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.

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.

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

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 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 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 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.

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.

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.

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.

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.

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:

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.

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.

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.

•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.

•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.

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.

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).

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

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.

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.

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.

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.

We expense the cost of advertising and other promotional expenditures to market our services and products as incurred. For the years ended December 31, 2019, 2018 and 2017, advertising expenses included in Selling, general and administrative expenses in our Consolidated Statements of Comprehensive Income were $1.6 billion, $1.7 billion and $1.8 billion, respectively.

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.

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.

Basic 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. See Note 1 4 - Earnings Per Share for further information.

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.

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.

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.

•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 to five years based on lease contracts in effect at transition on January 1, 2019. The aggregate impact of using hindsight is an estimated decrease in Total operating expenses of $240 million in fiscal year 2019.

•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 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.


	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:

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 have operating leases for cell sites, retail locations, corporate offices and dedicated transportation lines, some of which have escalating rentals during the initial lease term and during subsequent optional renewal periods. We recognize a right-of-use asset and lease liability for operating leases based on the net present value of future minimum lease payments. Lease expense is recognized on a straight-line basis over the non-cancelable lease term and renewal periods that are considered reasonably certain.

We have financing leases for certain network equipment. The financing leases do not have renewal options and contain a bargain purchase option at the end of the lease. We recognize a right-of-use asset and lease liability for financing leases based on the net present value of future minimum lease payments. Lease expense for our financing leases is comprised of the amortization of the right-of-use asset and interest expense recognized based on the effective interest method.

In June 2016, the FASB issued ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” and has since modified the standard with several ASUs (collectively, the “new credit loss standard”). The new credit loss standard requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions and reasonable and supportable forecasts that affect the collectibility of the reported amount. The new credit loss standard will become effective for us beginning on January 1, 2020, and requires a cumulative-effect adjustment to Accumulated deficit as of the beginning of the first reporting period in which the guidance is effective (that is, a modified-retrospective approach).

We will adopt the new credit loss standard on January 1, 2020, and plan to recognize lifetime expected credit losses at the inception of our credit risk exposures whereas we currently recognize credit losses only when it is probable that they have been incurred. We will also recognize expected credit losses on our EIP receivables, excluding consideration of any unamortized discount on those receivables resulting from the imputation of interest. We currently offset our estimate of incurred losses on our EIP receivables by the amount of the related unamortized discounts on those receivables. We have developed an expected credit loss model and are refining the inputs including the forward-looking loss indicators. The estimated impact of the new credit loss standard on our receivables portfolio as of December 31, 2019, would be an increase to our allowance for credit losses of $85 million to $95 million, a decrease to our net deferred tax liabilities of $22 million to $25 million and an increase to our Accumulated deficit of $63 million to $70 million.

In August 2018, the FASB issued ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Topic 350): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract.” The standard aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. We will adopt the standard on a prospective basis beginning on the effective date of January 1, 2020. Upon adoption of the standard, implementation costs are capitalized in the period incurred, which will result in an increase to Other assets in our Consolidated Balance Sheets. These capitalized amounts will be amortized over the term of the hosting arrangement to Cost of services or Selling, general and administrative expenses in our Consolidated Statements of Comprehensive Income based on the nature of the hosting arrangement. The impact of this standard on our Consolidated Financial Statements is dependent on the nature and composition of the hosting arrangements entered into subsequent to adoption.