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Summary of Significant Accounting Policies | 12 Months Ended
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Dec. 31, 2017
Accounting Policies [Abstract] |
Summary of Significant Accounting Policies | 1. Summary of Significant Accounting Policies (All Registrants) General Capitalized terms and abbreviations appearing in the combined notes to financial statements are defined in the glossary. Dollars are in millions, except per share data, unless otherwise noted. The specific Registrant to which disclosures are applicable is identified in parenthetical headings in italics above the applicable disclosure or within the applicable disclosure for each Registrants' related activities and disclosures. Within combined disclosures, amounts are disclosed for any Registrant when significant. Business and Consolidation (PPL) PPL is a utility holding company that, through its regulated subsidiaries, is primarily engaged in: 1) the distribution of electricity in the U.K.; 2) the generation, transmission, distribution and sale of electricity and the distribution and sale of natural gas, primarily in Kentucky; and 3) the transmission, distribution and sale of electricity in Pennsylvania. Headquartered in Allentown, PA, PPL's principal subsidiaries are PPL Global, LKE (including its principal subsidiaries, LG&E and KU) and PPL Electric. PPL's corporate level financing subsidiary is PPL Capital Funding. WPD, a subsidiary of PPL Global, through indirect, wholly owned subsidiaries, operates distribution networks providing electricity service in the U.K. WPD serves end-users in South Wales and southwest and central England. Its principal subsidiaries are WPD (South Wales), WPD (South West), WPD (East Midlands) and WPD (West Midlands). PPL consolidates WPD on a one-month lag. Material events, such as debt issuances that occur in the lag period, are recognized in the current period financial statements. Events that are significant but not material are disclosed. (PPL and PPL Electric) PPL Electric is a cost-based rate-regulated utility subsidiary of PPL. PPL Electric's principal business is the transmission and distribution of electricity to serve retail customers in its franchised territory in eastern and central Pennsylvania and the regulated supply of electricity to retail customers in that territory as a PLR. (PPL, LKE, LG&E and KU) LKE is a utility holding company with cost-based rate-regulated utility operations through its subsidiaries, LG&E and KU. LG&E and KU are engaged in the generation, transmission, distribution and sale of electricity. LG&E also engages in the distribution and sale of natural gas. LG&E and KU maintain their separate identities and serve customers in Kentucky under their respective names. KU also serves customers in Virginia under the Old Dominion Power name and in Tennessee under the KU name. (PPL) "Loss from Discontinued Operations (net of income taxes)" on the 2015 Statement of Income includes the activities of PPL Energy Supply, substantially representing PPL's former Supply segment, which was spun off and distributed to PPL shareowners on June 1, 2015. In addition, the Statement of Cash Flows for the same period separately reports the cash flows of the discontinued operations. See Note 8 for additional information. (All Registrants) The financial statements of the Registrants include each company's own accounts as well as the accounts of all entities in which the company has a controlling financial interest. Entities for which a controlling financial interest is not demonstrated through voting interests are evaluated based on accounting guidance for Variable Interest Entities (VIEs). The Registrants consolidate a VIE when they are determined to have a controlling interest in the VIE, and as a result are the primary beneficiary of the entity. The Registrants are not the primary beneficiary in any VIEs. Investments in entities in which a company has the ability to exercise significant influence but does not have a controlling financial interest are accounted for under the equity method. All other investments are carried at cost or fair value. All significant intercompany transactions have been eliminated. The financial statements of PPL, LKE, LG&E and KU include their share of any undivided interests in jointly owned facilities, as well as their share of the related operating costs of those facilities. See Note 12 for additional information. Regulation (PPL) WPD operates in an incentive-based regulatory structure under distribution licenses granted by Ofgem. Electricity distribution revenues are set by Ofgem for a given time period through price control reviews that are not directly based on cost recovery. The price control formula that governs WPD's allowed revenue is designed to provide economic incentives to minimize operating, capital and financing costs. As a result, WPD is not subject to accounting for the effects of certain types of regulation as prescribed by GAAP and does not record regulatory assets and liabilities. (PPL Electric, LG&E and KU) PPL Electric, LG&E and KU are cost-based rate-regulated utilities for which rates are set by regulators to enable PPL Electric, LG&E and KU to recover the costs of providing electric or gas service, as applicable, and to provide a reasonable return to shareholders. Base rates are generally established based on a future test period. As a result, the financial statements are subject to the accounting for certain types of regulation as prescribed by GAAP and reflect the effects of regulatory actions. Regulatory assets are recognized for the effect of transactions or events where future recovery of underlying costs is probable in regulated customer rates. The effect of such accounting is to defer certain or qualifying costs that would otherwise currently be charged to expense. Regulatory liabilities are recognized for amounts expected to be returned through future regulated customer rates. In certain cases, regulatory liabilities are recorded based on an understanding or agreement with the regulator that rates have been set to recover costs that are expected to be incurred in the future, and the regulated entity is accountable for any amounts charged pursuant to such rates and not yet expended for the intended purpose. The accounting for regulatory assets and regulatory liabilities is based on specific ratemaking decisions or precedent for each transaction or event as prescribed by the FERC or the applicable state regulatory commissions. See Note 6 for additional details regarding regulatory matters. Accounting Records The system of accounts for domestic regulated entities is maintained in accordance with the Uniform System of Accounts prescribed by the FERC and adopted by the applicable state regulatory commissions. (All Registrants) Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Loss Accruals Potential losses are accrued when (1) information is available that indicates it is "probable" that a loss has been incurred, given the likelihood of the uncertain future events and (2) the amount of the loss can be reasonably estimated. Accounting guidance defines "probable" as cases in which "the future event or events are likely to occur." The Registrants continuously assess potential loss contingencies for environmental remediation, litigation claims, regulatory penalties and other events. Loss accruals for environmental remediation are discounted when appropriate. The accrual of contingencies that might result in gains is not recorded, unless realization is assured. Earnings Per Share (PPL) EPS is computed using the two-class method, which is an earnings allocation method for computing EPS that treats a participating security as having rights to earnings that would otherwise have been available to common shareowners. Share-based payment awards that provide recipients a non-forfeitable right to dividends or dividend equivalents are considered participating securities. Price Risk Management (All Registrants) Interest rate contracts are used to hedge exposure to changes in the fair value of debt instruments and to hedge exposure to variability in expected cash flows associated with existing floating-rate debt instruments or forecasted fixed-rate issuances of debt. Foreign currency exchange contracts are used to hedge foreign currency exposures, primarily associated with PPL's investments in U.K. subsidiaries. Similar derivatives may receive different accounting treatment, depending on management's intended use and documentation. Certain contracts may not meet the definition of a derivative because they lack a notional amount or a net settlement provision. In cases where there is no net settlement provision, markets are periodically assessed to determine whether market mechanisms have evolved that would facilitate net settlement. Certain derivative contracts may be excluded from the requirements of derivative accounting treatment because NPNS has been elected. These contracts are accounted for using accrual accounting. Contracts that have been classified as derivative contracts are reflected on the balance sheets at fair value. The portion of derivative positions that deliver within a year are included in "Current Assets" and "Current Liabilities," while the portion of derivative positions that deliver beyond a year are recorded in "Other Noncurrent Assets" and "Deferred Credits and Other Noncurrent Liabilities." Cash inflows and outflows related to derivative instruments are included as a component of operating, investing or financing activities on the Statements of Cash Flows, depending on the classification of the hedged items. PPL and its subsidiaries have elected not to offset net derivative positions against the right to reclaim cash collateral (a receivable) or the obligation to return cash collateral (a payable) under master netting arrangements. (PPL) Processes exist that allow for subsequent review and validation of the contract information as it relates to interest rate and foreign currency derivatives. The accounting department provides the treasury department with guidelines on appropriate accounting classifications for various contract types and strategies. Examples of accounting guidelines provided to the treasury department staff include, but are not limited to:
• | Transactions to lock in an interest rate prior to a debt issuance can be designated as cash flow hedges, to the extent the forecasted debt issuances remain probable of occurring.
• | Cross-currency transactions to hedge interest and principal repayments can be designated as cash flow hedges.
• | Transactions to hedge fluctuations in the fair value of existing debt can be designated as fair value hedges.
• | Transactions to hedge the value of a net investment of foreign operations can be designated as net investment hedges.
• | Derivative transactions that do not qualify for cash flow or net investment hedge treatment are marked to fair value through earnings. These transactions generally include foreign currency forwards and options to hedge GBP-denominated earnings translation risk associated with PPL's U.K. subsidiaries that report their financial statements in GBP. As such, these transactions reduce earnings volatility due solely to changes in foreign currency exchange rates.
(All Registrants)
• | Derivative transactions may be marked to fair value through regulatory assets/liabilities at PPL Electric, LG&E and KU if approved by the appropriate regulatory body. These transactions generally include the effect of interest rate swaps that are included in customer rates.
(PPL and PPL Electric) To meet its obligation as a PLR to its customers, PPL Electric has entered into certain contracts that meet the definition of a derivative. However, NPNS has been elected for these contracts. See Notes 16 and 17 for additional information on derivatives. Revenue (PPL) Operating Revenues For the years ended December 31, the Statements of Income "Operating Revenues" line item contains revenue from the following:
| 2017 |  | 2016 |  | 2015
Domestic electric and gas revenues (a) | $ | 5,351 |  |  | $ | 5,297 |  |  | $ | 5,239 |
U.K. operating revenues (b) | 2,091 |  |  | 2,207 |  |  | 2,410 |
Domestic - other | 5 |  |  | 13 |  |  | 20 |
Total | $ | 7,447 |  |  | $ | 7,517 |  |  | $ | 7,669 |
(a) | Represents revenues from cost-based rate-regulated generation, transmission and/or distribution in Pennsylvania, Kentucky, Virginia and Tennessee, including regulated wholesale revenue.
(b) | Primarily represents regulated electricity distribution revenues from the operation of WPD's distribution networks.
Revenue Recognition (All Registrants) Operating revenues are primarily recorded based on energy deliveries through the end of the calendar month. Unbilled retail revenues result because customers' bills are rendered throughout the month, rather than bills being rendered at the end of the month. For LKE, LG&E and KU, unbilled revenues for a month are calculated by multiplying an estimate of unbilled kWh by the estimated average cents per kWh. Any difference between estimated and actual revenues is adjusted the following month when the previous unbilled estimate is reversed and actual billings occur. For PPL Electric, unbilled revenues for a month are calculated by multiplying the actual unbilled kWh by an average rate per customer class. (PPL) WPD is currently operating under the eight-year price control period of RIIO-ED1, which commenced for electric distribution companies on April 1, 2015. Ofgem has adopted a price control mechanism that establishes the amount of base demand revenue WPD can earn, subject to certain true-ups, and provides for an increase or reduction in revenues based on incentives or penalties for performance relative to pre-established targets. WPD's allowed revenue primarily includes base demand revenue (adjusted for inflation using RPI), performance incentive revenues/penalties and adjustments for over or under-recovery from prior periods. As the regulatory model is incentive based rather than a cost recovery model, WPD is not subject to accounting for the effects of certain types of regulation as prescribed by GAAP. Therefore, the accounting treatment of adjustments to base demand revenue and/or allowed revenue is evaluated primarily based on revenue recognition accounting guidance. Unlike prior price control reviews, base demand revenue under RIIO-ED1 is adjusted during the price control period. The most significant of those adjustments are:
• | Inflation True-Up - The base demand revenue for the RIIO-ED1 period was set based on 2012/13 prices. Therefore an inflation factor as determined by forecasted RPI, provided by HM Treasury, is applied to base demand revenue.
Forecasted RPI is trued up to actuals and affects future base demand revenue two regulatory years later. This revenue change is called the "TRU" adjustment.
• | Annual Iteration Process (AIP) - The RIIO-ED1 price control period also includes an AIP. This will allow future base demand revenues agreed with the regulator as part of the price control review, to be updated during the price control period for financial adjustments including tax, pensions, cost of debt, legacy price control adjustments from preceding price control periods and adjustments relating to actual and allowed total expenditure together with the Totex Incentive Mechanism (TIM). Under the TIM, WPD's DNOs are able to retain 70% of any amounts not spent against the RIIO-ED1 plan and bear 70% of any over-spends. The AIP calculates an incremental change to base demand revenue, known as the "MOD" adjustment.
As both MOD and TRU are changes to future base demand revenues as determined by Ofgem, these adjustments are recognized as a component of revenues in future years in which service is provided and revenues are collected or returned to customers. In addition to base demand revenue, certain other items are added or subtracted to arrive at allowed revenue. The most significant of these are:
• | Incentives - Ofgem has established incentives to provide opportunities for DNO's to enhance overall returns by improving network efficiency, reliability and customer service. These incentives can result in an increase or reduction in revenues based on incentives or penalties for actual performance against pre-established targets based on past performance. The annual incentives and penalties are reflected in customers' rates on a two-year lag from the time they are earned and/or assessed. Incentive revenues and penalties are included in revenues when they are billed to customers.
• | Correction Factor - During the current price control period, WPD sets its tariffs to recover allowed revenue. However, in any fiscal period, WPD's revenue could be negatively affected if its tariffs and the volume delivered do not fully recover the revenue allowed for a particular period. Conversely, WPD could also over-recover revenue. Over and under-recoveries are subtracted from or added to allowed revenue in future years when they are billed to customers, known as the "Correction Factor" or "K-factor." Over and under-recovered amounts arising for the periods beginning with the 2014/15 regulatory year and refunded/recovered under RIIO-ED1 will be refunded/recovered on a two year lag (previously one year). Therefore the 2014/15 over/under-recovery adjustment occurred in the 2016/17 regulatory year.
Accounts Receivable (All Registrants) Accounts receivable are reported on the Balance Sheets at the gross outstanding amount adjusted for an allowance for doubtful accounts. Allowance for Doubtful Accounts Accounts receivable collectability is evaluated using a combination of factors, including past due status based on contractual terms, trends in write-offs and the age of the receivable. Specific events, such as bankruptcies, are also considered when applicable. Adjustments to the allowance for doubtful accounts are made when necessary based on the results of analysis, the aging of receivables and historical and industry trends. Accounts receivable are written off in the period in which the receivable is deemed uncollectible. The changes in the allowance for doubtful accounts were:
|  |  | Additions |  |  |  |
| Balance at Beginning of Period |  | Charged to Income |  | Charged to Other Accounts |  | Deductions (a) |  | Balance at End of Period
PPL |  |  |  |  |  |  |  |  |
2017 | $ | 54 |  |  | $ | 28 |  |  | $ | (1 | ) |  | $ | 30 |  |  | $ | 51 |
2016 | 41 |  |  | 44 |  |  | — |  |  | 31 |  |  | 54 |
2015 | 44 |  |  | 49 |  |  | (2 | ) |  | 50 |  |  | 41 |
PPL Electric |  |  |  |  |  |  |  |  |
2017 | $ | 28 |  |  | $ | 18 |  |  | $ | — |  |  | $ | 22 |  |  | $ | 24 |
2016 | 16 |  |  | 35 |  |  | — |  |  | 23 |  |  | 28 |
2015 | 17 |  |  | 39 |  |  | — |  |  | 40 |  |  | 16 |
|  |  | Additions |  |  |  |
| Balance at Beginning of Period |  | Charged to Income |  | Charged to Other Accounts |  | Deductions (a) |  | Balance at End of Period
LKE |  |  |  |  |  |  |  |  |
2017 | $ | 24 |  |  | $ | 8 |  |  | $ | (1 | ) |  | $ | 6 |  |  | $ | 25 |
2016 | 23 |  |  | 8 |  |  | — |  |  | 7 |  |  | 24 |
2015 | 25 |  |  | 9 |  |  | (2 | ) |  | 9 |  |  | 23 |
LG&E |  |  |  |  |  |  |  |  |
2017 | $ | 2 |  |  | $ | 2 |  |  | $ | (1 | ) |  | $ | 2 |  |  | $ | 1 |
2016 | 1 |  |  | 2 |  |  | 1 |  |  | 2 |  |  | 2 |
2015 | 2 |  |  | 2 |  |  | — |  |  | 3 |  |  | 1 |
KU |  |  |  |  |  |  |  |  |
2017 | $ | 2 |  |  | $ | 4 |  |  | $ | (1 | ) |  | $ | 4 |  |  | $ | 1 |
2016 | 2 |  |  | 4 |  |  | — |  |  | 4 |  |  | 2 |
2015 | 2 |  |  | 5 |  |  | — |  |  | 5 |  |  | 2 |
(a) | Primarily related to uncollectible accounts written off.
Cash (All Registrants) Cash Equivalents All highly liquid investments with original maturities of three months or less are considered to be cash equivalents. (PPL and PPL Electric) Restricted Cash and Cash Equivalents Bank deposits and other cash equivalents that are restricted by agreement or that have been clearly designated for a specific purpose are classified as restricted cash and cash equivalents. The change in restricted cash and cash equivalents is reported as an investing activity on the Statements of Cash Flows. On the Balance Sheets, the current portion of restricted cash and cash equivalents is included in "Other current assets," while the noncurrent portion is included in "Other noncurrent assets." At December 31, the balances of restricted cash and cash equivalents included the following:
| PPL |  | PPL Electric
| 2017 |  | 2016 |  | 2017 |  | 2016
Low carbon network fund (a) | $ | 17 |  |  | $ | 17 |  |  | $ | — |  |  | $ | — |
Other | 9 |  |  | 9 |  |  | 2 |  |  | 2 |
Total | $ | 26 |  |  | $ | 26 |  |  | $ | 2 |  |  | $ | 2 |
(a) | Funds received by WPD, which are to be spent on approved initiatives to support a low carbon environment.
(All Registrants) Fair Value Measurements The Registrants value certain financial and nonfinancial assets and liabilities at fair value. Generally, the most significant fair value measurements relate to price risk management assets and liabilities, investments in securities in defined benefit plans, and cash and cash equivalents. PPL and its subsidiaries use, as appropriate, a market approach (generally, data from market transactions), an income approach (generally, present value techniques and option-pricing models) and/or a cost approach (generally, replacement cost) to measure the fair value of an asset or liability. These valuation approaches incorporate inputs such as observable, independent market data and/or unobservable data that management believes are predicated on the assumptions market participants would use to price an asset or liability. These inputs may incorporate, as applicable, certain risks such as nonperformance risk, which includes credit risk. The Registrants classify fair value measurements within one of three levels in the fair value hierarchy. The level assigned to a fair value measurement is based on the lowest level input that is significant to the fair value measurement in its entirety. The three levels of the fair value hierarchy are as follows:
• | Level 1 - quoted prices (unadjusted) in active markets for identical assets or liabilities that are accessible at the measurement date. Active markets are those in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis.
• | Level 2 - inputs other than quoted prices included within Level 1 that are either directly or indirectly observable for substantially the full term of the asset or liability.
• | Level 3 - unobservable inputs that management believes are predicated on the assumptions market participants would use to measure the asset or liability at fair value.
Assessing the significance of a particular input requires judgment that considers factors specific to the asset or liability. As such, the Registrants' assessment of the significance of a particular input may affect how the assets and liabilities are classified within the fair value hierarchy. Investments (All Registrants) Generally, the original maturity date of an investment and management's intent and ability to sell an investment prior to its original maturity determine the classification of investments as either short-term or long-term. Investments that would otherwise be classified as short-term, but are restricted as to withdrawal or use for other than current operations or are clearly designated for expenditure in the acquisition or construction of noncurrent assets or for the liquidation of long-term debts, are classified as long-term. Short-term Investments Short-term investments generally include certain deposits as well as securities that are considered highly liquid or provide for periodic reset of interest rates. Investments with original maturities greater than three months and less than a year, as well as investments with original maturities of greater than a year that management has the ability and intent to sell within a year, are included in "Other current assets" on the Balance Sheets. (PPL, LKE, LG&E and KU) Cost Method Investment LG&E and KU each have an investment in OVEC, which is accounted for using the cost method. The investment is recorded in "Other noncurrent assets" on the PPL, LKE, LG&E and KU Balance Sheets. LG&E and KU and ten other electric utilities are equity owners of OVEC. OVEC's power is currently supplied to LG&E and KU and 11 other companies affiliated with the various owners. LG&E and KU own 5.63% and 2.5% of OVEC's common stock. Pursuant to a power purchase agreement, LG&E and KU are contractually entitled to their ownership percentage of OVEC's output, which is approximately 120 MW for LG&E and approximately 53 MW for KU. LG&E's and KU's combined investment in OVEC is not significant. The direct exposure to loss as a result of LG&E's and KU's involvement with OVEC is generally limited to the value of their investments; however, LG&E and KU are conditionally responsible for a pro-rata share of certain OVEC obligations, pursuant to their power purchase contract with OVEC. As part of PPL's acquisition of LKE, the value of the power purchase contract was recorded as an intangible asset with an offsetting regulatory liability, both of which are being amortized using the units-of-production method until March 2026. See Notes 6, 13 and 18 for additional discussion of the power purchase agreement. Long-Lived and Intangible Assets Property, Plant and Equipment (All Registrants) PP&E is recorded at original cost, unless impaired. PP&E acquired in business combinations is recorded at fair value at the time of acquisition. If impaired, the asset is written down to fair value at that time, which becomes the new cost basis of the asset. Original cost for constructed assets includes material, labor, contractor costs, certain overheads and financing costs, where applicable. The cost of repairs and minor replacements are charged to expense as incurred. The Registrants record costs associated with planned major maintenance projects in the period in which the costs are incurred. No costs associated with planned major maintenance projects are accrued to PP&E in advance of the period in which the work is performed. LG&E and KU accrue costs of removal net of estimated salvage value through depreciation, which is included in the calculation of customer rates over the assets' depreciable lives in accordance with regulatory practices. Cost of removal amounts accrued through depreciation rates are accumulated as a regulatory liability until the removal costs are incurred. For LKE, LG&E and KU, all ARO depreciation expenses are reclassified to a regulatory asset. See "Asset Retirement Obligations" below and Note 6 for additional information. PPL Electric records net costs of removal when incurred as a regulatory asset. The regulatory asset is subsequently amortized through depreciation over a five-year period, which is recoverable in customer rates in accordance with regulatory practices. AFUDC is capitalized at PPL Electric as part of the construction costs for cost-based rate-regulated projects for which a return on such costs is recovered after the project is placed in service. The debt component of AFUDC is credited to "Interest Expense" and the equity component is credited to "Other Income (Expense) - net" on the Statements of Income. LG&E and KU generally do not record AFUDC, except for certain instances in KU's FERC approved rates charged to its municipal customers, as a return is provided on construction work in progress. (PPL) PPL capitalizes interest costs as part of construction costs. Capitalized interest, including the debt component of AFUDC for PPL, was $11 million in 2017, 2016 and 2015. Depreciation (All Registrants) Depreciation is recorded over the estimated useful lives of property using various methods including the straight-line, composite and group methods. When a component of PP&E that was depreciated under the composite or group method is retired, the original cost is charged to accumulated depreciation. When all or a significant portion of an operating unit that was depreciated under the composite or group method is retired or sold, the property and the related accumulated depreciation account is reduced and any gain or loss is included in income, unless otherwise required by regulators. Following are the weighted-average annual rates of depreciation, for regulated utility plant, for the years ended December 31:
| 2017 |  | 2016 |  | 2015
PPL | 2.65 | % |  | 2.73 | % |  | 2.57 | %
PPL Electric | 2.86 | % |  | 2.63 | % |  | 2.46 | %
LKE | 3.64 | % |  | 3.69 | % |  | 3.69 | %
LG&E | 3.63 | % |  | 3.58 | % |  | 3.65 | %
KU | 3.66 | % |  | 3.77 | % |  | 3.71 | %
(All Registrants) Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price paid over the fair value of the identifiable net assets acquired in a business combination. Other acquired intangible assets are initially measured based on their fair value. Intangibles that have finite useful lives are amortized over their useful lives based upon the pattern in which the economic benefits of the intangible assets are consumed or otherwise used. Costs incurred to obtain an initial license and renew or extend terms of licenses are capitalized as intangible assets. When determining the useful life of an intangible asset, including intangible assets that are renewed or extended, PPL and its subsidiaries consider:
• | the expected use of the asset;
• | the expected useful life of other assets to which the useful life of the intangible asset may relate;
• | legal, regulatory, or contractual provisions that may limit the useful life;
• | the company's historical experience as evidence of its ability to support renewal or extension;
• | the effects of obsolescence, demand, competition, and other economic factors; and,
• | the level of maintenance expenditures required to obtain the expected future cash flows from the asset.
Asset Impairment (Excluding Investments) The Registrants review long-lived assets that are subject to depreciation or amortization, including finite-lived intangibles, for impairment when events or circumstances indicate carrying amounts may not be recoverable. A long-lived asset classified as held and used is impaired when the carrying amount of the asset exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. If impaired, the asset's carrying value is written down to its fair value. A long-lived asset classified as held for sale is impaired when the carrying amount of the asset (disposal group) exceeds its fair value less cost to sell. If impaired, the asset's (disposal group's) carrying value is written down to its fair value less cost to sell. PPL, LKE, LG&E and KU review goodwill for impairment at the reporting unit level annually or more frequently when events or circumstances indicate that the carrying amount of a reporting unit may be greater than the unit's fair value. Additionally, goodwill must be tested for impairment in circumstances when a portion of goodwill has been allocated to a business to be disposed. PPL's, LKE's, LG&E's and KU's reporting units are at the operating segment level. PPL, LKE, LG&E and KU may elect either to initially make a qualitative evaluation about the likelihood of an impairment of goodwill or to bypass the qualitative evaluation and test goodwill for impairment using a two-step quantitative test. If the qualitative evaluation (referred to as "step zero") is elected and the assessment results in a determination that it is not more likely than not that the fair value of a reporting unit is less than the carrying amount, the two-step quantitative impairment test is not necessary. However, the quantitative impairment test is required if management concludes it is more likely than not that the fair value of a reporting unit is less than the carrying amount based on the step zero assessment. If the carrying amount of the reporting unit, including goodwill, exceeds its fair value, the implied fair value of goodwill must be calculated in the same manner as goodwill in a business combination. The fair value of a reporting unit is allocated to all assets and liabilities of that unit as if the reporting unit had been acquired in a business combination. The excess of the fair value of the reporting unit over the amounts assigned to its assets and liabilities is the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount, goodwill is written down to its implied fair value. PPL (for its U.K. Regulated and Kentucky Regulated segments), and individually, LKE, LG&E and KU elected to perform the qualitative step zero evaluation of goodwill as of October 1, 2017. These evaluations considered the excess of fair value over the carrying value of each reporting unit that was calculated during step one of the quantitative impairment tests performed in the fourth quarter of 2015, and the relevant events and circumstances that occurred since those tests were performed including:
• | current year financial performance versus the prior year;
• | changes in planned capital expenditures;
• | the consistency of forecasted free cash flows;
• | earnings quality and sustainability;
• | changes in market participant discount rates;
• | changes in long-term growth rates
• | changes in PPL's market capitalization; and,
• | the overall economic and regulatory environments in which these regulated entities operate.
Based on these evaluations, management concluded it was not more likely than not that the fair value of these reporting units was less than their carrying value. As such, the two-step quantitative impairment test was not performed and no impairment was recognized. (PPL, LKE, LG&E and KU) Asset Retirement Obligations PPL and its subsidiaries record liabilities to reflect various legal obligations associated with the retirement of long-lived assets. Initially, this obligation is measured at fair value and offset with an increase in the value of the capitalized asset, which is depreciated over the asset's useful life. Until the obligation is settled, the liability is increased through the recognition of accretion expense classified within "Other operation and maintenance" on the Statements of Income to reflect changes in the obligation due to the passage of time. For LKE, LG&E and KU, all ARO accretion and depreciation expenses are reclassified as a regulatory asset. ARO regulatory assets associated with certain CCR projects are amortized to expense in accordance with regulatory approvals. For other AROs, at the time of retirement, the related ARO regulatory asset is offset against the associated cost of removal regulatory liability, PP&E and ARO liability. Estimated ARO costs and settlement dates, which affect the carrying value of the ARO and the related capitalized asset, are reviewed periodically to ensure that any material changes are incorporated into the latest estimate of the ARO. Any change to the capitalized asset, positive or negative, is generally amortized over the remaining life of the associated long-lived asset. See Note 6 and Note 19 for additional information on AROs. Compensation and Benefits Defined Benefits (All Registrants) Certain PPL subsidiaries sponsor various defined benefit pension and other postretirement plans. An asset or liability is recorded to recognize the funded status of all defined benefit plans with an offsetting entry to AOCI or, for LG&E, KU and PPL Electric, to regulatory assets or liabilities. Consequently, the funded status of all defined benefit plans is fully recognized on the Balance Sheets. The expected return on plan assets is determined based on a market-related value of plan assets, which is calculated by rolling forward the prior year market-related value with contributions, disbursements and long-term expected return on investments. One-fifth of the difference between the actual value and the expected value is added (or subtracted if negative) to the expected value to determine the new market-related value. PPL uses an accelerated amortization method for the recognition of gains and losses for its defined benefit pension plans. Under the accelerated method, actuarial gains and losses in excess of 30% of the plan's projected benefit obligation are amortized on a straight-line basis over one-half of the expected average remaining service of active plan participants. Actuarial gains and losses in excess of 10% of the greater of the plan's projected benefit obligation or the market-related value of plan assets and less than 30% of the plan's projected benefit obligation are amortized on a straight-line basis over the expected average remaining service period of active plan participants. See Note 6 for a discussion of the regulatory treatment of defined benefit costs and Note 11 for a discussion of defined benefits. Discount Rate Change for U.K. Pension Plans (PPL) In selecting the discount rate for its U.K. pension plans, WPD historically used a single weighted-average discount rate in the calculation of net periodic defined benefit cost. WPD began using individual spot rates to measure service cost and interest cost for the calculation of net periodic defined benefit cost in 2016. In 2016, this change in discount rate resulted in lower net periodic defined benefit costs recognized on PPL's Statement of Income of $43 million ($34 million after-tax or $0.05 per share). See Note 11 for additional information. Stock-Based Compensation (PPL, PPL Electric and LKE) PPL has several stock-based compensation plans for purposes of granting stock options, restricted stock, restricted stock units and performance units to certain employees as well as stock units and restricted stock units to directors. PPL grants most stock-based awards in the first quarter of each year. PPL and its subsidiaries recognize compensation expense for stock-based awards based on the fair value method. Forfeitures of awards are recognized when they occur. See Note 10 for a discussion of stock-based compensation. All awards are recorded as equity or a liability on the Balance Sheets. Stock-based compensation is primarily included in "Other operation and maintenance" on the Statements of Income. Stock-based compensation expense for PPL Electric and LKE includes an allocation of PPL Services' expense. Taxes Income Taxes (All Registrants) PPL and its domestic subsidiaries file a consolidated U.S. federal income tax return. The Registrants have completed or made reasonable estimates of the effects of the TCJA and reflected these amounts in their December 31, 2017 financial statements. The Registrants continue to evaluate the application of the TCJA and have used significant management judgment to make certain assumptions concerning the application of various components of the law in the calculation of 2017 income tax expense. The current and deferred components of the income tax expense calculations that the Registrants consider provisional due to uncertainty either with respect to the technical application of the law or the quantification of the impact of the law include (but are not limited to): tax depreciation, deductible executive compensation, and the accumulated foreign earnings used to calculate the deemed dividend included in PPL's taxable income in 2017 along with the impact of associated foreign tax credits and related valuation allowances. The Registrants believe that classification of these items as provisional is appropriate. The Registrants have accounted for these items based on their interpretation of the TCJA. Further interpretive guidance on the TCJA from the IRS, Treasury, the Joint Committee on Taxation through its "Blue Book" or from Congress in the form of Technical Corrections may differ from the Registrants' interpretation of the TCJA. Significant management judgment is also required in developing the Registrants' provision for income taxes, primarily due to the uncertainty related to tax positions taken or expected to be taken in tax returns, valuation allowances on deferred tax assets and whether the undistributed earnings of WPD are considered indefinitely reinvested. Significant management judgment is also required to determine the amount of benefit to be recognized in relation to an uncertain tax position. The Registrants use a two-step process to evaluate tax positions. The first step requires an entity to determine whether, based on the technical merits supporting a particular tax position, it is more likely than not (greater than a 50% chance) that the tax position will be sustained. This determination assumes that the relevant taxing authority will examine the tax position and is aware of all the relevant facts surrounding the tax position. The second step requires an entity to recognize in the financial statements the benefit of a tax position that meets the more-likely-than-not recognition criterion. The benefit recognized is measured at the largest amount of benefit that has a likelihood of realization, upon settlement, that exceeds 50%. The amounts ultimately paid upon resolution of issues raised by taxing authorities may differ materially from the amounts accrued and may materially impact the financial statements of the Registrants in future periods. Deferred income taxes reflect the net future tax effects of temporary differences between the carrying amounts of assets and liabilities for accounting purposes and their basis for income tax purposes, as well as the tax effects of net operating losses and tax credit carryforwards. The Registrants record valuation allowances to reduce deferred tax assets to the amounts that are more likely than not to be realized. The Registrants consider the reversal of temporary differences, future taxable income and ongoing prudent and feasible tax planning strategies in initially recording and subsequently reevaluating the need for valuation allowances. If the Registrants determine that they are able to realize deferred tax assets in the future in excess of recorded net deferred tax assets, adjustments to the valuation allowances increase income by reducing tax expense in the period that such determination is made. Likewise, if the Registrants determine that they are not able to realize all or part of net deferred tax assets in the future, adjustments to the valuation allowances would decrease income by increasing tax expense in the period that such determination is made. The Registrants defer investment tax credits when the credits are utilized and amortize the deferred amounts over the average lives of the related assets. The Registrants recognize interest and penalties in "Income Taxes" on their Statements of Income. See Note 5 for additional discussion regarding income taxes, including the impact of the TCJA and management's conclusion that the undistributed earnings of WPD are considered indefinitely reinvested. The provision for PPL's, PPL Electric's, LKE's, LG&E's and KU's deferred income taxes for regulatory assets and liabilities is based upon the ratemaking principles reflected in rates established by the regulators. The difference in the provision for deferred income taxes for regulatory assets and liabilities and the amount that otherwise would be recorded under GAAP is deferred and included on the Balance Sheets in noncurrent "Regulatory assets" or "Regulatory liabilities." (PPL Electric, LKE, LG&E and KU) The income tax provision for PPL Electric, LG&E and KU is calculated in accordance with an intercompany tax sharing agreement, which provides that taxable income be calculated as if PPL Electric, LG&E, KU and any domestic subsidiaries each filed a separate return. Tax benefits are not shared between companies. The entity that generates a tax benefit is the entity that is entitled to the tax benefit. The effect of PPL filing a consolidated tax return is taken into account in the settlement of current taxes and the recognition of deferred taxes. At December 31, the following intercompany tax receivables (payables) were recorded:
| 2017 |  | 2016
PPL Electric | $ | 61 |  |  | $ | 13 |
LKE | (23 | ) |  | 1 |
LG&E | — |  |  | (18 | )
KU | — |  |  | (29 | )
Taxes, Other Than Income (All Registrants) The Registrants present sales taxes in "Other current liabilities" and PPL presents value-added taxes in "Taxes" on the Balance Sheets. These taxes are not reflected on the Statements of Income. See Note 5 for details on taxes included in "Taxes, other than income" on the Statements of Income. Other (All Registrants) Leases The Registrants evaluate whether arrangements entered into contain leases for accounting purposes. See Note 9 for additional information. Fuel, Materials and Supplies Fuel, natural gas stored underground and materials and supplies are valued using the average cost method. Fuel costs for electric generation are charged to expense as used. For LG&E, natural gas supply costs are charged to expense as delivered to the distribution system. See Note 6 for further discussion of the fuel adjustment clause and gas supply clause. (PPL, LKE, LG&E and KU) "Fuel, materials and supplies" on the Balance Sheets consisted of the following at December 31:
| PPL |  | LKE |  | LG&E |  | KU
| 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016
Fuel | $ | 107 |  |  | $ | 158 |  |  | $ | 107 |  |  | $ | 158 |  |  | $ | 45 |  |  | $ | 60 |  |  | $ | 62 |  |  | $ | 98 |
Natural gas stored underground | 43 |  |  | 42 |  |  | 43 |  |  | 42 |  |  | 43 |  |  | 42 |  |  | — |  |  | — |
Materials and supplies | 170 |  |  | 156 |  |  | 104 |  |  | 97 |  |  | 43 |  |  | 41 |  |  | 61 |  |  | 56 |
Total | $ | 320 |  |  | $ | 356 |  |  | $ | 254 |  |  | $ | 297 |  |  | $ | 131 |  |  | $ | 143 |  |  | $ | 123 |  |  | $ | 154 |
Guarantees (All Registrants) Generally, the initial measurement of a guarantee liability is the fair value of the guarantee at its inception. However, there are certain guarantees excluded from the scope of accounting guidance and other guarantees that are not subject to the initial recognition and measurement provisions of accounting guidance that only require disclosure. See Note 13 for further discussion of recorded and unrecorded guarantees. Treasury Stock (PPL) PPL restores all shares of common stock acquired to authorized but unissued shares of common stock upon acquisition. Foreign Currency Translation and Transactions (PPL) WPD's functional currency is the GBP, which is the local currency in the U.K. As such, assets and liabilities are translated to U.S. dollars at the exchange rates on the date of consolidation and related revenues and expenses are generally translated at average exchange rates prevailing during the period included in PPL's results of operations. Adjustments resulting from foreign currency translation are recorded in AOCI. Gains or losses relating to foreign currency transactions are recognized in "Other Income (Expense) - net" on the Statements of Income. See Note 15 for additional information.

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