Significant Accounting Policies | Significant Accounting Policies Organization – We are a global security and aerospace company principally engaged in the research, design, development, manufacture, integration and sustainment of advanced technology systems, products and services. We also provide a broad range of management, engineering, technical, scientific, logistics, system integration and cybersecurity services. We serve both U.S. and international customers with products and services that have defense, civil and commercial applications, with our principal customers being agencies of the U.S. Government. Basis of presentation – Our consolidated financial statements include the accounts of subsidiaries we control and variable interest entities if we are the primary beneficiary. We eliminate intercompany balances and transactions in consolidation. Our receivables, inventories, customer advances and amounts in excess of costs incurred and certain amounts in other current liabilities primarily are attributable to long-term contracts or programs in progress for which the related operating cycles are longer than one year. In accordance with industry practice, we include these items in current assets and current liabilities. Unless otherwise noted, we present all per share amounts cited in these consolidated financial statements on a “per diluted share” basis. Certain prior period amounts have been reclassified to conform with current year presentation. The discussion and presentation of the operating results of our business segments have been impacted by the following recent events. During the fourth quarter of 2017, the business segment formally known as Space Systems was renamed Space. There was no change to the composition of the portfolio in connection with the name change. The information for this segment for all periods included in these consolidated financial statements has been labeled using the new name. On August 16, 2016, we completed the divestiture of the Information Systems & Global Solutions (IS&GS) business, which merged with a subsidiary of Leidos Holdings, Inc. (Leidos) in a Reverse Morris Trust transaction. Accordingly, the operating results of the IS&GS business have been classified as discontinued operations on our consolidated statements of earnings for all prior periods presented. However, the cash flows of the IS&GS business have not been reclassified in our consolidated statements of cash flows as we retained the cash as part of the Transaction. See “ Note 3 – Acquisitions and Divestitures ” for additional information about the divestiture of the IS&GS business. On August 24, 2016, we increased our ownership interest in the AWE Management Limited (AWE) joint venture, which operates the United Kingdom’s nuclear deterrent program, from 33% to 51% . At which time, we began consolidating AWE. Consequently, our operating results include 100% of AWE’s sales and 51% of its operating profit. Prior to increasing our ownership interest, we accounted for our investment in AWE using the equity method of accounting. Under the equity method, we recognized only 33% of AWE’s earnings or losses and no sales. Accordingly, prior to August 24, 2016, the date we obtained control, we recorded 33% of AWE’s net earnings in our operating results and subsequent to August 24, 2016, we recognized 100% of AWE’s sales and 51% of its operating profit. See “ Note 3 – Acquisitions and Divestitures ” for additional information about the change in ownership of AWE. On November 6, 2015, we completed the acquisition of Sikorsky Aircraft Corporation and certain affiliated companies (collectively “Sikorsky”) for $9.0 billion , net of cash acquired, and aligned Sikorsky under our Rotary and Mission Systems (RMS) business segment. The operating results and cash flows of Sikorsky have been included on our consolidated statements of earnings and consolidated statements of cash flows since the November 6, 2015 acquisition date. Additionally, the assets and liabilities of Sikorsky are included in our consolidated balance sheets as of December 31, 2017 and December 31, 2016 . See “ Note 3 – Acquisitions and Divestitures ” for additional information about the acquisition of Sikorsky and related final purchase accounting. During the fourth quarter of 2015, we realigned certain programs among our business segments. The amounts, discussion and presentation of our business segments for all periods presented in these consolidated financial statements reflect the program realignment. Use of estimates – We prepare our consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP). In doing so, we are required to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. We base these estimates on historical experience and on various other assumptions that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying amounts of assets and liabilities that are not readily apparent from other sources. Our actual results may differ materially from these estimates. Significant estimates inherent in the preparation of our consolidated financial statements include, but are not limited to, accounting for sales and cost recognition, postretirement benefit plans, environmental receivables and liabilities, evaluation of goodwill and other assets for impairment, income taxes including deferred tax assets, fair value measurements and contingencies. Sales and earnings – We record net sales and estimated profits for substantially all of our contracts using the percentage-of-completion method for fixed-price and cost-reimbursable contracts for products and services with the U.S. Government. Sales are recorded on all time-and-materials contracts as the work is performed based on agreed-upon hourly rates and allowable costs. We account for our services contracts with non-U.S. Government customers using the services method of accounting. We classify net sales as products or services on our consolidated statements of earnings based on the attributes of the underlying contracts. Percentage-of-Completion Method – The percentage-of-completion method for product contracts depends on the nature of the products provided under the contract. For example, for contracts that require us to perform a significant level of development effort in comparison to the total value of the contract and/or to deliver minimal quantities, sales are recorded using the cost-to-cost method to measure progress toward completion. Under the cost-to-cost method of accounting, we recognize sales and an estimated profit as costs are incurred based on the proportion that the incurred costs bear to total estimated costs. For contracts that require us to provide a substantial number of similar items without a significant level of development, we record sales and an estimated profit on a percentage-of-completion basis using units-of-delivery as the basis to measure progress toward completing the contract. For contracts to provide services to the U.S. Government, sales are generally recorded using the cost-to-cost method. Award and incentive fees, as well as penalties related to contract performance, are considered in estimating sales and profit rates on contracts accounted for under the percentage-of-completion method. Estimates of award fees are based on past experience and anticipated performance. We record incentives or penalties when there is sufficient information to assess anticipated contract performance. Incentive provisions that increase or decrease earnings based solely on a single significant event are not recognized until the event occurs. Accounting for contracts using the percentage-of-completion method requires judgment relative to assessing risks, estimating contract sales and costs (including estimating award and incentive fees and penalties related to performance) and making assumptions for schedule and technical issues. Due to the number of years it may take to complete many of our contracts and the scope and nature of the work required to be performed on those contracts, the estimation of total sales and costs at completion is complicated and subject to many variables and, accordingly, is subject to change. When adjustments in estimated total contract sales or estimated total costs are required, any changes from prior estimates are recognized in the current period for the inception-to-date effect of such changes. When estimates of total costs to be incurred on a contract exceed estimates of total sales to be earned, a provision for the entire loss on the contract is recorded in the period in which the loss is determined. Many of our contracts span several years and include highly complex technical requirements. At the outset of a contract, we identify and monitor risks to the achievement of the technical, schedule and cost aspects of the contract and assess the effects of those risks on our estimates of total costs to complete the contract. The estimates consider the technical requirements (e.g., a newly-developed product versus a mature product), the schedule and associated tasks (e.g., the number and type of milestone events) and costs (e.g., material, labor, subcontractor, overhead and the estimated costs to fulfill our industrial cooperation agreements, sometimes referred to as offset agreements, required under certain contracts with international customers). The initial profit booking rate of each contract considers risks surrounding the ability to achieve the technical requirements, schedule and costs in the initial estimated total costs to complete the contract. Profit booking rates may increase during the performance of the contract if we successfully retire risks surrounding the technical, schedule and cost aspects of the contract which decreases the estimated total costs to complete the contract. Conversely, our profit booking rates may decrease if the estimated total costs to complete the contract increase. All of the estimates are subject to change during the performance of the contract and may affect the profit booking rate. In addition, comparability of our business segment sales, operating profit and operating margins may be impacted by changes in profit booking rates on our contracts accounted for using the percentage-of-completion method of accounting. Increases in the profit booking rates, typically referred to as risk retirements, usually relate to revisions in the estimated total costs that reflect improved conditions on a particular contract. Conversely, conditions on a particular contract may deteriorate, resulting in an increase in the estimated total costs to complete and a reduction in the profit booking rate. Increases or decreases in profit booking rates are recognized in the current period and reflect the inception-to-date effect of such changes. Segment operating profit and margins may also be impacted favorably or unfavorably by other items. Favorable items may include the positive resolution of contractual matters, cost recoveries on restructuring charges, insurance recoveries and gains on sales of assets. Unfavorable items may include the adverse resolution of contractual matters; restructuring charges, except for significant severance actions (such as those mentioned below in “ Note 15 – Restructuring Charges ” ), which are excluded from segment operating results; reserves for disputes; asset impairments; and losses on sales of certain assets. Segment operating profit and items such as risk retirements, reductions of profit booking rates or other matters are presented net of state income taxes. Changes in Estimates – As previously disclosed, we have a program to design, integrate, and install an air missile defense C4I systems for an international customer that has experienced performance issues and for which we have periodically accrued reserves. In 2017, we revised our estimated costs to complete the program, EADGE-T, as a consequence of ongoing performance matters and recorded an additional charge of $120 million ( $74 million or $0.25 per share, after tax) at our RMS business segment. As of December 31, 2017, cumulative losses, including reserves, remained at approximately $260 million on this program. We are continuing to monitor the viability of the program and the available options and could record additional charges in future periods. However, based on the reserves already accrued and our current estimate of the costs to complete the program, at this time we do not anticipate that additional charges, if any, would be material. We have two commercial satellite programs at our Space business segment, for which we have experienced performance issues related to the development and integration of a modernized LM 2100 satellite platform. These commercial programs require the development of new satellite technology to enhance the LM 2100’s power, propulsion and electronics, among other items. The enhanced satellite is expected to benefit other commercial and government satellite programs. We have periodically revised our estimated costs to complete these developmental commercial programs. We have recorded cumulative losses of approximately $305 million as of December 31, 2017, including approximately $135 million ( $83 million or $0.29 per share, after tax) recorded during the year ended December 31, 2017. While these losses reflect our estimated total losses on the programs, we will continue to incur unrecovered costs each period until we complete these programs and may have to record additional loss reserves in future periods, which could be material to our operating results. While we do not currently anticipate recording additional loss reserves, the programs remain developmental and further challenges in the delivery and integration of new satellite technology, anomalies discovered during system testing requiring repair or rework, further schedule delays and potential penalties could require that we record additional reserves. We do not currently expect to be able to meet the delivery schedule under the contracts and have informed the customers. The customers could seek to exercise a termination right under the contracts, in which case we would have to refund the payments we have received and pay certain penalties. However, we think the probability that the customers will seek to exercise any termination right is remote as the delay beyond the termination date is modest and the customers have an immediate need for the satellites. Our consolidated net adjustments not related to volume, including net profit booking rate adjustments and other matters, net of state income taxes, increased segment operating profit by approximately $1.5 billion in both 2017 and 2016 and $1.7 billion in 2015 . These adjustments increased net earnings by approximately $980 million ( $3.37 per share) in 2017 , $950 million ( $3.13 per share) in 2016 and $1.1 billion ( $3.50 per share) in 2015 . Services Method – Under fixed-price service contracts, we are paid a predetermined fixed amount for a specified scope of work and generally have full responsibility for the costs associated with the contract and the resulting profit or loss. We record net sales under fixed-price service contracts with non-U.S. Government customers on a straight-line basis over the period of contract performance, unless evidence suggests that net sales are earned or the obligations are fulfilled in a different pattern. For cost-reimbursable contracts for services to non-U.S. Government customers, we record net sales as services are performed, except for award and incentive fees. Award and incentive fees are recorded when they are fixed or determinable, generally at the date the amount is communicated to us by the customer. This approach results in the recognition of such fees at contractual intervals (typically every six months) throughout the contract and is dependent on the customer’s processes for notification of awards and issuance of formal notifications. Costs for all service contracts are expensed as incurred. Research and development and similar costs – Except for certain arrangements described below, we account for independent research and development costs as part of the general and administrative costs that are allocated among all of our contracts and programs in progress under U.S. Government contractual arrangements and charged to cost of sales. Under certain arrangements in which a customer shares in product development costs, our portion of unreimbursed costs is expensed as incurred in cost of sales. Independent research and development costs charged to cost of sales totaled $1.2 billion in 2017 , $988 million in 2016 and $817 million in 2015 . Costs we incur under customer-sponsored research and development programs pursuant to contracts are included in net sales and cost of sales. Stock-based compensation – Compensation cost related to all share-based payments is measured at the grant date based on the estimated fair value of the award. We generally recognize the compensation cost ratably over a three-year vesting period, net of estimated forfeitures. At each reporting date, the number of shares is adjusted to the number ultimately expected to vest. Income taxes – We calculate our provision for income taxes using the asset and liability method, under which deferred tax assets and liabilities are recognized based on the future tax consequences attributable to temporary differences that exist between the financial statement carrying amount of assets and liabilities and their respective tax bases, as well as from operating loss and tax credit carry-forwards. We measure deferred tax assets and liabilities using enacted tax rates that will apply in the years in which we expect the temporary differences to be recovered or paid. We periodically assess our tax exposures related to periods that are open to examination. Based on the latest available information, we evaluate our tax positions to determine whether the position will more likely than not be sustained upon examination by the Internal Revenue Service (IRS) or other taxing authorities. If we cannot reach a more-likely-than-not determination, no benefit is recorded. If we determine that the tax position is more likely than not to be sustained, we record the largest amount of benefit that is more likely than not to be realized when the tax position is settled. We record interest and penalties related to income taxes as a component of income tax expense on our consolidated statements of earnings. Interest and penalties were not material. Cash and cash equivalents – Cash equivalents include highly liquid instruments with original maturities of 90 days or less. Receivables – Receivables include amounts billed and currently due from customers and unbilled costs and accrued profits primarily related to sales on long-term contracts that have been recognized but not yet billed to customers. Pursuant to contract provisions, agencies of the U.S. Government and certain other customers have title to, or a security interest in, assets related to such contracts as a result of advances, performance-based payments and progress payments. We reflect those advances and payments as an offset to the related receivables balance for contracts that we account for on a percentage-of-completion basis using the cost-to-cost method to measure progress towards completion. On occasion, our customers may seek deferred payment terms to purchase our products. In connection with these transactions, we may, at our customer’s request, enter into arrangements for the non-recourse sale of customer receivables to unrelated third–party financial institutions. For accounting purposes, these transactions are not discounted and are treated as a sale of receivables as we have no continuing involvement. The sale proceeds from the financial institutions are reflected in our operating cash flows on the statement of cash flows. During 2017 , we sold approximately $698 million of customer receivables. There were no gains or losses related to sales of these receivables. Inventories – We record inventories at the lower of cost or estimated net realizable value. Costs on long-term contracts and programs in progress represent recoverable costs incurred for production or contract-specific facilities and equipment, allocable operating overhead, advances to suppliers and, in the case of contracts with the U.S. Government and substantially all other governments, research and development and general and administrative expenses. Pursuant to contract provisions, agencies of the U.S. Government and certain other customers have title to, or a security interest in, inventories related to such contracts as a result of advances, performance-based payments and progress payments. We reflect those advances and payments as an offset against the related inventory balances for contracts that we account for on a percentage-of-completion basis using units-of-delivery as the basis to measure progress toward completing the contract. We determine the costs of other product and supply inventories by the first-in first-out or average cost methods. Property, plant and equipment – We record property, plant and equipment at cost. We provide for depreciation and amortization on plant and equipment generally using accelerated methods during the first half of the estimated useful lives of the assets and the straight-line method thereafter. The estimated useful lives of our plant and equipment generally range from 10 to 40 years for buildings and five to 15 years for machinery and equipment. No depreciation expense is recorded on construction in progress until such assets are placed into operation. Depreciation expense related to plant and equipment was $760 million in 2017 , $747 million in 2016 , and $716 million in 2015 . We review the carrying amounts of long-lived assets for impairment if events or changes in the facts and circumstances indicate that their carrying amounts may not be recoverable. We assess impairment by comparing the estimated undiscounted future cash flows of the related asset grouping to its carrying amount. If an asset is determined to be impaired, we recognize an impairment charge in the current period for the difference between the fair value of the asset and its carrying amount. Capitalized software – We capitalize certain costs associated with the development or purchase of internal-use software. The amounts capitalized are included in other noncurrent assets on our consolidated balance sheets and are amortized on a straight-line basis over the estimated useful life of the resulting software, which ranges from two to six years. As of December 31, 2017 and 2016 , capitalized software totaled $424 million and $427 million , net of accumulated amortization of $2.0 billion and $1.9 billion . No amortization expense is recorded until the software is ready for its intended use. Amortization expense related to capitalized software was $123 million in 2017 , $136 million in 2016 and $161 million in 2015 . Goodwill – The assets and liabilities of acquired businesses are recorded under the acquisition method of accounting at their estimated fair values at the date of acquisition. Goodwill represents costs in excess of fair values assigned to the underlying identifiable net assets of acquired businesses. Our goodwill balance was $10.8 billion at both December 31, 2017 and 2016 . We perform an impairment test of our goodwill at least annually in the fourth quarter or more frequently whenever events or changes in circumstances indicate the carrying value of goodwill may be impaired. Such events or changes in circumstances may include a significant deterioration in overall economic conditions, changes in the business climate of our industry, a decline in our market capitalization, operating performance indicators, competition, reorganizations of our business, U.S. Government budget restrictions or the disposal of all or a portion of a reporting unit. Our goodwill has been allocated to and is tested for impairment at a level referred to as the reporting unit, which is our business segment level or a level below the business segment. The level at which we test goodwill for impairment requires us to determine whether the operations below the business segment constitute a self-sustaining business for which discrete financial information is available and segment management regularly reviews the operating results. We may use either a qualitative or quantitative approach when testing a reporting unit’s goodwill for impairment. For selected reporting units where we use the qualitative approach, we perform a qualitative evaluation of events and circumstances impacting the reporting unit to determine the likelihood of goodwill impairment. Based on that qualitative evaluation, if we determine it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, no further evaluation is necessary. Otherwise we perform a quantitative impairment test. We perform quantitative tests for most reporting units at least once every three years. However, for certain reporting units we may perform a quantitative impairment test every year. For the quantitative impairment test we compare the fair value of a reporting unit to its carrying value, including goodwill. If the fair value of a reporting unit exceeds its carrying value, goodwill of the reporting unit is not impaired. If the carrying value of the reporting unit, including goodwill, exceeds its fair value, a goodwill impairment loss is recognized in an amount equal to that excess. We generally estimate the fair value of each reporting unit using a combination of a discounted cash flow (DCF) analysis and market-based valuation methodologies such as comparable public company trading values and values observed in recent business acquisitions. Determining fair value requires the exercise of significant judgments, including the amount and timing of expected future cash flows, long-term growth rates, discount rates and relevant comparable public company earnings multiples and relevant transaction multiples. The cash flows employed in the DCF analysis are based on our best estimate of future sales, earnings and cash flows after considering factors such as general market conditions, U.S. Government budgets, existing firm orders, expected future orders, contracts with suppliers, labor agreements, changes in working capital, long term business plans and recent operating performance. The discount rates utilized in the DCF analysis are based on the respective reporting unit’s weighted average cost of capital, which takes into account the relative weights of each component of capital structure (equity and debt) and represents the expected cost of new capital, adjusted as appropriate to consider the risk inherent in future cash flows of the respective reporting unit. The carrying value of each reporting unit includes the assets and liabilities employed in its operations, goodwill and allocations of amounts held at the business segment and corporate levels. During the fourth quarters of 2017 and 2016 , we performed our annual goodwill impairment test for each of our reporting units. The results of our annual impairment tests of goodwill indicated that no impairment existed. During the fourth quarter of 2017, we realigned certain programs within the RMS business segment to align with changes in management structure. We performed goodwill impairment tests prior and subsequent to the realignment, and there was no indication of goodwill impairment. During the fourth quarter of 2015, we performed our annual goodwill impairment test for each of our reporting units. During the fourth quarter of 2015, we realigned certain programs between our business segments in connection with our strategic review of our government IT and technical services businesses. As part of the realignment, goodwill was reallocated between affected reporting units on a relative fair value basis. We performed goodwill impairment tests prior and subsequent to the realignment. The results of our 2015 annual impairment tests of goodwill indicated that no impairment existed. Intangible assets – Intangible assets from acquired businesses are recognized at their estimated fair values at the date of acquisition and consist of customer programs, trademarks, customer relationships, technology and other intangible assets. Customer programs include values assigned to major programs of acquired businesses and represent the aggregate value associated with the customer relationships, contracts, technology and trademarks underlying the associated program and are amortized on a straight-line basis over a period of expected cash flows used to measure the fair value, which ranges from nine to 20 years. Acquired intangibles deemed to have indefinite lives are not amortized, but are subject to annual impairment testing. This testing compares carrying value to fair value and, when appropriate, the carrying value of these assets is reduced to fair value. Finite-lived intangibles are amortized to expense over the applicable useful lives, ranging from three to 20 years, based on the nature of the asset and the underlying pattern of economic benefit as reflected by future net cash inflows. We perform an impairment test of finite-lived intangibles whenever events or changes in circumstances indicate their carrying value may be impaired. Customer advances and amounts in excess of cost incurred – We receive advances, performance-based payments and progress payments from customers that may exceed costs incurred on certain contracts, including contracts with agencies of the U.S. Government. We classify such advances, other than those reflected as a reduction of receivables or inventories as discussed above, as current liabilities. Postretirement benefit plans – Many of our employees are covered by defined benefit pension plans and we provide certain health care and life insurance benefits to eligible retirees (collectively, postretirement benefit plans). GAAP requires that the amounts we record related to our postretirement benefit plans be computed, based on service to date, using actuarial valuations that are based in part on certain key economic assumptions we make, including the discount rate, the expected long-term rate of return on plan assets and other actuarial assumptions including participant longevity (also known as mortality), health care cost trend rates and employee turnover, each as appropriate based on the nature of the plans. A market-related value of our plan assets, determined using actual asset gains or losses over the prior three year period, is used to calculate the amount of deferred asset gains or losses to be amortized. These asset gains or losses, along with those resulting from adjustments to our benefit obligation, will be amortized to expense using the corridor method, where gains and losses are recognized to the extent they exceed 10% of the greater of plan assets or benefit obligations, over the average future service period of employees expected to receive benefits under the plans of approximately nine years as of December 31, 2017 . This amortization period is expected to extend (approximately double) in 2020 when our non-union pension plan is frozen to use the average remaining life expectancy of the participants instead of average future service. We recognize on a plan-by-plan basis the funded status of our postretirement benefit plans under GAAP as either an asset recorded within other noncurrent assets or a liability recorded within noncurrent liabilities on our consolidated balance sheets. The GAAP funded status is measured as the difference between the fair value of the plan’s assets and the benefit obligation of the plan. The funded status under the Employee Retirement Income Security Act of 1974 (ERISA), as amended by the Pension Protection Act of 2006 (PPA), is calculated on a different basis than under GAAP. Environmental matters – We record a liability for environmental matters when it is probable that a liability has been incurred and the amount can be reasonably estimated. The amount of liability recorded is based on our estimate of the costs to be incurred for remediation at a particular site. We do not discount the recorded liabilities, as the amount and timing of future cash payments are not fixed or cannot be reliably determined. Our environmental liabilities are recorded on our consolidated balance sheets within other liabilities, both current |