ 26,706 Classified on the balance sheet as: Long-term debt $ 10,958 $ 12,124 Long-term debt to affiliates 13,986 14,582 Total long-term debt $ 24,944 $ 26,706 (1) Capital lease liabilities previously included in Short-term debt and Long-term debt were reclassified to Financing lease liabilities in our Consolidated Balance Sheet. See Note 1 – Summary of Significant Accounting Policies for additional details.
Debt Instrument Redemption	During the year ended December 31, 2019, we made the following note redemption: (in millions) Principal Amount Write -off of Embedded Derivatives (1) Other (2) Redemption Redemption Price 9.332% Senior Notes due 2023 $ 600 $ 11 $ 28 April 28, 2019 104.6660 % (1) Certain components of the reset features were required to be bifurcated from the DT Senior Reset Notes and separately accounted for as embedded derivative instruments. The write-off of embedded derivatives upon redemption resulted in a gain and is included in Other expense, net in our Consolidated Statements of Comprehensive Income and in Losses on redemption of debt within Net cash provided by operating activities in our Consolidated Statements of Cash Flows. (2) Cash for the premium portion of the redemption price set forth in the indenture governing the DT Senior Reset Notes, plus accrued but unpaid interest on the DT Senior Reset Notes. The redemption premium was included in Other expense, net in our Consolidated Statements of Comprehensive Income and in Cash payments for debt prepayment or debt extinguishment costs in our Consolidated Statements of Cash Flows.
Schedule of Letters of Credit	The following table summarizes the outstanding standby letters of credit under each agreement: (in millions) December 31, 2019 December 31, 2018 JP Morgan Chase $ 20 $ 20 Deutsche Bank 93 66 Total outstanding balance $ 113 $ 86

Tower Obligations (Tables)

Tower Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Summary of Impacts to Consolidated Balance Sheets	The following table summarizes the balances of the failed sale-leasebacks in the Consolidated Balance Sheets: (in millions) December 31, 2019 December 31, 2018 Property and equipment, net $ 198 $ 329 Tower obligations 2,236 2,557

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	Branded postpaid service revenues, including branded postpaid phone revenues and branded postpaid other revenues, were as follows: Year Ended December 31, (in millions) 2019 2018 2017 Branded postpaid service revenues Branded postpaid phone revenues $ 21,329 $ 19,745 $ 18,371 Branded postpaid other revenues 1,344 1,117 1,077 Total branded postpaid service revenues $ 22,673 $ 20,862 $ 19,448 Equipment revenues from the lease of mobile communication devices were as follows: Year Ended December 31, (in millions) 2019 2018 2017 Equipment revenues from the lease of mobile communication devices $ 599 $ 692 $ 877
Schedule of Contract Liability and Receivable Balances	The opening and closing balances of our contract asset and contract liability balances from contracts with customers as of December 31, 2018 and December 31, 2019, were as follows: (in millions) Contract Assets Contract Liabilities Balance as of December 31, 2018 $ 51 $ 645 Balance as of December 31, 2019 63 560 Change $ 12 $ (85) Revenues for the years ended December 31, 2019 and 2018, include the following: Year Ended December 31, (in millions) 2019 2018 Amounts included in the beginning of year contract liability balance $ 643 $ 710

Employee Compensation and Ben_2

Employee Compensation and Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Stock-based Compensation Expense and Related Income Tax Benefits	Stock-based compensation expense and related income tax benefits were as follows: (in millions, except shares, per share and contractual life amounts) December 31, 2019 December 31, 2018 December 31, 2017 Stock-based compensation expense $ 495 $ 424 $ 306 Income tax benefit related to stock-based compensation $ 92 $ 81 $ 73 Weighted average fair value per stock award granted $ 73.25 $ 61.52 $ 60.21 Unrecognized compensation expense $ 515 $ 547 $ 445 Weighted average period to be recognized (years) 1.6 1.8 1.9 Fair value of stock awards vested $ 512 $ 471 $ 503
Schedule of RSU and PRSU Awards Activity	Time-Based Restricted Stock Units and Restricted Stock Awards (in millions, except shares, per share and contractual life amounts) Number of Units or Awards Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Nonvested, December 31, 2018 11,010,635 $ 57.66 1.0 $ 700 Granted 6,099,719 73.13 Vested (5,862,128) 55.52 Forfeited (745,015) 65.87 Nonvested, December 31, 2019 10,503,211 67.31 0.9 824 Performance-Based Restricted Stock Units and Restricted Stock Awards (in millions, except shares, per share and contractual life amounts) Number of Units or Awards Weighted Average Grant Date Fair Value Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Nonvested, December 31, 2018 3,851,554 $ 64.03 1.6 $ 245 Granted 1,046,792 73.98 Vested (1,006,404) 52.47 Forfeited (88,403) 62.02 Nonvested, December 31, 2019 3,803,539 69.78 1.0 300 PRSUs included in the table above are shown at target. Share payout can range from 0% to 200% based on different performance outcomes.
Schedule of Stock Options Activity	The following activity occurred under the Stock Option Plans: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Outstanding at December 31, 2018 284,811 $ 14.58 3.8 Exercised (85,083) 15.94 Expired/canceled (4,786) 22.75 Outstanding at December 31, 2019 194,942 13.80 2.9 Exercisable at December 31, 2019 180,966 13.48 2.6

Repurchases of Common Stock (Ta

Repurchases of Common Stock (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule of Repurchases of Common Stock	The following table summarizes information regarding repurchases of our common stock under the 2017 Stock Repurchase Program: (In millions, except shares and per share price) Year ended December 31, Number of Shares Repurchased Average Price Paid Per Share Total Purchase Price 2018 16,738,758 $ 62.96 $ 1,054 2017 7,010,889 63.34 444 23,749,647 63.07 $ 1,498

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax	Our sources of Income before income taxes were as follows: Year Ended December 31, (in millions) 2019 2018 2017 U.S. $ 4,557 $ 3,686 $ 3,274 Puerto Rico 46 231 (113) Income before income taxes $ 4,603 $ 3,917 $ 3,161
Schedule of Components of Income Tax Expense (Benefit)	Income tax (expense) benefit is summarized as follows: Year Ended December 31, (in millions) 2019 2018 2017 Current tax benefit (expense) Federal $ 24 $ 39 $ — State (70) (63) (28) Puerto Rico 2 (25) (1) Total current tax expense (44) (49) (29) Deferred tax benefit (expense) Federal (954) (750) 1,182 State (125) (160) 173 Puerto Rico (12) (70) 49 Total deferred tax (expense) benefit (1,091) (980) 1,404 Total income tax (expense) benefit $ (1,135) $ (1,029) $ 1,375
Schedule of Effective Income Tax Rate Reconciliation	The reconciliation between the U.S. federal statutory income tax rate and our effective income tax rate is as follows: Year Ended December 31, 2019 2018 2017 Federal statutory income tax rate 21.0 % 21.0 % 35.0 % Effect of law and rate changes 0.4 1.9 (68.9) Change in valuation allowance (1.8) (1.6) (11.4) State taxes, net of federal benefit 5.1 4.8 4.8 Equity-based compensation (0.6) (0.6) (2.4) Puerto Rico taxes, net of federal benefit 0.3 2.4 (1.5) Permanent differences 1.2 1.3 0.5 Federal tax credits, net of reserves (0.8) (2.9) 0.3 Other, net (0.1) — 0.1 Effective income tax rate 24.7 % 26.3 % (43.5) %
Schedule of Deferred Tax Assets and Liabilities	Significant components of deferred income tax assets and liabilities, tax effected, are as follows: (in millions) December 31, December 31, Deferred tax assets Loss carryforwards $ 823 $ 1,526 Deferred rents — 784 Lease liability 3,403 — Reserves and accruals 659 668 Federal and state tax credits 331 340 Other 903 620 Deferred tax assets, gross 6,119 3,938 Valuation allowance (129) (210) Deferred tax assets, net 5,990 3,728 Deferred tax liabilities Spectrum licenses 5,902 5,494 Property and equipment 2,506 2,434 Lease right-of-use assets 2,881 — Other intangible assets 19 40 Other 289 232 Total deferred tax liabilities 11,597 8,200 Net deferred tax liabilities $ 5,607 $ 4,472 Classified on the balance sheet as: Deferred tax liabilities $ 5,607 $ 4,472
Schedule of Unrecognized Tax Benefits Roll Forward	A reconciliation of the beginning and ending amount of unrecognized tax benefits were as follows: Year Ended December 31, (in millions) 2019 2018 2017 Unrecognized tax benefits, beginning of year $ 462 $ 412 $ 410 Gross (decreases) increases to tax positions in prior periods (7) 6 (10) Gross increases due to current period business acquisitions — 10 — Gross increases to current period tax positions 59 34 12 Unrecognized tax benefits, end of year $ 514 $ 462 $ 412

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share	The computation of basic and diluted earnings per share was as follows: Year Ended December 31, (in millions, except shares and per share amounts) 2019 2018 2017 Net income $ 3,468 $ 2,888 $ 4,536 Less: Dividends on mandatory convertible preferred stock — — (55) Net income attributable to common stockholders - basic 3,468 2,888 4,481 Add: Dividends related to mandatory convertible preferred stock — — 55 Net income attributable to common stockholders $ 3,468 $ 2,888 $ 4,536 Weighted average shares outstanding - basic 854,143,751 849,744,152 831,850,073 Effect of dilutive securities: Outstanding stock options and unvested stock awards 9,289,760 8,546,022 9,200,873 Mandatory convertible preferred stock — — 30,736,504 Weighted average shares outstanding - diluted 863,433,511 858,290,174 871,787,450 Earnings per share - basic $ 4.06 $ 3.40 $ 5.39 Earnings per share - diluted $ 4.02 $ 3.36 $ 5.20 Potentially dilutive securities: Outstanding stock options and unvested stock awards 16,359 148,422 33,980

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Components of Lease Expense	The components of lease expense were as follows: (in millions) Year Ended December 31, 2019 Operating lease expense $ 2,558 Financing lease expense: Amortization of right-of-use assets 523 Interest on lease liabilities 82 Total financing lease expense 605 Variable lease expense 243 Total lease expense $ 3,406
Schedule of Information Relating to Lease Term and Discount Rate	Information relating to the lease term and discount rate is as follows: December 31, 2019 Weighted Average Remaining Lease Term (Years) Operating leases 6 Financing leases 3 Weighted Average Discount Rate Operating leases 4.8 % Financing leases 4.0 %
Maturity Schedule of Operating Lease Liabilities	Maturities of lease liabilities as of December 31, 2019, were as follows: (in millions) Operating Leases Finance Leases Twelve Months Ending December 31, 2020 $ 2,754 $ 1,013 2021 2,583 733 2022 2,311 414 2023 1,908 101 2024 1,615 71 Thereafter 3,797 115 Total lease payments 14,968 2,447 Less imputed interest 2,142 144 Total $ 12,826 $ 2,303
Maturity Schedule of Finance Lease Liabilities	Maturities of lease liabilities as of December 31, 2019, were as follows: (in millions) Operating Leases Finance Leases Twelve Months Ending December 31, 2020 $ 2,754 $ 1,013 2021 2,583 733 2022 2,311 414 2023 1,908 101 2024 1,615 71 Thereafter 3,797 115 Total lease payments 14,968 2,447 Less imputed interest 2,142 144 Total $ 12,826 $ 2,303
Schedule of Leased Wireless Devices	The components of leased wireless devices under our JUMP! On Demand program were as follows: (in millions) December 31, 2019 December 31, 2018 Leased wireless devices, gross $ 1,139 $ 1,159 Accumulated depreciation (407) (622) Leased wireless devices, net $ 732 $ 537
Schedule of Future Minimum Payments Expected to be Received (under 842)	Future minimum payments expected to be received over the lease term related to the leased wireless devices, which exclude optional residual buy-out amounts at the end of the lease term, are summarized below: (in millions) Total Twelve Months Ending December 31, 2020 $ 417 2021 99 Total $ 516
Schedule of Future Minimum Payments Expected to be Received (under 840)	As of December 31, 2018, the future minimum payments expected to be received over the lease term related to the leased wireless devices, which exclude optional residual buy-out amounts at the end of the lease term, are summarized below: (in millions) Total Year Ended December 31, 2019 $ 419 2020 59 Total $ 478
Schedule of Future Minimum Lease Payments for Capital Leases	As of December 31, 2018, the future minimum payments required under capital leases, including interest and maintenance, over their remaining terms are summarized below: (in millions) Future Minimum Payments Year Ended December 31, 2019 $ 909 2020 631 2021 389 2022 102 2023 66 Thereafter 106 Total $ 2,203 Included in Total Interest $ 143 Maintenance 45

Additional Financial Informat_2

Additional Financial Information (Tables)	12 Months Ended
	Dec. 31, 2019
Supplemental Financial Statement Elements [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	Accounts payable and accrued liabilities are summarized as follows: (in millions) December 31, 2019 December 31, 2018 Accounts payable $ 4,322 $ 5,487 Payroll and related benefits 802 709 Property and other taxes, including payroll 682 642 Interest 227 227 Commissions 251 243 Network decommissioning — 65 Toll and interconnect 156 157 Advertising 127 76 Other 179 135 Accounts payable and accrued liabilities $ 6,746 $ 7,741
Schedule of Related Party Transactions	The following table summarizes the impact of significant transactions with DT or its affiliates included in Operating expenses in the Consolidated Statements of Comprehensive Income: Year Ended December 31, (in millions) 2019 2018 2017 Discount related to roaming expenses $ (9) $ — $ — Fees incurred for use of the T-Mobile brand 88 84 79 Expenses for telecommunications and IT services — — 12 International long distance agreement 39 36 55

Guarantor Financial Informati_2

Guarantor Financial Information (Tables)	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Schedule of Condensed Consolidating Balance Sheet Information	Condensed Consolidating Balance Sheet Information December 31, 2019 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Assets Current assets Cash and cash equivalents $ 5 $ 1 $ 1,350 $ 172 $ — $ 1,528 Accounts receivable, net — — 1,616 272 — 1,888 Equipment installment plan receivables, net — — 2,600 — — 2,600 Accounts receivable from affiliates — — 20 — — 20 Inventory — — 964 — — 964 Other current assets — 646 975 684 — 2,305 Total current assets 5 647 7,525 1,128 — 9,305 Property and equipment, net (1) — — 21,790 194 — 21,984 Operating lease right-of-use assets — — 10,933 — — 10,933 Financing lease right-of-use assets — — 2,715 — — 2,715 Goodwill — — 1,930 — — 1,930 Spectrum licenses — — 36,465 — — 36,465 Other intangible assets, net — — 115 — — 115 Investments in subsidiaries, net 28,898 51,306 — — (80,204) — Intercompany receivables and note receivables — 3,464 — — (3,464) — Equipment installment plan receivables due after one year, net — — 1,583 — — 1,583 Other assets — 18 1,797 239 (163) 1,891 Total assets $ 28,903 $ 55,435 $ 84,853 $ 1,561 $ (83,831) $ 86,921 Liabilities and Stockholders' Equity Current liabilities Accounts payable and accrued liabilities $ — $ 252 $ 6,236 $ 258 $ — $ 6,746 Payables to affiliates — 145 42 — — 187 Short-term debt — 25 — — — 25 Deferred revenue — — 631 — — 631 Short-term operating lease liabilities — — 2,287 — — 2,287 Short-term financing lease liabilities — — 957 — — 957 Other current liabilities — 1,171 139 363 — 1,673 Total current liabilities — 1,593 10,292 621 — 12,506 Long-term debt — 10,958 — — — 10,958 Long-term debt to affiliates — 13,986 — — — 13,986 Tower obligations (1) — — 75 2,161 — 2,236 Deferred tax liabilities — — 5,770 — (163) 5,607 Operating lease liabilities — — 10,539 — — 10,539 Financing lease liabilities — — 1,346 — — 1,346 Negative carrying value of subsidiaries, net — — 864 — (864) — Intercompany payables and debt 114 — 2,968 382 (3,464) — Other long-term liabilities — — 937 17 — 954 Total long-term liabilities 114 24,944 22,499 2,560 (4,491) 45,626 Total stockholders' equity (deficit) 28,789 28,898 52,062 (1,620) (79,340) 28,789 Total liabilities and stockholders' equity $ 28,903 $ 55,435 $ 84,853 $ 1,561 $ (83,831) $ 86,921 (1) Assets and liabilities for Non-Guarantor Subsidiaries are primarily included in VIEs related to the 2012 Tower Transaction. See Note 9 – Tower Obligations for further information. Condensed Consolidating Balance Sheet Information December 31, 2018 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Assets Current assets Cash and cash equivalents $ 2 $ 1 $ 1,082 $ 118 $ — $ 1,203 Accounts receivable, net — — 1,510 259 — 1,769 Equipment installment plan receivables, net — — 2,538 — — 2,538 Accounts receivable from affiliates — — 11 — — 11 Inventory — — 1,084 — — 1,084 Other current assets — — 1,032 644 — 1,676 Total current assets 2 1 7,257 1,021 — 8,281 Property and equipment, net (1) — — 23,113 246 — 23,359 Goodwill — — 1,901 — — 1,901 Spectrum licenses — — 35,559 — — 35,559 Other intangible assets, net — — 198 — — 198 Investments in subsidiaries, net 25,314 46,516 — — (71,830) — Intercompany receivables and note receivables — 5,174 — — (5,174) — Equipment installment plan receivables due after one year, net — — 1,547 — — 1,547 Other assets — 7 1,540 217 (141) 1,623 Total assets $ 25,316 $ 51,698 $ 71,115 $ 1,484 $ (77,145) $ 72,468 Liabilities and Stockholders' Equity Current liabilities Accounts payable and accrued liabilities $ — $ 228 $ 7,263 $ 250 $ — $ 7,741 Payables to affiliates — 157 43 — — 200 Short-term debt — — 841 — — 841 Deferred revenue — — 698 — — 698 Other current liabilities — 447 164 176 — 787 Total current liabilities — 832 9,009 426 — 10,267 Long-term debt — 10,950 1,174 — — 12,124 Long-term debt to affiliates — 14,582 — — — 14,582 Tower obligations (1) — — 384 2,173 — 2,557 Deferred tax liabilities — — 4,613 — (141) 4,472 Deferred rent expense — — 2,781 — — 2,781 Negative carrying value of subsidiaries, net — — 676 — (676) — Intercompany payables and debt 598 — 4,258 318 (5,174) — Other long-term liabilities — 20 926 21 — 967 Total long-term liabilities 598 25,552 14,812 2,512 (5,991) 37,483 Total stockholders' equity (deficit) 24,718 25,314 47,294 (1,454) (71,154) 24,718 Total liabilities and stockholders' equity $ 25,316 $ 51,698 $ 71,115 $ 1,484 $ (77,145) $ 72,468 (1) Assets and liabilities for Non-Guarantor Subsidiaries are primarily included in VIEs related to the 2012 Tower Transaction. See Note 9 – Tower Obligations for further information.
Schedule of Condensed Consolidating Statement of Comprehensive Income Information	Condensed Consolidating Statement of Comprehensive Income Information Year Ended December 31, 2019 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Revenues Service revenues $ — $ — $ 32,268 $ 3,003 $ (1,277) $ 33,994 Equipment revenues — — 10,053 3 (216) 9,840 Other revenues — 19 1,109 203 (167) 1,164 Total revenues — 19 43,430 3,209 (1,660) 44,998 Operating expenses Cost of services, exclusive of depreciation and amortization shown separately below — — 6,733 — (111) 6,622 Cost of equipment sales, exclusive of depreciation and amortization shown separately below — — 10,908 1,207 (216) 11,899 Selling, general and administrative — 16 14,467 989 (1,333) 14,139 Depreciation and amortization — — 6,564 52 — 6,616 Total operating expense — 16 38,672 2,248 (1,660) 39,276 Operating income — 3 4,758 961 — 5,722 Other income (expense) Interest expense — (454) (88) (185) — (727) Interest expense to affiliates — (409) (20) — 21 (408) Interest income — 22 20 3 (21) 24 Other (expense) income, net — (13) 6 (1) — (8) Total other expense, net — (854) (82) (183) — (1,119) Income (loss) before income taxes — (851) 4,676 778 — 4,603 Income tax expense — — (965) (170) — (1,135) Earnings of subsidiaries 3,468 4,319 31 — (7,818) — Net income $ 3,468 $ 3,468 $ 3,742 $ 608 $ (7,818) $ 3,468 Net income $ 3,468 $ 3,468 $ 3,742 $ 608 $ (7,818) $ 3,468 Other comprehensive (loss) income, net of tax Other comprehensive (loss) income, net of tax (536) (536) 186 — 350 (536) Total comprehensive income $ 2,932 $ 2,932 $ 3,928 $ 608 $ (7,468) $ 2,932 Condensed Consolidating Statement of Comprehensive Income Information Year Ended December 31, 2018 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Revenues Service revenues $ — $ — $ 30,637 $ 2,333 $ (978) $ 31,992 Equipment revenues — — 10,209 1 (201) 10,009 Other revenues — 29 1,113 228 (61) 1,309 Total revenues — 29 41,959 2,562 (1,240) 43,310 Operating expenses Cost of services, exclusive of depreciation and amortization shown separately below — — 6,283 24 — 6,307 Cost of equipment sales, exclusive of depreciation and amortization shown separately below — — 11,239 1,010 (202) 12,047 Selling, general and administrative — 11 13,296 892 (1,038) 13,161 Depreciation and amortization — — 6,422 64 — 6,486 Total operating expenses — 11 37,240 1,990 (1,240) 38,001 Operating income — 18 4,719 572 — 5,309 Other income (expense) Interest expense — (528) (114) (193) — (835) Interest expense to affiliates — (522) (21) — 21 (522) Interest income — 23 16 1 (21) 19 Other (expense) income, net — (87) 33 — — (54) Total other expense, net — (1,114) (86) (192) — (1,392) Income (loss) before income taxes — (1,096) 4,633 380 — 3,917 Income tax expense — — (950) (79) — (1,029) Earnings of subsidiaries 2,888 3,984 32 — (6,904) — Net income $ 2,888 $ 2,888 $ 3,715 $ 301 $ (6,904) $ 2,888 Net income $ 2,888 $ 2,888 $ 3,715 $ 301 $ (6,904) $ 2,888 Other comprehensive (loss) income, net of tax Other comprehensive (loss) income, net of tax (332) (332) 116 — 216 (332) Total comprehensive income $ 2,556 $ 2,556 $ 3,831 $ 301 $ (6,688) $ 2,556 Condensed Consolidating Statement of Comprehensive Income Information Year Ended December 31, 2017 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Revenues Service revenues $ — $ — $ 28,894 $ 2,113 $ (847) $ 30,160 Equipment revenues — — 9,620 — (245) 9,375 Other revenues — 3 879 212 (25) 1,069 Total revenues — 3 39,393 2,325 (1,117) 40,604 Operating expenses Cost of services, exclusive of depreciation and amortization shown separately below — — 6,076 24 — 6,100 Cost of equipment sales, exclusive of depreciation and amortization shown separately below — — 10,849 1,003 (244) 11,608 Selling, general and administrative — — 12,276 856 (873) 12,259 Depreciation and amortization — — 5,914 70 — 5,984 Gains on disposal of spectrum licenses — — (235) — — (235) Total operating expenses — — 34,880 1,953 (1,117) 35,716 Operating income — 3 4,513 372 — 4,888 Other income (expense) Interest expense — (811) (109) (191) — (1,111) Interest expense to affiliates — (560) (23) — 23 (560) Interest income 1 29 10 — (23) 17 Other income (expense), net — (88) 16 (1) — (73) Total other income (expense), net 1 (1,430) (106) (192) — (1,727) Income (loss) before income taxes 1 (1,427) 4,407 180 — 3,161 Income tax expense (benefit) — — 1,527 (152) — 1,375 Earnings (loss) of subsidiaries 4,535 5,962 (57) — (10,440) — Net income 4,536 4,535 5,877 28 (10,440) 4,536 Dividends on preferred stock (55) — — — — (55) Net income attributable to common stockholders $ 4,481 $ 4,535 $ 5,877 $ 28 $ (10,440) $ 4,481 Net income $ 4,536 $ 4,535 $ 5,877 $ 28 $ (10,440) $ 4,536 Other comprehensive loss, net of tax Other comprehensive loss, net of tax 7 7 7 — (14) 7 Total comprehensive income $ 4,543 $ 4,542 $ 5,884 $ 28 $ (10,454) $ 4,543
Schedule of Condensed Consolidating Statement of Cash Flows Information	Condensed Consolidating Statement of Cash Flows Information Year Ended December 31, 2019 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Operating activities Net cash (used in) provided by operating activities $ — $ (752) $ 11,338 $ (3,207) $ (555) $ 6,824 Investing activities Purchases of property and equipment — — (6,391) — — (6,391) Purchases of spectrum licenses and other intangible assets, including deposits — — (967) — — (967) Proceeds from sales of tower sites — — 38 — — 38 Proceeds related to beneficial interests in securitization transactions — — 37 3,839 — 3,876 Net cash related to derivative contracts under collateral exchange arrangements — (632) — — — (632) Acquisition of companies, net of cash acquired — (32) 1 — — (31) Other, net — (12) (6) — — (18) Net cash (used in) provided by investing activities — (676) (7,288) 3,839 — (4,125) Financing activities Proceeds from borrowing on revolving credit facility, net — 2,340 — — — 2,340 Repayments of revolving credit facility — — (2,340) — — (2,340) Repayments of financing lease obligations — — (798) — — (798) Repayments of short-term debt for purchases of inventory, property and equipment, net — — (775) — — (775) Repayments of long-term debt — — (600) — — (600) Intercompany advances, net 1 (912) 934 (23) — — Tax withholdings on share-based awards — — (156) — — (156) Cash payments for debt prepayment or debt extinguishment costs — — (28) — — (28) Intercompany dividend paid — — — (555) 555 — Other, net 2 — (19) — — (17) Net cash provided (used in) by financing activities 3 1,428 (3,782) (578) 555 (2,374) Change in cash and cash equivalents 3 — 268 54 — 325 Cash and cash equivalents Beginning of period 2 1 1,082 118 — 1,203 End of period $ 5 $ 1 $ 1,350 $ 172 $ — $ 1,528 Condensed Consolidating Statement of Cash Flows Information Year Ended December 31, 2018 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Operating activities Net cash (used in) provided by operating activities $ — $ (1,254) $ 10,414 $ (5,041) $ (220) $ 3,899 Investing activities Purchases of property and equipment — — (5,536) (5) — (5,541) Purchases of spectrum licenses and other intangible assets, including deposits — — (127) — — (127) Proceeds related to beneficial interests in securitization transactions — — 53 5,353 — 5,406 Acquisition of companies, net of cash — — (338) — — (338) Equity investment in subsidiary — — (43) — 43 — Other, net — (7) 28 — — 21 Net cash (used in) provided by investing activities — (7) (5,963) 5,348 43 (579) Financing activities Proceeds from issuance of long-term debt — 2,494 — — — 2,494 Proceeds from borrowing on revolving credit facility, net — 6,265 — — — 6,265 Repayments of revolving credit facility — — (6,265) — — (6,265) Repayments of financing lease obligations — — (700) — — (700) Repayments of short-term debt for purchases of inventory, property and equipment, net — — (300) — — (300) Repayments of long-term debt — — (3,349) — — (3,349) Repurchases of common stock (1,071) — — — — (1,071) Intercompany advances, net 995 (7,498) 6,530 (27) — — Equity investment from parent — — 43 — (43) — Tax withholdings on share-based awards — — (146) — — (146) Cash payments for debt prepayment or debt extinguishment costs — — (212) — — (212) Intercompany dividend paid — — — (220) 220 — Other, net 4 — (56) — — (52) Net cash (used in) provided by financing activities (72) 1,261 (4,455) (247) 177 (3,336) Change in cash and cash equivalents (72) — (4) 60 — (16) Cash and cash equivalents Beginning of period 74 1 1,086 58 — 1,219 End of period $ 2 $ 1 $ 1,082 $ 118 $ — $ 1,203 Condensed Consolidating Statement of Cash Flows Information Year Ended December 31, 2017 (in millions) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Consolidating and Eliminating Adjustments Consolidated Operating activities Net cash provided by (used in) operating activities $ 1 $ (1,613) $ 9,761 $ (4,218) $ (100) $ 3,831 Investing activities Purchases of property and equipment — — (5,237) — — (5,237) Purchases of spectrum licenses and other intangible assets, including deposits — — (5,828) — — (5,828) Proceeds related to beneficial interests in securitization transactions — — 43 4,276 — 4,319 Equity investment in subsidiary (308) — — — 308 — Other, net — — 1 — — 1 Net cash (used in) provided by investing activities (308) — (11,021) 4,276 308 (6,745) Financing activities Proceeds from issuance of long-term debt — 10,480 — — — 10,480 Proceeds from borrowing on revolving credit facility, net — 2,910 — — — 2,910 Repayments of revolving credit facility — — (2,910) — — (2,910) Repayments of financing lease obligations — — (486) — — (486) Repayments of short-term debt for purchases of inventory, property and equipment, net — — (300) — — (300) Repayments of long-term debt — — (10,230) — — (10,230) Repurchases of common stock (427) — — — — (427) Intercompany advances, net 484 (14,817) 14,300 33 — — Equity investment from parent — 308 — — (308) — Tax withholdings on share-based awards — — (166) — — (166) Dividends on preferred stock (55) — — — — (55) Cash payments for debt prepayment or debt extinguishment costs — — (188) — — (188) Intercompany dividend paid — — — (100) 100 — Other, net 21 — (16) — — 5 Net cash provided by (used in) financing activities 23 (1,119) 4 (67) (208) (1,367) Change in cash and cash equivalents (284) (2,732) (1,256) (9) — (4,281) Cash and cash equivalents Beginning of period 358 2,733 2,342 67 — 5,500 End of period $ 74 $ 1 $ 1,086 $ 58 $ — $ 1,219

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information [Abstract]
Quarterly Financial Information	Quarterly Financial Information (Unaudited) (in millions, except share and per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Full Year 2019 Total revenues $ 11,080 $ 10,979 $ 11,061 $ 11,878 $ 44,998 Operating income 1,476 1,541 1,471 1,234 5,722 Net income 908 939 870 751 3,468 Net income attributable to common stockholders 908 939 870 751 3,468 Earnings per share Basic $ 1.07 $ 1.10 $ 1.02 $ 0.88 $ 4.06 Diluted $ 1.06 $ 1.09 $ 1.01 $ 0.87 $ 4.02 Weighted average shares outstanding Basic 851,223,498 854,368,443 854,578,241 856,294,467 854,143,751 Diluted 858,643,481 860,135,593 862,690,751 864,158,739 863,433,511 2018 Total revenues $ 10,455 $ 10,571 $ 10,839 $ 11,445 $ 43,310 Operating income 1,282 1,450 1,440 1,137 5,309 Net income 671 782 795 640 2,888 Net income attributable to common stockholders 671 782 795 640 2,888 Earnings per share Basic $ 0.78 $ 0.92 $ 0.94 $ 0.75 $ 3.40 Diluted $ 0.78 $ 0.92 $ 0.93 $ 0.75 $ 3.36 Weighted average shares outstanding Basic 855,222,664 847,660,488 847,087,120 849,102,785 849,744,152 Diluted 862,244,084 852,040,670 853,852,764 856,344,347 858,290,174

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	Jan. 01, 2019USD ($)tower_site	Dec. 31, 2019USD ($)option	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)optionunit	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total imputed discount and allowance rate										7.00%	8.10%
Device upgrade period										18 months
Number of upgrade options | option		1								1
Spectrum license issuance period										15 years
Number of reporting units | unit										2
Federal Universal Service Fund and other fees										$ 93	$ 161	$ 258
Average amortization period, deferred contract costs (in months)		24 months								24 months
Advertising expense										$ 1,600	1,700	1,800
Operating leases		6 years								6 years
Total operating expense										$ 39,276	38,001	35,716
Revenues		$ 11,878	$ 11,061	$ 10,979	$ 11,080	$ 11,445	$ 10,839	$ 10,571	$ 10,455	44,998	43,310	40,604
Net income		751	$ 870	$ 939	$ 908	640	$ 795	$ 782	$ 671	3,468	2,888	4,536
Net cash provided by operating activities										6,824	3,899	3,831
Net cash (used in) provided by financing activities										(2,374)	(3,336)	(1,367)
Accumulated deficit	$ 12,301	8,833				$ 12,954				8,833	12,954
Tower Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property subject to failed sale leaseback transaction, number of units | tower_site	6,200
Other revenues
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues										1,164	$ 1,309	$ 1,069
CCI | Tower Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property subject to failed sale leaseback transaction, number of units | tower_site	900
PTI | Tower Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property subject to failed sale leaseback transaction, number of units | tower_site	500
CCI and PTI | Tower Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property subject to failed sale leaseback transaction, number of units | tower_site	1,400
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Average remaining lease term, operating lease	9 years
Operating leases	5 years
Accumulated deficit	$ (653)
Accounting Standards Update 2016-02 | Impact Excluding Failed Sale-Leaseback Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total operating expense										(240)
Accounting Standards Update 2016-02 | Tower Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest expense										(34)
Accounting Standards Update 2016-02 | Impact Including Failed Sale-Leaseback Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total operating expense										(380)
Net income										175
Net cash provided by operating activities										(10)
Net cash (used in) provided by financing activities										10
Accounting Standards Update 2016-02 | Other revenues | Tower Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues										(44)
Accounting Standards Update 2016-02 | Other revenues | Impact Including Failed Sale-Leaseback Transaction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues										(185)
Minimum | Accounting Standards Update 2016-13 | Pro Forma
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses		85								85
Deferred tax assets		(22)								(22)
Accumulated deficit		63								63
Maximum | Accounting Standards Update 2016-13 | Pro Forma
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses		95								95
Deferred tax assets		(25)								(25)
Accumulated deficit		$ 70								$ 70
EIP Securitization Arrangement | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equipment installment plan, maximum payment term										24 months
EIP Securitization Arrangement | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equipment installment plan, maximum payment term										36 months

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Cumulative Impact of Adoption (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Other current assets	$ 2,305	$ 1,598	$ 1,676
Property and equipment, net	21,984	21,020	23,359
Operating lease right-of-use assets	10,933	9,251
Financing lease right-of-use assets	2,715	2,271
Other intangible assets, net	115	186	198
Other assets	1,891	1,552	1,623
Liabilities and Stockholders' Equity
Accounts payable and accrued liabilities	6,746	7,676	7,741
Other current liabilities	1,673	815	787
Short-term and long-term debt		10,950	12,965
Tower obligations	2,236	2,212	2,557
Deferred tax liabilities	5,607	4,703	4,472
Deferred rent expense			2,781
Short-term and long-term operating lease liabilities	12,826	11,364
Short-term and long-term financing lease liabilities	2,303	2,016
Other long-term liabilities	954	903	967
Accumulated deficit	$ (8,833)	(12,301)	$ (12,954)
Accounting Standards Update 2016-02
Assets
Other current assets		(78)
Property and equipment, net		(2,339)
Operating lease right-of-use assets		9,251
Financing lease right-of-use assets		2,271
Other intangible assets, net		(12)
Other assets		(71)
Liabilities and Stockholders' Equity
Accounts payable and accrued liabilities		(65)
Other current liabilities		28
Short-term and long-term debt		(2,015)
Tower obligations		(345)
Deferred tax liabilities		231
Deferred rent expense		(2,781)
Short-term and long-term operating lease liabilities		11,364
Short-term and long-term financing lease liabilities		2,016
Other long-term liabilities		(64)
Accumulated deficit		$ 653

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($)	Jul. 26, 2019	May 18, 2018	Apr. 29, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018
DISH | T-Mobile and Sprint | Prepaid Business
Business Acquisition [Line Items]
Payments for asset acquisition	$ 1,400,000,000
DISH | T-Mobile and Sprint | Prepaid Business | Transition Services Agreement
Business Acquisition [Line Items]
Transition period (up to)	3 years
DISH | T-Mobile and Sprint | Prepaid Business | Master Network Services Agreement
Business Acquisition [Line Items]
Transition period (up to)	7 years
DISH | T-Mobile and Sprint | Spectrum Licenses
Business Acquisition [Line Items]
Payments for asset acquisition	$ 3,600,000,000
Additional lease period	2 years
T-Mobile and Sprint | DISH | Decommissioned Towers and Retail Locations
Business Acquisition [Line Items]
Option period (up to)	5 years
Sprint
Business Acquisition [Line Items]
Exchange ratio (in shares)			0.10256
Exchange ratio (in shares)			9.75
Fully-diluted shares of combined company held by public stockholders (percent)					31.30%
Required fees by acquirer upon consummation					$ 0
Required reimbursement by acquiree upon termination, percentage		33.00%
Required reimbursement of consent, bank, and other fees paid or accrued					18,000,000
Accrued required reimbursement by acquiree upon termination					0
Required reimbursement by acquirer upon termination, percentage		67.00%
Required reimbursement by acquirer upon termination					162,000,000
Accrued required reimbursement by acquirer upon termination					0
Costs recognized associated with merger transaction					620,000,000	$ 196,000,000
Payments for Merger-related costs					442,000,000	86,000,000
Required payment resulting from failure to satisfy closing condition of business combination agreement (up to)			$ 600,000,000
Sprint | Deutsche Telekom AG
Business Acquisition [Line Items]
Payments for requisite consents to DT			$ 13,000,000
Payments of consent fees				$ 7,000,000
Sprint | Senior Notes
Business Acquisition [Line Items]
Payments for requisite consents to third-party note holders		$ 95,000,000		$ 54,000,000
Payments of consent fees					$ 242,000,000
Sprint | Deutsche Telekom AG
Business Acquisition [Line Items]
Fully-diluted shares expected to be held immediately following merger (percent)					41.50%
Required fees by acquirer upon consummation					$ 0	$ 0
Sprint | SoftBank
Business Acquisition [Line Items]
Fully-diluted shares expected to be held immediately following merger (percent)					27.20%

Receivables and Allowance for_3

Receivables and Allowance for Credit Losses - EIP Receivables (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)classsegment	Dec. 31, 2018USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio segments | segment	2
Customer classes | class	2
EIP receivables, gross	$ 4,582	$ 4,534
Unamortized imputed discount	(299)	(330)
EIP receivables, net of unamortized imputed discount	4,283	4,204
Allowance for credit losses	(100)	(119)
Equipment installment plan receivables, net	4,183	4,085
Equipment installment plan receivables, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment installment plan receivables, net	2,600	2,538
Equipment installment plan receivables due after one year, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment installment plan receivables, net	$ 1,583	$ 1,547

Receivables and Allowance for_4

Receivables and Allowance for Credit Losses - Unamortized Imputed Discount and Allowance for Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses and imputed discount, beginning of period	$ 516	$ 516	$ 482	$ 418
Bad debt expense		307	297	388
Write-offs, net of recoveries		(332)	(328)	(393)
Change in imputed discount on short-term and long-term EIP receivables		136	250	252
Impact on the imputed discount from sales of EIP receivables		(167)	(185)	(183)
Allowance for credit losses and imputed discount, end of period		460	516	482
Accounts Receivable Allowance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses and imputed discount, beginning of period	$ 67	67	86	102
Bad debt expense		77	69	104
Write-offs, net of recoveries		(83)	(88)	(120)
Allowance for credit losses and imputed discount, end of period		$ 61	67	86
EIP Receivables Allowance
Financing Receivable, Allowance for Credit Loss [Line Items]
Weighted average effective imputed interest rate (percentage)	10.00%	8.80%
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses and imputed discount, beginning of period	$ 449	$ 449	396	316
Bad debt expense		230	228	284
Write-offs, net of recoveries		(249)	(240)	(273)
Change in imputed discount on short-term and long-term EIP receivables		136	250	252
Impact on the imputed discount from sales of EIP receivables		(167)	(185)	(183)
Allowance for credit losses and imputed discount, end of period		$ 399	$ 449	$ 396

Receivables and Allowance for_5

Receivables and Allowance for Credit Losses - Gross EIP Receivables by Credit Category (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	$ 4,582	$ 4,534
Prime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	2,411	2,015
Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	2,171	2,519
Current - 30 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	4,492	4,433
Current - 30 days past due | Prime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	2,384	1,987
Current - 30 days past due | Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	2,108	2,446
31 - 60 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	41	47
31 - 60 days past due | Prime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	13	15
31 - 60 days past due | Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	28	32
61 - 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	24	25
61 - 90 days past due | Prime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	7	6
61 - 90 days past due | Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	17	19
More than 90 days past due
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	25	29
More than 90 days past due | Prime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	7	7
More than 90 days past due | Subprime
Financing Receivable, Credit Quality Indicator [Line Items]
EIP receivables, gross	$ 18	$ 22

Sales of Certain Receivables -

Sales of Certain Receivables - Sales of Service Receivables (Details) - USD ($)	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2014
Variable Interest Entity [Line Items]
Other current assets	$ 2,305,000,000	$ 1,598,000,000	$ 1,676,000,000
Accounts payable and accrued liabilities	6,746,000,000	7,676,000,000	7,741,000,000
Other current liabilities	1,673,000,000	$ 815,000,000	787,000,000
Factoring Arrangement | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Revolving receivables facility, maximum borrowing capacity				$ 950,000,000
Revolving receivables facility, outstanding borrowings	924,000,000		774,000,000
Other current assets	350,000,000		339,000,000
Accounts payable and accrued liabilities	25,000,000		59,000,000
Other current liabilities	$ 342,000,000		$ 149,000,000

Sales of Certain Receivables _2

Sales of Certain Receivables - Sales of EIP Receivables (Details) - USD ($)	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2015
Variable Interest Entity [Line Items]
Other current assets	$ 2,305,000,000	$ 1,598,000,000	$ 1,676,000,000
Other assets	1,891,000,000	$ 1,552,000,000	1,623,000,000
EIP Securitization Arrangement
Variable Interest Entity [Line Items]
Revolving receivables facility, maximum borrowing capacity	1,300,000,000		1,300,000,000	$ 1,300,000,000
Other current assets	344,000,000		321,000,000
Other assets	89,000,000		88,000,000
Other long-term liabilities	$ 18,000,000		$ 22,000,000

Sales of Certain Receivables _3

Sales of Certain Receivables - Sales of Receivables and Continuing Involvement (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Other current assets	$ 2,305	$ 1,676		$ 1,598
Other long-term assets	1,891	1,623		1,552
Accounts payable and accrued liabilities	6,746	7,741		7,676
Other current liabilities	1,673	787		815
Other long-term liabilities	954	967		$ 903
Of which:
Losses from sales of receivables	130	157	$ 299
Factoring and EIP Securitization Arrangement | Variable Interest Entity, Primary Beneficiary
Of which:
Maximum exposure to loss, Factoring VIE	1,100
Factoring and EIP Securitization Arrangement | Variable Interest Entity, Primary Beneficiary
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Derecognized net service receivables and EIP receivables	2,584	2,577
Other current assets	694	660
Deferred purchase price assets	781	746
Other long-term assets	89	88
Accounts payable and accrued liabilities	25	59
Other current liabilities	342	149
Other long-term liabilities	18	22
Net cash proceeds since inception	1,944	1,879
Of which:
Change in net cash proceeds during the year-to-date period	65	(179)
Net cash proceeds funded by reinvested collections	1,879	2,058
Losses from sales of receivables	130	157	$ 299
Factoring and EIP Securitization Arrangement | Other current assets - of which, deferred purchase price | Variable Interest Entity, Primary Beneficiary
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Deferred purchase price assets	692	658
Factoring and EIP Securitization Arrangement | Other long-term assets - of which, deferred purchase price | Variable Interest Entity, Primary Beneficiary
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Deferred purchase price assets	$ 89	$ 88

Property and Equipment (Details

Property and Equipment (Details) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2019USD ($)tower_site	Dec. 31, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jan. 01, 2019USD ($)
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ (33,118)	$ (33,118)	$ (33,118)	$ (31,297)
Property and equipment, net	$ 21,984	21,984	21,984	23,359		$ 21,020
Capitalized interest			473	362	$ 136
Number of wireless communications tower sites sold | tower_site	168
Proceeds from sales of tower sites	$ 38		$ 38	0	0
Gain recognized as a reduction in Cost of services, exclusive of depreciation and amortization		13
Initial term of space leased out			10 years
Depreciation expense			$ 6,000	6,400	5,800
Depreciation expense for lease devices			543	940	$ 1,000
Buildings and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment	2,587	2,587	2,587	2,428
Wireless communications systems
Property, Plant and Equipment [Line Items]
Property, plant and equipment	34,353	34,353	34,353	35,282
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,345	1,345	1,345	1,299
Capitalized software
Property, Plant and Equipment [Line Items]
Property, plant and equipment	12,705	12,705	12,705	11,712
Leased wireless devices
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,139	1,139	1,139	1,159
Accumulated depreciation and amortization	(407)	(407)	(407)
Property and equipment, net	732	732	732
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 2,973	$ 2,973	$ 2,973	$ 2,776
Maximum | Buildings and equipment
Property, Plant and Equipment [Line Items]
Useful life (in years)			40 years
Maximum | Wireless communications systems
Property, Plant and Equipment [Line Items]
Useful life (in years)			20 years
Maximum | Leasehold improvements
Property, Plant and Equipment [Line Items]
Useful life (in years)			12 years
Maximum | Capitalized software
Property, Plant and Equipment [Line Items]
Useful life (in years)			10 years
Maximum | Leased wireless devices
Property, Plant and Equipment [Line Items]
Useful life (in years)			18 months

Property and Equipment - Asset

Property and Equipment - Asset Retirement Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations, beginning of year	$ 609	$ 562
Liabilities incurred	35	26
Liabilities settled	(2)	(9)
Accretion expense	32	30
Changes in estimated cash flows	(15)	0
Asset retirement obligations, end of year	659	609
Asset retirement costs capitalized, net	159	194
Other long-term liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Asset retirement obligations, beginning of year	609
Asset retirement obligations, end of year	$ 659	$ 609

Goodwill, Spectrum License Tr_3

Goodwill, Spectrum License Transactions and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Historical goodwill		$ 12,449
Goodwill from acquisition	$ 29
Accumulated impairment losses	(10,766)	(10,766)
December 31, 2018	1,901
December 31, 2019	$ 1,930	1,901
Layer3 TV
Goodwill [Roll Forward]
Goodwill from acquisition		$ 218

Goodwill, Spectrum License Tr_4

Goodwill, Spectrum License Transactions and Other Intangible Assets - Narrative (Details) - USD ($) $ in Millions	1 Months Ended
	Jul. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill		$ 1,930	$ 1,901
PushSpring
Goodwill [Line Items]
Cash consideration	$ 32
Goodwill	$ 29

Goodwill, Spectrum License Tr_5

Goodwill, Spectrum License Transactions and Other Intangible Assets - Spectrum Licenses (Details) $ in Millions	1 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)license	Feb. 28, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Oct. 31, 2018USD ($)
Indefinite-lived Intangible Assets [Roll Forward]
Purchase of spectrum licenses			$ 967	$ 127	$ 5,828
Iowa Wireless
Indefinite-lived Intangible Assets [Roll Forward]
Spectrum licenses				87
Licensing Agreements
Indefinite-lived Intangible Assets [Roll Forward]
Beginning balance			35,559	35,366
Spectrum license acquisitions			857	138
Spectrum licenses transferred to held for sale			0	(1)
Costs to clear spectrum			49	56
Ending balance			$ 36,465	35,559	$ 35,366
Number of licenses | license	2,211
Purchase of spectrum licenses	$ 842			$ 50
Licensing Agreements | 28 GHz Auction
Indefinite-lived Intangible Assets [Roll Forward]
Purchase of spectrum licenses		$ 19
Asset purchase deposit						$ 20
Licensing Agreements | 24 GHz Auction
Indefinite-lived Intangible Assets [Roll Forward]
Purchase of spectrum licenses	$ 656
Asset purchase deposit		$ 147

Goodwill, Spectrum License Tr_6

Goodwill, Spectrum License Transactions and Other Intangible Assets - Other Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment	$ 0	$ 0
Indefinite-lived intangible asset impairment	0	0
Finite-Lived Intangible Assets, Gross	1,527,000,000	1,565,000,000
Finite-Lived Intangible Assets, Accumulated Amortization	(1,412,000,000)	(1,367,000,000)
Net Amount	115,000,000	198,000,000		$ 186,000,000
Amortization expense for intangible assets	82,000,000	124,000,000	$ 163,000,000
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2020	83,000,000
2021	14,000,000
2022	3,000,000
2023	3,000,000
2024	3,000,000
Thereafter	9,000,000
Net Amount	115,000,000	198,000,000		$ 186,000,000
Customer lists
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	1,104,000,000	1,104,000,000
Finite-Lived Intangible Assets, Accumulated Amortization	(1,104,000,000)	(1,086,000,000)
Net Amount	0	18,000,000
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Net Amount	$ 0	18,000,000
Customer lists | Maximum
Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life (in years)	6 years
Trademarks and patents
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 323,000,000	312,000,000
Finite-Lived Intangible Assets, Accumulated Amortization	(258,000,000)	(225,000,000)
Net Amount	65,000,000	87,000,000
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Net Amount	$ 65,000,000	87,000,000
Trademarks and patents | Maximum
Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life (in years)	19 years
Other
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 100,000,000	149,000,000
Finite-Lived Intangible Assets, Accumulated Amortization	(50,000,000)	(56,000,000)
Net Amount	50,000,000	93,000,000
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
Net Amount	$ 50,000,000	$ 93,000,000
Other | Maximum
Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life (in years)	28 years

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Apr. 29, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 28, 2019	Oct. 31, 2018
Derivative [Line Items]
Accumulated other comprehensive loss		$ 868	$ 868	$ 332
Net collateral transfers to certain derivative counterparties		(632)	632	0	$ 0
Gain on embedded derivatives	$ 11		8	29	$ 52
Fair value of embedded derivative				19
Guarantee liabilities		62	62	73
EIP receivables, gross		4,582	4,582	4,534
Equipment installment plan receivables, net
Derivative [Line Items]
EIP receivables, gross		3,000	3,000
Affiliated Entity | 9.332% Senior Reset Notes to affiliates due 2023
Derivative [Line Items]
Interest rate, stated percentage						9.332%
Redemption price (as a percent)	104.666%
Interest Rate Contract | Cash Flow Hedging
Derivative [Line Items]
Aggregate notional amount							$ 9,600
Fair value of derivative instrument		$ 1,200	$ 1,200	$ 447

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Short-term Investments and Long-term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Level 3 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred purchase price assets	$ 781	$ 746
Level 3 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred purchase price assets	781	746
Level 1 | Carrying Amount | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	10,958	10,950
Level 1 | Fair Value | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	11,479	10,945
Level 2 | Carrying Amount | Secured Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Term loans	4,000	4,000
Level 2 | Carrying Amount | Affiliated Entity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	598
Level 2 | Carrying Amount | Senior Notes | Affiliated Entity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	9,986	9,984
Level 2 | Fair Value | Secured Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Term loans	4,000	3,976
Level 2 | Fair Value | Affiliated Entity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	0	640
Level 2 | Fair Value | Senior Notes | Affiliated Entity
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 10,366	$ 9,802

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2019	Apr. 28, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Capital leases			$ 2,015
Financing arrangements for property and equipment	$ 25
Debt issuance costs and consent fees	(46)		(56)
Total debt	24,969		27,547
Less: Current portion of capital leases			841
Less: Financing arrangements for property and equipment	25
Total long-term debt	24,944		26,706
Long-term debt	10,958		12,124
Long-term debt to affiliates	13,986		14,582
Affiliated Entity
Debt Instrument [Line Items]
Unamortized premium on debt to affiliates	43		52
Unamortized discount on Senior Notes to affiliates	(53)		(64)
Long-term debt to affiliates	$ 13,986		14,582
5.300% Senior Notes to affiliates due 2021 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	530.00%
Due to affiliates	$ 2,000		2,000
4.000% Senior Notes due 2022 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	400.00%
Senior notes	$ 500		500
4.000% Senior Notes due 2022 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	400.00%
Due to affiliates	$ 1,000		1,000
Incremental term loan facility to affiliates due 2022 | Affiliated Entity
Debt Instrument [Line Items]
Due to affiliates	$ 2,000		2,000
6.000% Senior Notes due 2023 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	600.00%
Senior notes	$ 1,300		1,300
9.332% Senior Reset Notes to affiliates due 2023 | Affiliated Entity
Debt Instrument [Line Items]
Interest rate, stated percentage		9.332%
9.332% Senior Reset Notes to affiliates due 2023 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	933.20%
Due to affiliates	$ 0		600
6.000% Senior Notes due 2024 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	600.00%
Senior notes	$ 1,000		1,000
6.500% Senior Notes due 2024 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	650.00%
Senior notes	$ 1,000		1,000
6.000% Senior Notes to affiliates due 2024 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	600.00%
Due to affiliates	$ 1,350		1,350
6.000% Senior Notes to affiliates due 2024 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	600.00%
Due to affiliates	$ 650		650
Incremental term loan facility to affiliates due 2024 | Affiliated Entity
Debt Instrument [Line Items]
Due to affiliates	$ 2,000		2,000
5.125% Senior Notes Due 2025 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	512.50%
Senior notes	$ 500		500
5.125% Senior Notes Due 2025 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	512.50%
Due to affiliates	$ 1,250		1,250
6.375% Senior Notes due 2025 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	637.50%
Senior notes	$ 1,700		1,700
6.500% Senior Notes due 2026 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	650.00%
Senior notes	$ 2,000		2,000
4.500% Senior Notes due 2026 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	450.00%
Senior notes	$ 1,000		1,000
4.500% Senior Notes due 2026 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	450.00%
Due to affiliates	$ 1,000		1,000
5.375% Senior Notes Due 2027 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	537.50%
Senior notes	$ 500		500
5.375% Senior Notes Due 2027 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	537.50%
Due to affiliates	$ 1,250		1,250
4.750% Senior Notes due 2028 | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	475.00%
Senior notes	$ 1,500		1,500
4.750% Senior Notes due 2028 | Affiliated Entity | Senior Notes
Debt Instrument [Line Items]
Interest rate, stated percentage	475.00%
Due to affiliates	$ 1,500		$ 1,500

Debt - Debt to Affiliates - Not

Debt - Debt to Affiliates - Notes Redemption (Details) - Affiliated Entity - Senior Notes - 9.332% Senior Notes due 2023 $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Interest rate, stated percentage	9.332%
Principal Amount	$ 600
Write-off of Embedded Derivatives	11
Other	$ 28
Redemption price (as a percent)	104.666%

Debt - Debt to Affiliates - Inc

Debt - Debt to Affiliates - Incremental Term Loan Facility (Details) - Deutsche Telekom AG - Affiliated Entity - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Short-term Debt [Line Items]
Issuance fees	$ 0	$ 0
LIBOR plus 1.50% Senior Secured Term Loan due 2022
Short-term Debt [Line Items]
Applicable margin, percentage			1.50%
Senior Secured Term Loans			$ 2,000,000,000
LIBOR plus 1.75% Senior Secured Term Loan due 2024
Short-term Debt [Line Items]
Applicable margin, percentage			1.75%
Senior Secured Term Loans			$ 2,000,000,000

Debt - Debt to Affiliates - Com

Debt - Debt to Affiliates - Commitment Letter (Details) - Sprint - USD ($)	Sep. 06, 2019	Dec. 31, 2019	Sep. 07, 2019
Debt Instrument [Line Items]
Required fees by acquirer upon consummation		$ 0
Secured and Unsecured Debt Financing
Debt Instrument [Line Items]
Financing commitment, amount	$ 30,000,000,000
Secured and Unsecured Debt Financing | Scenario One
Debt Instrument [Line Items]
Payments of consent fees	340,000,000
Required fees by acquirer upon consummation		$ 12,000,000
Secured Revolving Credit Facility
Debt Instrument [Line Items]
Financing commitment, amount	4,000,000,000
Secured Term Loan Facility
Debt Instrument [Line Items]
Financing commitment, amount	7,000,000,000		$ 4,000,000,000
Secured Bridge Loan Facility
Debt Instrument [Line Items]
Financing commitment, amount	$ 19,000,000,000

Debt - Debt to Affiliates - Fin

Debt - Debt to Affiliates - Financing Matters Agreement and Consents on Debt to Third-Parties (Details) - USD ($)	May 18, 2018	Apr. 29, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Payments for third party bank fees				$ 14,139,000,000	$ 13,161,000,000	$ 12,259,000,000
Senior Notes | 5.125% Senior Notes Due 2025
Debt Instrument [Line Items]
Interest rate, stated percentage				512.50%
Senior Notes | 5.375% Senior Notes Due 2027
Debt Instrument [Line Items]
Interest rate, stated percentage				537.50%
Sprint
Debt Instrument [Line Items]
Required fees by acquirer upon consummation				$ 0
Notes issued and outstanding under Existing Sprint Spectrum Program (not exceed)	$ 7,000,000,000
Sprint | Credit Facilities
Debt Instrument [Line Items]
Financing commitment, amount	$ 9,000,000,000
Secured indebtedness, limit, percentage	150.00%
Secured debt to cash flow	2
Sprint | Senior Notes
Debt Instrument [Line Items]
Payments of consent fees				$ 242,000,000
Payments for third party bank fees			$ 6,000,000
Payments for requisite consents to third-party note holders	$ 95,000,000		54,000,000
Sprint | Senior Notes | Long-term debt
Debt Instrument [Line Items]
Payments of consent fees			17,000,000
Sprint | Senior Notes | Existing Sprint Spectrum Notes
Debt Instrument [Line Items]
Payments for requisite consents to third-party note holders			41,000,000
Sprint | Senior Notes | Existing Sprint Spectrum Notes | Long-term debt
Debt Instrument [Line Items]
Payments of consent fees			14,000,000
Sprint | Deutsche Telekom AG
Debt Instrument [Line Items]
Payments of consent fees			$ 7,000,000
Payments for requisite consents to DT		$ 13,000,000
Sprint | Deutsche Telekom AG | Senior Notes | 5.300% Senior Notes to affiliates due 2021
Debt Instrument [Line Items]
Repayment of debt		$ 2,000,000,000
Interest rate, stated percentage		5.30%
Sprint | Deutsche Telekom AG | Senior Notes | 6.000% Senior Notes due 2024
Debt Instrument [Line Items]
Repayment of debt		$ 2,000,000,000
Interest rate, stated percentage		6.00%
Sprint | Deutsche Telekom AG | Senior Notes | 5.125% Senior Notes Due 2025
Debt Instrument [Line Items]
Interest rate, stated percentage		5.125%
Debt instrument, face amount		$ 1,250,000,000
Sprint | Deutsche Telekom AG | Senior Notes | 5.375% Senior Notes Due 2027
Debt Instrument [Line Items]
Interest rate, stated percentage		5.375%
Debt instrument, face amount		$ 1,250,000,000

Debt - Financing Arrangements a

Debt - Financing Arrangements and Revolving Credit Facility (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Short-term debt	$ 25,000,000
Issuance of short-term debt	2,340,000,000	$ 6,265,000,000	$ 2,910,000,000
Repayments of vendor financing arrangements	775,000,000	300,000,000	$ 300,000,000
Revolving Credit Facility [$2.5B] | Affiliated Entity
Debt Instrument [Line Items]
Revolving credit facility	2,500,000,000
Revolving Credit Facility [$2.5B] | Unsecured Revolving Credit Facility | Affiliated Entity
Debt Instrument [Line Items]
Revolving credit facility	1,000,000,000
Line of Credit | Revolving Credit Facility [$2.5B] | Secured Revolving Credit Facility | Affiliated Entity | Deutsche Telekom AG
Debt Instrument [Line Items]
Outstanding borrowings	0	0
Line of Credit | Revolving Credit Facility [$1.5B] | Secured Revolving Credit Facility | Affiliated Entity | Deutsche Telekom AG
Debt Instrument [Line Items]
Financing commitment, amount	1,500,000,000
Handset Financing Arrangement
Debt Instrument [Line Items]
Borrowing capacity	108,000,000
Short-term debt	0	0
Vendor Financing Arrangement
Debt Instrument [Line Items]
Short-term debt		$ 0
Issuance of short-term debt	800,000,000
Repayments of vendor financing arrangements	$ 775,000,000

Debt - Standby Letters of Credi

Debt - Standby Letters of Credit (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Letters of credit, amount outstanding	$ 113	$ 86
JP Morgan Chase
Debt Instrument [Line Items]
Letters of credit, amount outstanding	20	20
Deutsche Bank
Debt Instrument [Line Items]
Letters of credit, amount outstanding	$ 93	$ 66

Tower Obligations - Narrative (

Tower Obligations - Narrative (Details) $ in Millions	Jan. 01, 2019tower_site	Dec. 31, 2019tower_site	Dec. 31, 2015USD ($)tower_site	Dec. 31, 2012USD ($)tower_site	Dec. 31, 2018
Sale Leaseback Transaction [Line Items]
Number of wireless communications tower sites sold		168
Minimum
Sale Leaseback Transaction [Line Items]
Lessee leasing arrangements, operating leases, term of contract (years)		5 years			5 years
Maximum
Sale Leaseback Transaction [Line Items]
Lessee leasing arrangements, operating leases, term of contract (years)		10 years			10 years
Tower Transaction
Sale Leaseback Transaction [Line Items]
Number of wireless communications tower sites sold				7,100
Net proceeds, financing activities | $				$ 2,500
Property subject to failed sale leaseback transaction, number of units	6,200
Lessee leasing arrangements, operating leases, term of contract (years)			10 years	10 years
Sale leaseback transaction, fixed-price purchase options | $				$ 2,000
Sale Leaseback, Interest Rate				8.00%
Tower Transaction | Minimum
Sale Leaseback Transaction [Line Items]
Lessee leasing arrangements, operating leases, term of contract (years)				23 years
Tower Transaction | Maximum
Sale Leaseback Transaction [Line Items]
Lessee leasing arrangements, operating leases, term of contract (years)				37 years
Tower Transaction PTI
Sale Leaseback Transaction [Line Items]
Net proceeds, financing activities | $			$ 140
Property subject to failed sale leaseback transaction, number of units			150
Sale Leaseback, Interest Rate			5.00%

Tower Obligations - Sale Leaseb

Tower Obligations - Sale Leaseback Transaction (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Sale Leaseback Transaction [Line Items]
Failed sale-leasebacks	$ 198	$ 329
Failed Sale Leaseback Transaction, Tower Obligations
Sale Leaseback Transaction [Line Items]
Failed sale-leasebacks	$ 2,236	$ 2,557

Tower Obligations - Future Mini

Tower Obligations - Future Minimum Payments (Details) $ in Millions	Dec. 31, 2019USD ($)
Leases [Abstract]
Tower obligation payments, due 2020	$ 160
Tower obligation payments, due 2021 and 2022	321
Tower obligation payment, due 2023 and 2024	320
Tower obligation payments due thereafter	$ 467

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 11,878	$ 11,061	$ 10,979	$ 11,080	$ 11,445	$ 10,839	$ 10,571	$ 10,455	$ 44,998	$ 43,310	$ 40,604
Branded postpaid phone revenues
Disaggregation of Revenue [Line Items]
Revenues									21,329	19,745	18,371
Branded postpaid other revenues
Disaggregation of Revenue [Line Items]
Revenues									1,344	1,117	1,077
Branded postpaid service revenues
Disaggregation of Revenue [Line Items]
Revenues									22,673	20,862	19,448
Equipment revenues from the lease of mobile communication devices
Disaggregation of Revenue [Line Items]
Revenues									$ 599	$ 692	$ 877

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Balances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change in Contract with Customer, Asset and Liability [Abstract]
Contract Assets	$ 63	$ 51
Contract Liabilities	560	645
Change in contract assets included in other current assets	12
Change in contracts liabilities included in deferred revenue	(85)
Current portion of contract assets	50	51
Amounts included in the beginning of year contract liability balance	$ 643	$ 710

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Remaining Performance Obligations, Branded Postpaid Contracts (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Branded postpaid service revenues
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 237
Remaining contract duration (in years)	24 months
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining contract duration (in years)	1 year
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining contract duration (in years)	10 years

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Remaining Performance Obligations (Details) $ in Millions	Dec. 31, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1,300
Remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 894
Remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 791
Remaining performance obligation, expected timing of satisfaction, period

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Contract Costs (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Capitalized Contract Cost [Abstract]
Deferred incremental costs to obtain contracts	$ 906,000,000	$ 644,000,000
Average amortization period, deferred contract costs (in months)	24 months
Amortization of deferred costs	$ 604,000,000	267,000,000
Impairment losses recognized on deferred contract cost assets	$ 0	$ 0

Employee Compensation and Ben_3

Employee Compensation and Benefit Plans - Narrative (Details)	12 Months Ended
	Dec. 31, 2019shares
Restricted Stock and Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Performance Restricted Stock Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
2013 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance (in shares)	82,000,000
Number of shares available for future grants (in shares)	19,000,000

Employee Compensation and Ben_4

Employee Compensation and Benefit Plans - Schedule of Stock-based Compensation Expense and Related Income Tax Benefits (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 495	$ 424	$ 306
Income tax benefit related to stock-based compensation	$ 92	$ 81	$ 73
Restricted Stock Units and Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value per stock award granted (in USD per share)	$ 73.25	$ 61.52	$ 60.21
Unrecognized compensation expense	$ 515	$ 547	$ 445
Weighted average period to be recognized (years)	1 year 7 months 6 days	1 year 9 months 18 days	1 year 10 months 24 days
Fair value of stock awards vested	$ 512	$ 471	$ 503

Employee Compensation and Ben_5

Employee Compensation and Benefit Plans - Schedule of Restricted Stock and Unit Awards and Performance Restricted Stock Units Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Aggregate Intrinsic Value
Taxes paid related to net share settlement of stock awards	$ 156	$ 146	$ 166
Minimum
Aggregate Intrinsic Value
Share payout percentage	0.00%
Maximum
Aggregate Intrinsic Value
Share payout percentage	200.00%
Restricted Stock and Unit Awards
Number of Units or Awards
Nonvested, beginning (in shares)	11,010,635
Granted (in shares)	6,099,719
Vested (in shares)	(5,862,128)
Forfeited (in shares)	(745,015)
Nonvested, ending (in shares)	10,503,211	11,010,635
Weighted Average Grant Date Fair Value
Nonvested, beginning (in USD per share)	$ 57.66
Granted (in USD per share)	73.13
Vested (in USD per share)	55.52
Forfeited (in USD per share)	65.87
Nonvested, ending (in USD per share)	$ 67.31	$ 57.66
Weighted Average Remaining Contractual Term (Years)
Nonvested, Weighted Average Remaining Contractual Term, beginning (in years)	10 months 24 days	1 year
Nonvested, Weighted Average Remaining Contractual Term, ending (in years)	10 months 24 days	1 year
Aggregate Intrinsic Value
Nonvested, Aggregate Intrinsic Value, beginning	$ 824	$ 700
Nonvested, Aggregate Intrinsic Value, ending	$ 824	$ 700
Performance Restricted Stock Units
Number of Units or Awards
Nonvested, beginning (in shares)	3,851,554
Granted (in shares)	1,046,792
Vested (in shares)	(1,006,404)
Forfeited (in shares)	(88,403)
Nonvested, ending (in shares)	3,803,539	3,851,554
Weighted Average Grant Date Fair Value
Nonvested, beginning (in USD per share)	$ 64.03
Granted (in USD per share)	73.98
Vested (in USD per share)	52.47
Forfeited (in USD per share)	62.02
Nonvested, ending (in USD per share)	$ 69.78	$ 64.03
Weighted Average Remaining Contractual Term (Years)
Nonvested, Weighted Average Remaining Contractual Term, beginning (in years)	1 year	1 year 7 months 6 days
Nonvested, Weighted Average Remaining Contractual Term, ending (in years)	1 year	1 year 7 months 6 days
Aggregate Intrinsic Value
Nonvested, Aggregate Intrinsic Value, beginning	$ 300	$ 245
Nonvested, Aggregate Intrinsic Value, ending	$ 300	$ 245
Restricted Stock Units and Performance Stock Units
Weighted Average Grant Date Fair Value
Granted (in USD per share)	$ 73.25	$ 61.52	$ 60.21
Aggregate Intrinsic Value
Shares paid for tax withholding for share based compensation (in shares)	2,094,555	2,321,827

Employee Compensation and Ben_6

Employee Compensation and Benefit Plans - Employee Stock Purchase Plan (Details) - shares	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Contribution percentage (up to)		15.00%
Stock purchase discount percentage		15.00%
ESPP, offering period		6 months
Number of securities remaining available for future sale and issuance under ESPP (in shares)		1,397,894
Aggregate number of shares, annual increase (in shares)		5,000,000
Subsequent Event
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Additional shares of common stock (in shares)	5,000,000
Common Stock
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Number of shares issued under ESPP (in shares)		2,091,650	2,011,794	1,832,043

Employee Compensation and Ben_7

Employee Compensation and Benefit Plans - Stock Options (Details) - Predecessor Plans - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding and exercisable, beginning (in shares)	284,811
Exercised (in shares)	(85,083)
Expired/canceled (in shares)	(4,786)
Outstanding and exercisable, ending (in shares)	194,942	284,811
Exercisable (in shares)	180,966
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding and exercisable, beginning (usd per share)	$ 14.58
Exercised (usd per share)	15.94
Expired/canceled (usd per share)	22.75
Outstanding and exercisable, ending (usd per share)	13.80	$ 14.58
Exercisable (usd per share)	$ 13.48
Weighted Average Remaining Contractual Term (Years), Outstanding	2 years 10 months 24 days	3 years 9 months 18 days
Weighted Average Remaining Contractual Term (Years), Exercisable	2 years 7 months 6 days
Proceeds from exercise of stock options	$ 1	$ 3

Employee Compensation and Ben_8

Employee Compensation and Benefit Plans - Employee Retirement Savings Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement [Abstract]
Employer retirement savings plan, matching contributions	$ 119	$ 102	$ 87

Repurchases of Common Stock - N

Repurchases of Common Stock - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended	21 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2019	Apr. 27, 2018	Dec. 06, 2017
Affiliated Entity | Deutsche Telekom AG
Equity, Class of Treasury Stock [Line Items]
Additional shares purchased (in shares)	3,300,000	0	0
Aggregate market value of shares purchased	$ 200,000,000
2017 Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount				$ 9,000,000,000	$ 1,500,000,000
2018 Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, increase in authorized amount				$ 7,500,000,000

Repurchases of Common Stock - S

Repurchases of Common Stock - Schedule of Repurchases of Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	5 Months Ended	12 Months Ended
	Apr. 29, 2018	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Number of Shares Repurchased (in shares)	23,749,647	16,738,758	7,010,889
Average Price Paid Per Share (usd per share)	$ 63.07	$ 62.96	$ 63.34
Total Purchase Price	$ 1,498	$ 1,054	$ 444

Income Taxes - Income Tax Domes

Income Taxes - Income Tax Domestic and Foreign (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S.	$ 4,557	$ 3,686	$ 3,274
Puerto Rico	46	231	(113)
Income before income taxes	$ 4,603	$ 3,917	$ 3,161

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current tax benefit (expense)
Federal	$ 24	$ 39	$ 0
State	(70)	(63)	(28)
Puerto Rico	2	(25)	(1)
Total current tax expense	(44)	(49)	(29)
Deferred tax benefit (expense)
Federal	(954)	(750)	1,182
State	(125)	(160)	173
Puerto Rico	(12)	(70)	49
Total deferred tax (expense) benefit	(1,091)	(980)	1,404
Total income tax (expense) benefit	$ (1,135)	$ (1,029)	$ 1,375

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory income tax rate	21.00%	21.00%	35.00%
Effect of law and rate changes	0.40%	1.90%	(68.90%)
Change in valuation allowance	(1.80%)	(1.60%)	(11.40%)
State taxes, net of federal benefit	5.10%	4.80%	4.80%
Equity-based compensation	(0.60%)	(0.60%)	(2.40%)
Puerto Rico taxes, net of federal benefit	0.30%	2.40%	(1.50%)
Permanent differences	1.20%	1.30%	0.50%
Federal tax credits, net of reserves	(0.80%)	(2.90%)	0.30%
Other, net	(0.10%)	0.00%	0.10%
Effective income tax rate	24.70%	26.30%	(43.50%)

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Loss carryforwards	$ 823	$ 1,526
Deferred rents	0	784
Lease liability	3,403
Reserves and accruals	659	668
Federal and state tax credits	331	340
Other	903	620
Deferred tax assets, gross	6,119	3,938
Valuation allowance	(129)	(210)	$ (273)
Deferred tax assets, net	5,990	3,728
Deferred tax liabilities
Spectrum licenses	5,902	5,494
Property and equipment	2,506	2,434
Lease right-of-use assets	2,881
Other intangible assets	19	40
Other	289	232
Total deferred tax liabilities	11,597	8,200
Net deferred tax liabilities	$ 5,607	$ 4,472

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Indirect tax effects excluded	$ 63
Alternative minimum tax credit carryforward	23
Foreign tax credits	331	$ 340
Valuation allowance	129	210	$ 273
Unrecognized tax benefits that would impact effective tax rate	367	$ 315
Federal
Income Tax Contingency [Line Items]
Unrecognized tax benefits, net operating loss	470
Operating loss carryforwards	138
Federal | Research Tax Credit Carryforward
Income Tax Contingency [Line Items]
Foreign tax credits	347
State
Income Tax Contingency [Line Items]
Unrecognized tax benefits, net operating loss	710
Operating loss carryforwards	$ 282

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning of year	$ 462	$ 412	$ 410
Gross decreases to tax positions in prior periods	(7)		(10)
Gross increases to tax positions in prior periods		6
Gross increases due to current period business acquisitions	0	10	0
Gross increases to current period tax positions	59	34	12
Unrecognized tax benefits, end of year	$ 514	$ 462	$ 412

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 751	$ 870	$ 939	$ 908	$ 640	$ 795	$ 782	$ 671	$ 3,468	$ 2,888	$ 4,536
Less: Dividends on mandatory convertible preferred stock									0	0	(55)
Net income attributable to common stockholders	$ 751	$ 870	$ 939	$ 908	$ 640	$ 795	$ 782	$ 671	3,468	2,888	4,481
Add: Dividends related to mandatory convertible preferred stock									0	0	55
Net income attributable to common stockholders									$ 3,468	$ 2,888	$ 4,536
Weighted average shares outstanding - basic (in shares)	856,294,467	854,578,241	854,368,443	851,223,498	849,102,785	847,087,120	847,660,488	855,222,664	854,143,751	849,744,152	831,850,073
Effect of dilutive securities:
Outstanding stock options and unvested stock awards (in shares)									9,289,760	8,546,022	9,200,873
Mandatory convertible preferred stock (in shares)									0	0	30,736,504
Weighted average shares outstanding - diluted (in shares)	864,158,739	862,690,751	860,135,593	858,643,481	856,344,347	853,852,764	852,040,670	862,244,084	863,433,511	858,290,174	871,787,450
Earnings per share - basic (in USD per share)	$ 0.88	$ 1.02	$ 1.10	$ 1.07	$ 0.75	$ 0.94	$ 0.92	$ 0.78	$ 4.06	$ 3.40	$ 5.39
Earnings per share - diluted (in USD per share)	$ 0.87	$ 1.01	$ 1.09	$ 1.06	$ 0.75	$ 0.93	$ 0.92	$ 0.78	$ 4.02	$ 3.36	$ 5.20
Outstanding stock options and unvested stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)									16,359	148,422	33,980

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - Mandatory Convertible Preferred Stock Series A - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Preferred shares authorized (in shares)	100,000,000
Preferred stock, par value (in USD per share)	$ 0.00001
Preferred shares outstanding (in shares)	0	0

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Interest payments for financing leases	$ 82
Additional operating leases not yet commenced, payments due	$ 341
Device upgrade period	18 months
Due in 2019		$ 2,700
Due in 2020 and 2021		4,700
Due in 2022 and 2023		3,300
Due thereafter		3,800
Rent expense under operating leases		3,000
Capital leased assets, gross	$ 3,100
Capital leased assets, accumulated amortization		$ 867
Minimum
Lessee, Lease, Description [Line Items]
Lessee leasing arrangements, operating leases, term of contract (years)	5 years	5 years
Option to extend lease term	5 years
Lessee leasing arrangements, finance leases, term of contract	2 years
Maximum
Lessee, Lease, Description [Line Items]
Lessee leasing arrangements, operating leases, term of contract (years)	10 years	10 years
Option to extend lease term	35 years
Lessee leasing arrangements, finance leases, term of contract	5 years

Leases - Schedule of Lease Expe

Leases - Schedule of Lease Expense (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating lease expense	$ 2,558
Financing lease expense:
Amortization of right-of-use assets	523
Interest on lease liabilities	82
Total financing lease expense	605
Variable lease expense	243
Total lease expense	$ 3,406

Leases - Schedule of Informatio

Leases - Schedule of Information Related to Lease Term and Discount Rate (Details)	Dec. 31, 2019
Weighted Average Remaining Lease Term (Years)
Operating leases	6 years
Financing leases	3 years
Weighted Average Discount Rate
Operating leases	4.80%
Financing leases	4.00%

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Operating and Finance Lease Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019
Operating Leases
2020	$ 2,754
2021	2,583
2022	2,311
2023	1,908
2024	1,615
Thereafter	3,797
Total lease payments	14,968
Less imputed interest	2,142
Total	12,826	$ 11,364
Finance Leases
2020	1,013
2021	733
2022	414
2023	101
2024	71
Thereafter	115
Total lease payments	2,447
Less imputed interest	144
Total	$ 2,303	$ 2,016

Leases - Leased Wireless Device

Leases - Leased Wireless Devices (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ (33,118)		$ (31,297)
Property and equipment, net	21,984	$ 21,020	23,359
Leased wireless devices, gross			1,159
Accumulated depreciation			(622)
Leased wireless devices, net			537
Leased wireless devices
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,139		$ 1,159
Accumulated depreciation	(407)
Property and equipment, net	$ 732

Leases - Schedule of Future M_2

Leases - Schedule of Future Minimum Payments Expected to be Received (under 842) (Details) $ in Millions	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 417
2021	99
Total	$ 516

Leases - Schedule of Future M_3

Leases - Schedule of Future Minimum Payments Expected to be Received (under 840) (Details) $ in Millions	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 419
2020	59
Total	$ 478

Leases - Schedule of Future M_4

Leases - Schedule of Future Minimum Payments Required Under Capital Leases (Details) $ in Millions	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 909
2020	631
2021	389
2022	102
2023	66
Thereafter	106
Total	2,203
Interest	143
Maintenance	$ 45

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Oct. 31, 2018
Operating Leased Assets [Line Items]
Purchase obligation due 2020	$ 3,600
Purchase obligation due 2021 and 2022	3,300
Purchase obligation due 2023 and 2024	1,600
Purchase obligation due thereafter	1,400
Commitments due 2020	164
Commitments due 2021 and 2022	267
Commitments due 2023 and 2024	171
Commitments due thereafter	196
Interest Rate Contract | Cash Flow Hedging
Operating Leased Assets [Line Items]
Aggregate notional amount			$ 9,600
Fair value of derivative instrument	1,200	$ 447
Sprint
Operating Leased Assets [Line Items]
Total long-term lease commitment	$ 481

Additional Financial Informat_3

Additional Financial Information - Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Supplemental Financial Statement Elements [Abstract]
Accounts payable	$ 4,322		$ 5,487
Payroll and related benefits	802		709
Property and other taxes, including payroll	682		642
Interest	227		227
Commissions	251		243
Network decommissioning	0		65
Toll and interconnect	156		157
Advertising	127		76
Other	179		135
Accounts payable and accrued liabilities	6,746	$ 7,676	7,741
Accounts Payable and Accrued Liabilities
Accounts Payable and Accrued Liabilities [Line Items]
Outstanding checks	$ 463		$ 630

Additional Financial Informat_4

Additional Financial Information - Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Reimbursement of certain administrative expenses	$ 11	$ 11	$ 11
Affiliated Entity
Related Party Transaction [Line Items]
Discount related to roaming expenses	(9)	0	0
Fees incurred for use of the T-Mobile brand	88	84	79
Expenses for telecommunications and IT services	0	0	12
International long distance agreement	$ 39	$ 36	$ 55

Guarantor Financial Informati_3

Guarantor Financial Information - Condensed Consolidating Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 1,528		$ 1,203
Accounts receivable, net	1,888		1,769
Equipment installment plan receivables, net	2,600		2,538
Accounts receivable from affiliates	20		11
Inventory	964		1,084
Other current assets	2,305	$ 1,598	1,676
Total current assets	9,305		8,281
Property and equipment, net	21,984	21,020	23,359
Operating lease right-of-use assets	10,933	9,251
Financing lease right-of-use assets	2,715	2,271
Goodwill	1,930		1,901
Spectrum licenses	36,465		35,559
Other intangible assets, net	115	186	198
Investments in subsidiaries, net	0		0
Intercompany receivables and note receivables	0		0
Equipment installment plan receivables due after one year, net	1,583		1,547
Other assets	1,891	1,552	1,623
Total assets	86,921		72,468
Current liabilities
Accounts payable and accrued liabilities	6,746	7,676	7,741
Payables to affiliates	187		200
Short-term debt	25		841
Deferred revenue	631		698
Short-term operating lease liabilities	2,287
Short-term financing lease liabilities	957
Other current liabilities	1,673	815	787
Total current liabilities	12,506		10,267
Long-term debt	10,958		12,124
Long-term debt to affiliates	13,986		14,582
Tower obligations	2,236	2,212	2,557
Deferred tax liabilities	5,607	4,703	4,472
Operating lease liabilities	10,539
Financing lease liabilities	1,346
Deferred rent expense			2,781
Negative carrying value of subsidiaries, net	0		0
Intercompany payables and debt	0		0
Other long-term liabilities	954	$ 903	967
Total long-term liabilities	45,626		37,483
Total stockholders' equity (deficit)	28,789		24,718	$ 22,559	$ 18,236
Total liabilities and stockholders' equity	86,921		72,468
Consolidating and Eliminating Adjustments
Current assets
Cash and cash equivalents	0		0
Accounts receivable, net	0		0
Equipment installment plan receivables, net	0		0
Accounts receivable from affiliates	0		0
Inventory	0		0
Other current assets	0		0
Total current assets	0		0
Property and equipment, net	0		0
Operating lease right-of-use assets	0
Financing lease right-of-use assets	0
Goodwill	0		0
Spectrum licenses	0		0
Other intangible assets, net	0		0
Investments in subsidiaries, net	(80,204)		(71,830)
Intercompany receivables and note receivables	(3,464)		(5,174)
Equipment installment plan receivables due after one year, net	0		0
Other assets	(163)		(141)
Total assets	(83,831)		(77,145)
Current liabilities
Accounts payable and accrued liabilities	0		0
Payables to affiliates	0		0
Short-term debt	0		0
Deferred revenue	0		0
Short-term operating lease liabilities	0
Short-term financing lease liabilities	0
Other current liabilities	0		0
Total current liabilities	0		0
Long-term debt	0		0
Long-term debt to affiliates	0		0
Tower obligations	0		0
Deferred tax liabilities	(163)		(141)
Operating lease liabilities	0
Financing lease liabilities	0
Deferred rent expense			0
Negative carrying value of subsidiaries, net	(864)		(676)
Intercompany payables and debt	(3,464)		(5,174)
Other long-term liabilities	0		0
Total long-term liabilities	(4,491)		(5,991)
Total stockholders' equity (deficit)	(79,340)		(71,154)
Total liabilities and stockholders' equity	(83,831)		(77,145)
Parent | Reportable Legal Entities
Current assets
Cash and cash equivalents	5		2
Accounts receivable, net	0		0
Equipment installment plan receivables, net	0		0
Accounts receivable from affiliates	0		0
Inventory	0		0
Other current assets	0		0
Total current assets	5		2
Property and equipment, net	0		0
Operating lease right-of-use assets	0
Financing lease right-of-use assets	0
Goodwill	0		0
Spectrum licenses	0		0
Other intangible assets, net	0		0
Investments in subsidiaries, net	28,898		25,314
Intercompany receivables and note receivables	0		0
Equipment installment plan receivables due after one year, net	0		0
Other assets	0		0
Total assets	28,903		25,316
Current liabilities
Accounts payable and accrued liabilities	0		0
Payables to affiliates	0		0
Short-term debt	0		0
Deferred revenue	0		0
Short-term operating lease liabilities	0
Short-term financing lease liabilities	0
Other current liabilities	0		0
Total current liabilities	0		0
Long-term debt	0		0
Long-term debt to affiliates	0		0
Tower obligations	0		0
Deferred tax liabilities	0		0
Operating lease liabilities	0
Financing lease liabilities	0
Deferred rent expense			0
Negative carrying value of subsidiaries, net	0		0
Intercompany payables and debt	114		598
Other long-term liabilities	0		0
Total long-term liabilities	114		598
Total stockholders' equity (deficit)	28,789		24,718
Total liabilities and stockholders' equity	28,903		25,316
Issuer | Reportable Legal Entities
Current assets
Cash and cash equivalents	1		1
Accounts receivable, net	0		0
Equipment installment plan receivables, net	0		0
Accounts receivable from affiliates	0		0
Inventory	0		0
Other current assets	646		0
Total current assets	647		1
Property and equipment, net	0		0
Operating lease right-of-use assets	0
Financing lease right-of-use assets	0
Goodwill	0		0
Spectrum licenses	0		0
Other intangible assets, net	0		0
Investments in subsidiaries, net	51,306		46,516
Intercompany receivables and note receivables	3,464		5,174
Equipment installment plan receivables due after one year, net	0		0
Other assets	18		7
Total assets	55,435		51,698
Current liabilities
Accounts payable and accrued liabilities	252		228
Payables to affiliates	145		157
Short-term debt	25		0
Deferred revenue	0		0
Short-term operating lease liabilities	0
Short-term financing lease liabilities	0
Other current liabilities	1,171		447
Total current liabilities	1,593		832
Long-term debt	10,958		10,950
Long-term debt to affiliates	13,986		14,582
Tower obligations	0		0
Deferred tax liabilities	0		0
Operating lease liabilities	0
Financing lease liabilities	0
Deferred rent expense			0
Negative carrying value of subsidiaries, net	0		0
Intercompany payables and debt	0		0
Other long-term liabilities	0		20
Total long-term liabilities	24,944		25,552
Total stockholders' equity (deficit)	28,898		25,314
Total liabilities and stockholders' equity	55,435		51,698
Guarantor Subsidiaries | Reportable Legal Entities
Current assets
Cash and cash equivalents	1,350		1,082
Accounts receivable, net	1,616		1,510
Equipment installment plan receivables, net	2,600		2,538
Accounts receivable from affiliates	20		11
Inventory	964		1,084
Other current assets	975		1,032
Total current assets	7,525		7,257
Property and equipment, net	21,790		23,113
Operating lease right-of-use assets	10,933
Financing lease right-of-use assets	2,715
Goodwill	1,930		1,901
Spectrum licenses	36,465		35,559
Other intangible assets, net	115		198
Investments in subsidiaries, net	0		0
Intercompany receivables and note receivables	0		0
Equipment installment plan receivables due after one year, net	1,583		1,547
Other assets	1,797		1,540
Total assets	84,853		71,115
Current liabilities
Accounts payable and accrued liabilities	6,236		7,263
Payables to affiliates	42		43
Short-term debt	0		841
Deferred revenue	631		698
Short-term operating lease liabilities	2,287
Short-term financing lease liabilities	957
Other current liabilities	139		164
Total current liabilities	10,292		9,009
Long-term debt	0		1,174
Long-term debt to affiliates	0		0
Tower obligations	75		384
Deferred tax liabilities	5,770		4,613
Operating lease liabilities	10,539
Financing lease liabilities	1,346
Deferred rent expense			2,781
Negative carrying value of subsidiaries, net	864		676
Intercompany payables and debt	2,968		4,258
Other long-term liabilities	937		926
Total long-term liabilities	22,499		14,812
Total stockholders' equity (deficit)	52,062		47,294
Total liabilities and stockholders' equity	84,853		71,115
Non-Guarantor Subsidiaries | Reportable Legal Entities
Current assets
Cash and cash equivalents	172		118
Accounts receivable, net	272		259
Equipment installment plan receivables, net	0		0
Accounts receivable from affiliates	0		0
Inventory	0		0
Other current assets	684		644
Total current assets	1,128		1,021
Property and equipment, net	194		246
Operating lease right-of-use assets	0
Financing lease right-of-use assets	0
Goodwill	0		0
Spectrum licenses	0		0
Other intangible assets, net	0		0
Investments in subsidiaries, net	0		0
Intercompany receivables and note receivables	0		0
Equipment installment plan receivables due after one year, net	0		0
Other assets	239		217
Total assets	1,561		1,484
Current liabilities
Accounts payable and accrued liabilities	258		250
Payables to affiliates	0		0
Short-term debt	0		0
Deferred revenue	0		0
Short-term operating lease liabilities	0
Short-term financing lease liabilities	0
Other current liabilities	363		176
Total current liabilities	621		426
Long-term debt	0		0
Long-term debt to affiliates	0		0
Tower obligations	2,161		2,173
Deferred tax liabilities	0		0
Operating lease liabilities	0
Financing lease liabilities	0
Deferred rent expense			0
Negative carrying value of subsidiaries, net	0		0
Intercompany payables and debt	382		318
Other long-term liabilities	17		21
Total long-term liabilities	2,560		2,512
Total stockholders' equity (deficit)	(1,620)		(1,454)
Total liabilities and stockholders' equity	$ 1,561		$ 1,484

Guarantor Financial Informati_4

Guarantor Financial Information - Condensed Consolidating Statement of Comprehensive Income Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Revenues	$ 11,878	$ 11,061	$ 10,979	$ 11,080	$ 11,445	$ 10,839	$ 10,571	$ 10,455	$ 44,998	$ 43,310	$ 40,604
Operating expenses
Selling, general and administrative									14,139	13,161	12,259
Depreciation and amortization									6,616	6,486	5,984
Gains on disposal of spectrum licenses									0	0	(235)
Total operating expenses									39,276	38,001	35,716
Operating income	1,234	1,471	1,541	1,476	1,137	1,440	1,450	1,282	5,722	5,309	4,888
Other income (expense)
Interest expense									(727)	(835)	(1,111)
Interest expense to affiliates									(408)	(522)	(560)
Interest income									24	19	17
Other (expense) income, net									(8)	(54)	(73)
Total other expense, net									(1,119)	(1,392)	(1,727)
Income before income taxes									4,603	3,917	3,161
Income tax expense									(1,135)	(1,029)	1,375
Earnings of subsidiaries									0	0	0
Net income	751	870	939	908	640	795	782	671	3,468	2,888	4,536
Preferred Stock Dividends and Other Adjustments									0	0	(55)
Net income attributable to common stockholders	751	870	939	908	640	795	782	671	3,468	2,888	4,481
Net income	$ 751	$ 870	$ 939	$ 908	$ 640	$ 795	$ 782	$ 671	3,468	2,888	4,536
Other comprehensive (loss) income, net of tax
Other comprehensive (loss) income, net of tax									(536)	(332)	7
Total comprehensive income									2,932	2,556	4,543
Service
Revenues
Revenues									33,994	31,992	30,160
Operating expenses
Cost of services and equipment sales									6,622	6,307	6,100
Product
Revenues
Revenues									9,840	10,009	9,375
Operating expenses
Cost of services and equipment sales									11,899	12,047	11,608
Other revenues
Revenues
Revenues									1,164	1,309	1,069
Consolidating and Eliminating Adjustments
Revenues
Revenues									(1,660)	(1,240)	(1,117)
Operating expenses
Selling, general and administrative									(1,333)	(1,038)	(873)
Depreciation and amortization									0	0	0
Gains on disposal of spectrum licenses											0
Total operating expenses									(1,660)	(1,240)	(1,117)
Operating income									0	0	0
Other income (expense)
Interest expense									0	0	0
Interest expense to affiliates									21	21	23
Interest income									(21)	(21)	(23)
Other (expense) income, net									0	0	0
Total other expense, net									0	0	0
Income before income taxes									0	0	0
Income tax expense									0	0	0
Earnings of subsidiaries									(7,818)	(6,904)	(10,440)
Net income									(7,818)	(6,904)	(10,440)
Preferred Stock Dividends and Other Adjustments											0
Net income attributable to common stockholders											(10,440)
Net income									(7,818)	(6,904)	(10,440)
Other comprehensive (loss) income, net of tax
Other comprehensive (loss) income, net of tax									350	216	(14)
Total comprehensive income									(7,468)	(6,688)	(10,454)
Consolidating and Eliminating Adjustments | Service
Revenues
Revenues									(1,277)	(978)	(847)
Operating expenses
Cost of services and equipment sales									(111)	0	0
Consolidating and Eliminating Adjustments | Product
Revenues
Revenues									(216)	(201)	(245)
Operating expenses
Cost of services and equipment sales									(216)	(202)	(244)
Consolidating and Eliminating Adjustments | Other revenues
Revenues
Revenues									(167)	(61)	(25)
Parent | Reportable Legal Entities
Revenues
Revenues									0	0	0
Operating expenses
Selling, general and administrative									0	0	0
Depreciation and amortization									0	0	0
Gains on disposal of spectrum licenses											0
Total operating expenses									0	0	0
Operating income									0	0	0
Other income (expense)
Interest expense									0	0	0
Interest expense to affiliates									0	0	0
Interest income									0	0	1
Other (expense) income, net									0	0	0
Total other expense, net									0	0	1
Income before income taxes									0	0	1
Income tax expense									0	0	0
Earnings of subsidiaries									3,468	2,888	4,535
Net income									3,468	2,888	4,536
Preferred Stock Dividends and Other Adjustments											(55)
Net income attributable to common stockholders											4,481
Net income									3,468	2,888	4,536
Other comprehensive (loss) income, net of tax
Other comprehensive (loss) income, net of tax									(536)	(332)	7
Total comprehensive income									2,932	2,556	4,543
Parent | Reportable Legal Entities | Service
Revenues
Revenues									0	0	0
Operating expenses
Cost of services and equipment sales									0	0	0
Parent | Reportable Legal Entities | Product
Revenues
Revenues									0	0	0
Operating expenses
Cost of services and equipment sales									0	0	0
Parent | Reportable Legal Entities | Other revenues
Revenues
Revenues									0	0	0
Issuer | Reportable Legal Entities
Revenues
Revenues									19	29	3
Operating expenses
Selling, general and administrative									16	11	0
Depreciation and amortization									0	0	0
Gains on disposal of spectrum licenses											0
Total operating expenses									16	11	0
Operating income									3	18	3
Other income (expense)
Interest expense									(454)	(528)	(811)
Interest expense to affiliates									(409)	(522)	(560)
Interest income									22	23	29
Other (expense) income, net									(13)	(87)	(88)
Total other expense, net									(854)	(1,114)	(1,430)
Income before income taxes									(851)	(1,096)	(1,427)
Income tax expense									0	0	0
Earnings of subsidiaries									4,319	3,984	5,962
Net income									3,468	2,888	4,535
Preferred Stock Dividends and Other Adjustments											0
Net income attributable to common stockholders											4,535
Net income									3,468	2,888	4,535
Other comprehensive (loss) income, net of tax
Other comprehensive (loss) income, net of tax									(536)	(332)	7
Total comprehensive income									2,932	2,556	4,542
Issuer | Reportable Legal Entities | Service
Revenues
Revenues									0	0	0
Operating expenses
Cost of services and equipment sales									0	0	0
Issuer | Reportable Legal Entities | Product
Revenues
Revenues									0	0	0
Operating expenses
Cost of services and equipment sales									0	0	0
Issuer | Reportable Legal Entities | Other revenues
Revenues
Revenues									19	29	3
Guarantor Subsidiaries | Reportable Legal Entities
Revenues
Revenues									43,430	41,959	39,393
Operating expenses
Selling, general and administrative									14,467	13,296	12,276
Depreciation and amortization									6,564	6,422	5,914
Gains on disposal of spectrum licenses											(235)
Total operating expenses									38,672	37,240	34,880
Operating income									4,758	4,719	4,513
Other income (expense)
Interest expense									(88)	(114)	(109)
Interest expense to affiliates									(20)	(21)	(23)
Interest income									20	16	10
Other (expense) income, net									6	33	16
Total other expense, net									(82)	(86)	(106)
Income before income taxes									4,676	4,633	4,407
Income tax expense									(965)	(950)	1,527
Earnings of subsidiaries									31	32	(57)
Net income									3,742	3,715	5,877
Preferred Stock Dividends and Other Adjustments											0
Net income attributable to common stockholders											5,877
Net income									3,742	3,715	5,877
Other comprehensive (loss) income, net of tax
Other comprehensive (loss) income, net of tax									186	116	7
Total comprehensive income									3,928	3,831	5,884
Guarantor Subsidiaries | Reportable Legal Entities | Service
Revenues
Revenues									32,268	30,637	28,894
Operating expenses
Cost of services and equipment sales									6,733	6,283	6,076
Guarantor Subsidiaries | Reportable Legal Entities | Product
Revenues
Revenues									10,053	10,209	9,620
Operating expenses
Cost of services and equipment sales									10,908	11,239	10,849
Guarantor Subsidiaries | Reportable Legal Entities | Other revenues
Revenues
Revenues									1,109	1,113	879
Non-Guarantor Subsidiaries | Reportable Legal Entities
Revenues
Revenues									3,209	2,562	2,325
Operating expenses
Selling, general and administrative									989	892	856
Depreciation and amortization									52	64	70
Gains on disposal of spectrum licenses											0
Total operating expenses									2,248	1,990	1,953
Operating income									961	572	372
Other income (expense)
Interest expense									(185)	(193)	(191)
Interest expense to affiliates									0	0	0
Interest income									3	1	0
Other (expense) income, net									(1)	0	(1)
Total other expense, net									(183)	(192)	(192)
Income before income taxes									778	380	180
Income tax expense									(170)	(79)	(152)
Earnings of subsidiaries									0	0	0
Net income									608	301	28
Preferred Stock Dividends and Other Adjustments											0
Net income attributable to common stockholders											28
Net income									608	301	28
Other comprehensive (loss) income, net of tax
Other comprehensive (loss) income, net of tax									0	0	0
Total comprehensive income									608	301	28
Non-Guarantor Subsidiaries | Reportable Legal Entities | Service
Revenues
Revenues									3,003	2,333	2,113
Operating expenses
Cost of services and equipment sales									0	24	24
Non-Guarantor Subsidiaries | Reportable Legal Entities | Product
Revenues
Revenues									3	1	0
Operating expenses
Cost of services and equipment sales									1,207	1,010	1,003
Non-Guarantor Subsidiaries | Reportable Legal Entities | Other revenues
Revenues
Revenues									$ 203	$ 228	$ 212

Guarantor Financial Informati_5

Guarantor Financial Information - Condensed Consolidating Statement of Cash Flows Information (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net cash provided by operating activities		$ 6,824	$ 3,899	$ 3,831
Investing activities
Purchases of property and equipment		(6,391)	(5,541)	(5,237)
Purchases of spectrum licenses and other intangible assets, including deposits		(967)	(127)	(5,828)
Proceeds from sales of tower sites	$ 38	38	0	0
Proceeds related to beneficial interests in securitization transactions		3,876	5,406	4,319
Net cash related to derivative contracts under collateral exchange arrangements	632	(632)	0	0
Acquisition of companies, net of cash acquired		(31)	(338)	0
Equity investment in subsidiary			0	0
Other, net		(18)	21	1
Net cash used in investing activities		(4,125)	(579)	(6,745)
Financing activities
Proceeds from issuance of long-term debt		0	2,494	10,480
Proceeds from borrowing on revolving credit facility		2,340	6,265	2,910
Repayments of revolving credit facility		(2,340)	(6,265)	(2,910)
Repayments of financing lease obligations		(798)	(700)	(486)
Repayments of short-term debt for purchases of inventory, property and equipment, net		(775)	(300)	(300)
Repayments of long-term debt		(600)	(3,349)	(10,230)
Repurchases of common stock		0	(1,071)	(427)
Intercompany advances, net		0	0	0
Equity investment from parent			0	0
Tax withholdings on share-based awards		(156)	(146)	(166)
Dividends on preferred stock				(55)
Cash payments for debt prepayment or debt extinguishment costs		(28)	(212)	(188)
Intercompany dividend paid		0	0	0
Other, net		(17)	(52)	5
Net cash used in financing activities		(2,374)	(3,336)	(1,367)
Change in cash and cash equivalents		325	(16)	(4,281)
Beginning of period		1,203	1,219	5,500
End of period	1,528	1,528	1,203	1,219
Consolidating and Eliminating Adjustments
Operating activities
Net cash provided by operating activities		(555)	(220)	(100)
Investing activities
Purchases of property and equipment		0	0	0
Purchases of spectrum licenses and other intangible assets, including deposits		0	0	0
Proceeds from sales of tower sites		0
Proceeds related to beneficial interests in securitization transactions		0	0	0
Net cash related to derivative contracts under collateral exchange arrangements		0
Acquisition of companies, net of cash acquired		0	0
Equity investment in subsidiary			43	308
Other, net		0	0	0
Net cash used in investing activities		0	43	308
Financing activities
Proceeds from issuance of long-term debt			0	0
Proceeds from borrowing on revolving credit facility		0	0	0
Repayments of revolving credit facility		0	0	0
Repayments of financing lease obligations		0	0	0
Repayments of short-term debt for purchases of inventory, property and equipment, net		0	0
Repayments of long-term debt		0	0	0
Repurchases of common stock			0	0
Intercompany advances, net		0	0	0
Equity investment from parent			(43)	(308)
Tax withholdings on share-based awards		0	0	0
Dividends on preferred stock				0
Cash payments for debt prepayment or debt extinguishment costs		0	0	0
Intercompany dividend paid		555	220	100
Other, net		0	0	0
Net cash used in financing activities		555	177	(208)
Change in cash and cash equivalents		0	0	0
Beginning of period		0	0	0
End of period	0	0	0	0
Parent | Reportable Legal Entities
Operating activities
Net cash provided by operating activities		0	0	1
Investing activities
Purchases of property and equipment		0	0	0
Purchases of spectrum licenses and other intangible assets, including deposits		0	0	0
Proceeds from sales of tower sites		0
Proceeds related to beneficial interests in securitization transactions		0	0	0
Net cash related to derivative contracts under collateral exchange arrangements		0
Acquisition of companies, net of cash acquired		0	0
Equity investment in subsidiary			0	(308)
Other, net		0	0	0
Net cash used in investing activities		0	0	(308)
Financing activities
Proceeds from issuance of long-term debt			0	0
Proceeds from borrowing on revolving credit facility		0	0	0
Repayments of revolving credit facility		0	0	0
Repayments of financing lease obligations		0	0	0
Repayments of short-term debt for purchases of inventory, property and equipment, net		0	0
Repayments of long-term debt		0	0	0
Repurchases of common stock			(1,071)	(427)
Intercompany advances, net		1	995	484
Equity investment from parent			0	0
Tax withholdings on share-based awards		0	0	0
Dividends on preferred stock				(55)
Cash payments for debt prepayment or debt extinguishment costs		0	0	0
Intercompany dividend paid		0	0	0
Other, net		2	4	21
Net cash used in financing activities		3	(72)	23
Change in cash and cash equivalents		3	(72)	(284)
Beginning of period		2	74	358
End of period	5	5	2	74
Issuer | Reportable Legal Entities
Operating activities
Net cash provided by operating activities		(752)	(1,254)	(1,613)
Investing activities
Purchases of property and equipment		0	0	0
Purchases of spectrum licenses and other intangible assets, including deposits		0	0	0
Proceeds from sales of tower sites		0
Proceeds related to beneficial interests in securitization transactions		0	0	0
Net cash related to derivative contracts under collateral exchange arrangements		(632)
Acquisition of companies, net of cash acquired		(32)	0
Equity investment in subsidiary			0	0
Other, net		(12)	(7)	0
Net cash used in investing activities		(676)	(7)	0
Financing activities
Proceeds from issuance of long-term debt			2,494	10,480
Proceeds from borrowing on revolving credit facility		2,340	6,265	2,910
Repayments of revolving credit facility		0	0	0
Repayments of financing lease obligations		0	0	0
Repayments of short-term debt for purchases of inventory, property and equipment, net		0	0
Repayments of long-term debt		0	0	0
Repurchases of common stock			0	0
Intercompany advances, net		(912)	(7,498)	(14,817)
Equity investment from parent			0	308
Tax withholdings on share-based awards		0	0	0
Dividends on preferred stock				0
Cash payments for debt prepayment or debt extinguishment costs		0	0	0
Intercompany dividend paid		0	0	0
Other, net		0	0	0
Net cash used in financing activities		1,428	1,261	(1,119)
Change in cash and cash equivalents		0	0	(2,732)
Beginning of period		1	1	2,733
End of period	1	1	1	1
Guarantor Subsidiaries | Reportable Legal Entities
Operating activities
Net cash provided by operating activities		11,338	10,414	9,761
Investing activities
Purchases of property and equipment		(6,391)	(5,536)	(5,237)
Purchases of spectrum licenses and other intangible assets, including deposits		(967)	(127)	(5,828)
Proceeds from sales of tower sites		38
Proceeds related to beneficial interests in securitization transactions		37	53	43
Net cash related to derivative contracts under collateral exchange arrangements		0
Acquisition of companies, net of cash acquired		1	(338)
Equity investment in subsidiary			(43)	0
Other, net		(6)	28	1
Net cash used in investing activities		(7,288)	(5,963)	(11,021)
Financing activities
Proceeds from issuance of long-term debt			0	0
Proceeds from borrowing on revolving credit facility		0	0	0
Repayments of revolving credit facility		(2,340)	(6,265)	(2,910)
Repayments of financing lease obligations		(798)	(700)	(486)
Repayments of short-term debt for purchases of inventory, property and equipment, net		(775)	(300)
Repayments of long-term debt		(600)	(3,349)	(10,230)
Repurchases of common stock			0	0
Intercompany advances, net		934	6,530	14,300
Equity investment from parent			43	0
Tax withholdings on share-based awards		(156)	(146)	(166)
Dividends on preferred stock				0
Cash payments for debt prepayment or debt extinguishment costs		(28)	(212)	(188)
Intercompany dividend paid		0	0	0
Other, net		(19)	(56)	(16)
Net cash used in financing activities		(3,782)	(4,455)	4
Change in cash and cash equivalents		268	(4)	(1,256)
Beginning of period		1,082	1,086	2,342
End of period	1,350	1,350	1,082	1,086
Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating activities
Net cash provided by operating activities		(3,207)	(5,041)	(4,218)
Investing activities
Purchases of property and equipment		0	(5)	0
Purchases of spectrum licenses and other intangible assets, including deposits		0	0	0
Proceeds from sales of tower sites		0
Proceeds related to beneficial interests in securitization transactions		3,839	5,353	4,276
Net cash related to derivative contracts under collateral exchange arrangements		0
Acquisition of companies, net of cash acquired		0	0
Equity investment in subsidiary			0	0
Other, net		0	0	0
Net cash used in investing activities		3,839	5,348	4,276
Financing activities
Proceeds from issuance of long-term debt			0	0
Proceeds from borrowing on revolving credit facility		0	0	0
Repayments of revolving credit facility		0	0	0
Repayments of financing lease obligations		0	0	0
Repayments of short-term debt for purchases of inventory, property and equipment, net		0	0
Repayments of long-term debt		0	0	0
Repurchases of common stock			0	0
Intercompany advances, net		(23)	(27)	33
Equity investment from parent			0	0
Tax withholdings on share-based awards		0	0	0
Dividends on preferred stock				0
Cash payments for debt prepayment or debt extinguishment costs		0	0	0
Intercompany dividend paid		(555)	(220)	(100)
Other, net		0	0	0
Net cash used in financing activities		(578)	(247)	(67)
Change in cash and cash equivalents		54	60	(9)
Beginning of period		118	58	67
End of period	$ 172	$ 172	$ 118	$ 58

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information [Abstract]
Total revenues	$ 11,878	$ 11,061	$ 10,979	$ 11,080	$ 11,445	$ 10,839	$ 10,571	$ 10,455	$ 44,998	$ 43,310	$ 40,604
Operating income	1,234	1,471	1,541	1,476	1,137	1,440	1,450	1,282	5,722	5,309	4,888
Net income	751	870	939	908	640	795	782	671	3,468	2,888	4,536
Net income attributable to common stockholders	$ 751	$ 870	$ 939	$ 908	$ 640	$ 795	$ 782	$ 671	$ 3,468	$ 2,888	$ 4,481
Earnings per share - basic (in USD per share)	$ 0.88	$ 1.02	$ 1.10	$ 1.07	$ 0.75	$ 0.94	$ 0.92	$ 0.78	$ 4.06	$ 3.40	$ 5.39
Earnings per share - diluted (in USD per share)	$ 0.87	$ 1.01	$ 1.09	$ 1.06	$ 0.75	$ 0.93	$ 0.92	$ 0.78	$ 4.02	$ 3.36	$ 5.20
Weighted average shares outstanding - basic (in shares)	856,294,467	854,578,241	854,368,443	851,223,498	849,102,785	847,087,120	847,660,488	855,222,664	854,143,751	849,744,152	831,850,073
Weighted average shares outstanding - diluted (in shares)	864,158,739	862,690,751	860,135,593	858,643,481	856,344,347	853,852,764	852,040,670	862,244,084	863,433,511	858,290,174	871,787,450