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Summary Of Significant Accounting Policies (Policies)
12 Months Ended
Dec. 31, 2017
Accounting Policies [Abstract]  
Organization
Organization. General Dynamics is organized into four business groups: Aerospace, which delivers Gulfstream aircraft and provides services for Gulfstream aircraft and aircraft produced by other original equipment manufacturers (OEMs); Combat Systems, which designs and manufactures combat vehicles, weapons systems and munitions; Information Systems and Technology, which provides C4ISR (command, control, communication, computers, intelligence, surveillance and reconnaissance) solutions and information technology (IT) services; and Marine Systems, which designs, constructs and repairs surface ships and submarines. Our primary customer is the U.S. government. We also do significant business with non-U.S. governments and a diverse base of corporate and individual buyers of business aircraft.
Basis of Consolidation and Classification
Basis of Consolidation and Classification. The Consolidated Financial Statements include the accounts of General Dynamics Corporation and our wholly owned and majority-owned subsidiaries. We eliminate all inter-company balances and transactions in the Consolidated Financial Statements. Some prior-year amounts have been reclassified among financial statement accounts or disclosures to conform to the current-year presentation.
Consistent with industry practice, we classify assets and liabilities related to long-term contracts as current, even though some of these amounts may not be realized within one year.
Further discussion of our significant accounting policies is contained in the other notes to these financial statements.
Use of Estimates
Use of Estimates. The nature of our business requires that we make estimates and assumptions in accordance with U.S. generally accepted accounting principles (GAAP). These estimates and assumptions affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported amounts of revenue and expenses during the reporting period. We base our estimates on historical experience, currently available information and various other assumptions that we believe are reasonable under the circumstances. Actual results could differ from these estimates.
Discontinued Operations
Discontinued Operations, Net of Tax. In 2013, we settled litigation with the U.S. Navy related to the terminated A-12 aircraft contract in the company’s former tactical military aircraft business. In connection with the settlement, we released some rights to reimbursement of costs on ships under contract at our Bath, Maine, shipyard. As we progressed through the shipbuilding process, we determined that the cost associated with this settlement was greater than anticipated. Therefore, in 2016, we recognized an $84 loss, net of tax, to adjust the previously-recognized settlement value. In addition, we recognized a $10 loss, net of tax, in 2016 related to an environmental matter associated with a former operation of the company.
In 2015, we completed the sale of our axle business in the Combat Systems group. In 2016, we recognized a final adjustment of $13 to the loss on the sale of this business.
Research and Development Expenses
Research and Development Expenses. Company-sponsored research and development (R&D) expenses, including product development costs, were $521 in 2017, $418 in 2016 and $395 in 2015. The increase in 2017 is due primarily to higher R&D expenses in the Aerospace group associated with ongoing product-development efforts as the group progresses with the certification of its two newest aircraft models, the G500 and G600. R&D expenses are included in operating costs and expenses in the Consolidated Statement of Earnings in the period in which they are incurred. Customer-sponsored R&D expenses are charged directly to the related contracts.
The Aerospace group has cost-sharing arrangements with some of its suppliers that enhance the group’s internal development capabilities and offset a portion of the financial cost associated with the group’s product development efforts. These arrangements explicitly state that supplier contributions are for reimbursements of costs we incur in the development of new aircraft models and technologies, and we retain substantial rights in the products developed under these arrangements. We record amounts received from these cost-sharing arrangements as a reduction of R&D expenses. We have no obligation to refund any amounts received under the agreements regardless of the outcome of the development efforts. Under the typical terms of an agreement, payments received from suppliers for their share of the costs are based on milestones and are recognized as received. Our policy is to defer payments in excess of the costs we have incurred.
Interest, Net
Interest, Net. Net interest expense consisted of the following:
Year Ended December 31
2017
 
2016
 
2015
Interest expense
$
117

 
$
99

 
$
98

Interest income
(14
)
 
(8
)
 
(15
)
Interest expense, net
$
103

 
$
91

 
$
83


Cash And Equivalents And Investments In Debt And Equity Securities
Cash and Equivalents and Investments in Debt and Equity Securities. We consider securities with a maturity of three months or less to be cash equivalents. Our cash balances are invested primarily in time deposits rated A-/A3 or higher. Our investments in other securities are included in other current and noncurrent assets on the Consolidated Balance Sheet (see Note E). We report our held-to-maturity securities at amortized cost. We report our available-for-sale securities at fair value. Changes in the fair value of available-for-sale securities are recognized as a component of other comprehensive income (loss) in the Consolidated Statement of Comprehensive Income. We had no trading securities on December 31, 2017 or 2016.
Cash flows in 2016 and 2015 were affected negatively by growth in operating working capital in our Combat Systems group due to the utilization of deposits and the timing of billings on a large contract for a Middle Eastern customer, and in our Aerospace group from the build-up of inventory related to the new G500 and G600 aircraft programs and the liquidation of customer deposits associated with aircraft deliveries. In 2017, the growth in operating working capital due to these factors slowed and was offset by lower income tax payments.
Other Contract Costs
Other Contract Costs. Other contract costs represent amounts that are not currently allocable to government contracts, such as a portion of our estimated workers’ compensation obligations, other insurance-related assessments, pension and other post-retirement benefits, and environmental expenses. These costs will become allocable to contracts generally after they are paid. We expect to recover these costs through ongoing business, including existing backlog and probable follow-on contracts. If the backlog in the future does not support the continued deferral of these costs, the profitability of our remaining contracts could be adversely affected.
Long-lived Assets and Goodwill
Long-lived Assets and Goodwill. We review long-lived assets, including intangible assets subject to amortization, for impairment whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. We assess the recoverability of the carrying value of assets held for use based on a review of undiscounted projected cash flows. Impairment losses, where identified, are measured as the excess of the carrying value of the long-lived asset over its estimated fair value as determined by discounted projected cash flows.
We review goodwill for impairment annually or when circumstances indicate that an impairment is more likely than not. Goodwill represents the purchase price paid in excess of the fair value of net tangible and intangible assets acquired. The test for goodwill impairment is a two-step process to first identify potential goodwill impairment for each reporting unit and then, if necessary, measure the amount of the impairment loss. Our reporting units are consistent with our business groups in Note R. We completed the required annual goodwill impairment test as of December 31, 2017. The first step of the goodwill impairment test compares the fair value of each of our reporting units to its carrying value. We estimate the fair value of our reporting units based primarily on the discounted projected cash flows of the underlying operations. The estimated fair value of each of our reporting units was well in excess of its respective carrying value as of December 31, 2017.
Accounting Standards Updates
Accounting Standards Updates. On January 1, 2017, we retrospectively adopted the following accounting standards issued by the Financial Accounting Standards Board (FASB) that impacted our prior-period financial statements:
 
ASC Topic 606, Revenue from Contracts with Customers
 
ASU 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes
See Note T for further discussion of each of these accounting standards.
We also adopted ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory, on January 1, 2017. We recognized the cumulative effect of this standard as a $3 decrease to retained earnings on the date of adoption. ASU 2016-16 requires recognition of the current and deferred income tax effects of an intra-entity asset transfer, other than inventory, when the transfer occurs, as opposed to former GAAP, which required companies to defer the income tax effects of intra-entity asset transfers until the asset was sold to an outside party. The income tax effects of intra-entity inventory transfers will continue to be deferred until the inventory is sold.
There are several new accounting standards that have been issued by the FASB but are not effective until after December 31, 2017, including the following:
ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. ASU 2016-01 addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. Specific to our business, ASU 2016-01 requires equity investments to be measured at fair value with changes in fair value recognized in net income. The ASU eliminates the available-for-sale classification for equity investments that recognized changes in fair value as a component of other comprehensive income. We adopted the standard on a modified retrospective basis with a cumulative-effect adjustment to the Consolidated Balance Sheet on January 1, 2018. The adoption of the ASU did not have a material effect on our results of operations, financial condition or cash flows.
ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. ASU 2016-15 is intended to reduce diversity in practice in how certain cash receipts and cash payments are presented and classified in the Consolidated Statement of Cash Flows by providing guidance on eight specific cash flow issues. We adopted the standard retrospectively on January 1, 2018. The adoption of the ASU did not have a material effect on our cash flows.
ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. ASU 2017-07 requires the service cost component of net benefit cost to be reported separately from the other components of net benefit cost in the income statement. The ASU also allows only the service cost component of net benefit cost to be eligible for capitalization. We adopted the standard retrospectively on January 1, 2018. Our reported 2017 operating earnings, when restated, will increase $59 due to the reclassification of the non-service cost components of net benefit cost, and our reported other income will decrease by the same amount, with no impact to net earnings. The area of the ASU related to capitalization did not have a material effect on our results of operations, financial condition or cash flows.
ASU 2016-02, Leases (Topic 842). ASU 2016-02 requires the recognition of lease rights and obligations as assets and liabilities on the balance sheet. Previously, lessees were not required to recognize on the balance sheet assets and liabilities arising from operating leases. The ASU also requires disclosure of key information about leasing arrangements. ASU 2016-02 is effective on January 1, 2019, using a modified retrospective method of adoption as of January 1, 2017. In January 2018, the FASB issued an exposure draft of the proposed ASU, Leases (Topic 842): Targeted Improvements. The proposed ASU provides an alternative transition method of adoption, permitting the recognition of a cumulative-effect adjustment to retained earnings on the date of adoption.
We intend to adopt the standard on the effective date, but have not yet selected a transition method. We are currently evaluating our population of leased assets in order to assess the impact of the ASU on our lease portfolio, and designing and implementing new processes and controls. Until this effort is completed, we cannot determine the effect of the ASU on our results of operations, financial condition or cash flows.
ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. ASU 2017-12 is intended to simplify hedge accounting by better aligning an entity’s financial reporting for hedging relationships with its risk management activities. The ASU also simplifies the application of the hedge accounting guidance. ASU 2017-12 is effective on January 1, 2019, with early adoption permitted. For cash flow hedges existing at the adoption date, the standard requires adoption on a modified retrospective basis with a cumulative-effect adjustment to the Consolidated Balance Sheet as of the beginning of the year of adoption. The amendments to presentation guidance and disclosure requirements are required to be adopted prospectively. We have not yet determined the effect of the ASU on our results of operations, financial condition or cash flows, nor have we selected a transition date.
Revenue Recognition
Each of these contract types presents advantages and disadvantages. Typically, we assume more risk with fixed-price contracts. However, these types of contracts offer additional profits when we complete the work for less than originally estimated. Cost-reimbursement contracts generally subject us to lower risk. Accordingly, the associated base fees are usually lower than fees earned on fixed-price contracts. Under time-and-materials contracts, our profit may vary if actual labor-hour rates vary significantly from the negotiated rates. Also, because these contracts can provide little or no fee for managing material costs, the content mix can impact profitability.
Contract Balances. The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets), and customer advances and deposits (contract liabilities) on the Consolidated Balance Sheet. In our defense groups, amounts are billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals (e.g., biweekly or monthly) or upon achievement of contractual milestones. Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. However, we sometimes receive advances or deposits from our customers, particularly on our international contracts, before revenue is recognized, resulting in contract liabilities. These assets and liabilities are reported on the Consolidated Balance Sheet on a contract-by-contract basis at the end of each reporting period. In our Aerospace group, we generally receive deposits from customers upon contract execution and upon achievement of contractual milestones. These deposits are liquidated when revenue is recognized.
The majority of our revenue is derived from long-term contracts and programs that can span several years. We account for revenue in accordance with ASC Topic 606.
Performance Obligations. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account in ASC Topic 606. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. The majority of our contracts have a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and is, therefore, not distinct. Some of our contracts have multiple performance obligations, most commonly due to the contract covering multiple phases of the product lifecycle (development, production, maintenance and support). For contracts with multiple performance obligations, we allocate the contract’s transaction price to each performance obligation using our best estimate of the standalone selling price of each distinct good or service in the contract. The primary method used to estimate standalone selling price is the expected cost plus a margin approach, under which we forecast our expected costs of satisfying a performance obligation and then add an appropriate margin for that distinct good or service.
Contract modifications are routine in the performance of our contracts. Contracts are often modified to account for changes in contract specifications or requirements. In most instances, contract modifications are for goods or services that are not distinct, and, therefore, are accounted for as part of the existing contract.
Our performance obligations are satisfied over time as work progresses or at a point in time. Revenue from products and services transferred to customers over time accounted for 71% of our revenue in 2017, 72% in 2016 and 68% in 2015. Substantially all of our revenue in the defense groups is recognized over time, because control is transferred continuously to our customers. Typically, revenue is recognized over time using costs incurred to date relative to total estimated costs at completion to measure progress toward satisfying our performance obligations. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. Contract costs include labor, material, overhead and, when appropriate, G&A expenses.
Revenue from goods and services transferred to customers at a point in time accounted for 29% of our revenue in 2017, 28% in 2016 and 32% in 2015. The majority of our revenue recognized at a point in time is for the manufacture of business-jet aircraft in our Aerospace group. Revenue on these contracts is recognized when the customer obtains control of the asset, which is generally upon delivery and acceptance by the customer of the fully outfitted aircraft.
On December 31, 2017, we had $63.2 billion of remaining performance obligations, which we also refer to as total backlog. We expect to recognize approximately 40% of our remaining performance obligations as revenue in 2018, an additional 40% by 2020 and the balance thereafter.
Contract Estimates. Accounting for long-term contracts and programs involves the use of various techniques to estimate total contract revenue and costs. For long-term contracts, we estimate the profit on a contract as the difference between the total estimated revenue and expected costs to complete a contract and recognize that profit over the life of the contract.
Contract estimates are based on various assumptions to project the outcome of future events that often span several years. These assumptions include labor productivity and availability; the complexity of the work to be performed; the cost and availability of materials; the performance of subcontractors; and the availability and timing of funding from the customer.
The nature of our contracts gives rise to several types of variable consideration, including claims and award and incentive fees. We include in our contract estimates additional revenue for submitted contract modifications or claims against the customer when we believe we have an enforceable right to the modification or claim, the amount can be estimated reliably and its realization is probable. In evaluating these criteria, we consider the contractual/legal basis for the claim, the cause of any additional costs incurred, the reasonableness of those costs and the objective evidence available to support the claim. We include award or incentive fees in the estimated transaction price when there is a basis to reasonably estimate the amount of the fee. These estimates are based on historical award experience, anticipated performance and our best judgment at the time. Because of our certainty in estimating these amounts, they are included in the transaction price of our contracts and the associated remaining performance obligations.
As a significant change in one or more of these estimates could affect the profitability of our contracts, we review and update our contract-related estimates regularly. We recognize adjustments in estimated profit on contracts under the cumulative catch-up method. Under this method, the impact of the adjustment on profit recorded to date on a contract is recognized in the period the adjustment is identified. Revenue and profit in future periods of contract performance are recognized using the adjusted estimate. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, we recognize the total loss in the period it is identified.
Earnings Per Share
We compute basic earnings per share (EPS) using net earnings for the period and the weighted average number of common shares outstanding during the period.
Fair Value of Financial Instruments
Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between marketplace participants. Various valuation approaches can be used to determine fair value, each requiring different valuation inputs. The following hierarchy classifies the inputs used to determine fair value into three levels:
Level 1 - quoted prices in active markets for identical assets or liabilities;
Level 2 - inputs, other than quoted prices, observable by a marketplace participant either directly or indirectly; and
Level 3 - unobservable inputs significant to the fair value measurement.
Tax Uncertainties
Tax Uncertainties. For all periods open to examination by tax authorities, we periodically assess our liabilities and contingencies based on the latest available information. Where we believe there is more than a 50% chance that our tax position will not be sustained, we record our best estimate of the resulting tax liability, including interest, in the Consolidated Financial Statements. We include any interest or penalties incurred in connection with income taxes as part of income tax expense. The total amount of these tax liabilities on December 31, 2017, was not material to our results of operations, financial condition or cash flows.
We participate in the IRS Compliance Assurance Process (CAP), a real-time audit of our consolidated federal corporate income tax return. The IRS has examined our consolidated federal income tax returns through 2016. We do not expect the resolution of tax matters for open years to have a material impact on our results of operations, financial condition, cash flows or effective tax rate.
Based on all known facts and circumstances and current tax law, we believe the total amount of any unrecognized tax benefits on December 31, 2017, was not material to our results of operations, financial condition or cash flows, and if recognized, would not have a material impact on our effective tax rate. In addition, there are no tax positions for which it is reasonably possible that the unrecognized tax benefits will vary significantly over the next 12 months, producing, individually or in the aggregate, a material effect on our results of operations, financial condition or cash flows.
Accounts and Unbilled Receivables
Accounts receivable represent amounts billed and currently due from customers. Payment is typically received from our customers either at periodic intervals (e.g., biweekly or monthly) or upon achievement of contractual milestones.
Unbilled receivables represent revenue recognized on long-term contracts (contract costs and estimated profits) less associated advances and progress billings. These amounts will be billed in accordance with the agreed-upon contractual terms or upon achievement of contractual milestones.
Inventories
The majority of our inventories are for business-jet aircraft. Our inventories are stated at the lower of cost or net realizable value. Work in process represents largely labor, material and overhead costs associated with aircraft in the manufacturing process and is based primarily on the estimated average unit cost in a production lot. Raw materials are valued primarily on the first-in, first-out method. We record pre-owned aircraft acquired in connection with the sale of new aircraft at the lower of the trade-in value or the estimated net realizable value.
Derivatives Instruments and Hedging Activities
Foreign Currency Risk and Hedging Activities. Our foreign currency exchange rate risk relates to receipts from customers, payments to suppliers and inter-company transactions denominated in foreign currencies. To the extent possible, we include terms in our contracts that are designed to protect us from this risk. Otherwise, we enter into derivative financial instruments, principally foreign currency forward purchase and sale contracts, designed to offset and minimize our risk. The dollar-weighted three-year average maturity of these instruments generally matches the duration of the activities that are at risk.
We record changes in the fair value of derivative financial instruments in operating costs and expenses in the Consolidated Statement of Earnings or in other comprehensive loss (OCL) within the Consolidated Statement of Comprehensive Income depending on whether the derivative is designated and qualifies for hedge accounting. Gains and losses related to derivative financial instruments that qualify as cash flow hedges are deferred in OCL until the underlying transaction is reflected in earnings. We adjust derivative financial instruments not designated as cash flow hedges to market value each period and record the gain or loss in the Consolidated Statement of Earnings. The gains and losses on these instruments generally offset losses and gains on the assets, liabilities and other transactions being hedged. Gains and losses resulting from hedge ineffectiveness are recognized in the Consolidated Statement of Earnings for all derivative financial instruments, regardless of designation.
Net gains and losses on derivative financial instruments recognized in earnings, including gains and losses related to hedge ineffectiveness, were not material to our results of operations in any of the past three years. Net gains and losses reclassified to earnings from OCL were not material to our results of operations in any of the past three years, and we do not expect the amount of these gains and losses that will be reclassified to earnings in 2018 to be material.
We are exposed to market risk, primarily from foreign currency exchange rates, interest rates, commodity prices and investments. We may use derivative financial instruments to hedge some of these risks as described below.
Interest Rate Risk. Our financial instruments subject to interest rate risk include fixed-rate long-term debt obligations and variable-rate commercial paper. However, the risk associated with these instruments is not material.
Commodity Price Risk. We are subject to rising labor and commodity price risk, primarily on long-term, fixed-price contracts. To the extent possible, we include terms in our contracts that are designed to protect us from these risks. Some of the protective terms included in our contracts are considered derivative financial instruments but are not accounted for separately, because they are clearly and closely related to the host contract. We have not entered into any material commodity hedging contracts but may do so as circumstances warrant. We do not believe that changes in labor or commodity prices will have a material impact on our results of operations or cash flows.
Investment Risk. Our investment policy allows for purchases of fixed-income securities with an investment-grade rating and a maximum maturity of up to five years.
Foreign Currency and Financial Statement Translation
Foreign Currency Financial Statement Translation. We translate foreign currency balance sheets from our international businesses’ functional currency (generally the respective local currency) to U.S. dollars at end-of-period exchange rates, and statements of earnings at average exchange rates for each period. The resulting foreign currency translation adjustments are a component of OCL.
We do not hedge the fluctuation in reported revenue and earnings resulting from the translation of these international operations’ results into U.S. dollars. The impact of translating our non-U.S. operations’ revenue into U.S. dollars was not material to our results of operations in any of the past three years. In addition, the effect of changes in foreign exchange rates on non-U.S. cash balances was not material in each of the past three years.
Commitments and Contingencies
Environmental
We are subject to and affected by a variety of federal, state, local and foreign environmental laws and regulations. We are directly or indirectly involved in environmental investigations or remediation at some of our current and former facilities and third-party sites that we do not own but where we have been designated a Potentially Responsible Party (PRP) by the U.S. Environmental Protection Agency or a state environmental agency. Based on historical experience, we expect that a significant percentage of the total remediation and compliance costs associated with these facilities will continue to be allowable contract costs and, therefore, recoverable under U.S. government contracts.
As required, we provide financial assurance for certain sites undergoing or subject to investigation or remediation. We accrue environmental costs when it is probable that a liability has been incurred and the amount can be reasonably estimated. Where applicable, we seek insurance recovery for costs related to environmental liabilities. We do not record insurance recoveries before collection is considered probable. Based on all known facts and analyses, we do not believe that our liability at any individual site, or in the aggregate, arising from such environmental conditions will be material to our results of operations, financial condition or cash flows. We also do not believe that the range of reasonably possible additional loss beyond what has been recorded would be material to our results of operations, financial condition or cash flows.
Other
Government Contracts. As a government contractor, we are subject to U.S. government audits and investigations relating to our operations, including claims for fines, penalties, and compensatory and treble damages. We believe the outcome of such ongoing government audits and investigations will not have a material impact on our results of operations, financial condition or cash flows.
In the performance of our contracts, we routinely request contract modifications that require additional funding from the customer. Most often, these requests are due to customer-directed changes in the scope of work. While we are entitled to recovery of these costs under our contracts, the administrative process with our customer may be protracted. Based on the circumstances, we periodically file requests for equitable adjustment (REAs) that are sometimes converted into claims. In some cases, these requests are disputed by our customer. We believe our outstanding modifications, REAs and other claims will be resolved without material impact to our results of operations, financial condition or cash flows.
Letters of Credit and Guarantees. In the ordinary course of business, we have entered into letters of credit, bank guarantees, surety bonds and other similar arrangements with financial institutions and insurance carriers
In addition, from time to time and in the ordinary course of business, we contractually guarantee the payment or performance of our subsidiaries arising under certain contracts.
Aircraft Trade-ins. In connection with orders for new aircraft in funded contract backlog, our Aerospace group has outstanding options with some customers to trade in aircraft as partial consideration in their new-aircraft transaction. These trade-in commitments are generally structured to establish the fair market value of the trade-in aircraft at a date generally 45 or fewer days preceding delivery of the new aircraft to the customer. At that time, the customer is required to either exercise the option or allow its expiration. Any excess of the pre-established trade-in price above the fair market value at the time the new aircraft is delivered is treated as a reduction of revenue in the new-aircraft sales transaction.
Product Warranties
Product Warranties. We provide warranties to our customers associated with certain product sales. We record estimated warranty costs in the period in which the related products are delivered. The warranty liability recorded at each balance sheet date is generally based on the number of months of warranty coverage remaining for the products delivered and the average historical monthly warranty payments. Warranty obligations incurred in connection with long-term production contracts are accounted for within the contract estimates at completion. Our other warranty obligations, primarily for business-jet aircraft, are included in other current and noncurrent liabilities on the Consolidated Balance Sheet.
Equity Compensation Plans
Stock Options. Stock options granted under our equity compensation plans are issued with an exercise price at the fair value of our common stock determined by the average of the high and low stock prices as listed on the New York Stock Exchange on the date of grant.
Restricted Stock/RSUs. The fair value of restricted stock and RSUs equals the average of the high and low market prices of our common stock as listed on the New York Stock Exchange on the date of grant. Grants of restricted stock are awards of shares of common stock. Participation units represent obligations that have a value derived from or related to the value of our common stock. These include stock appreciation rights, phantom stock units and RSUs, and are payable in cash or common stock.
Restricted stock and RSUs generally vest over a three-year restriction period after the grant date, during which recipients may not sell, transfer, pledge, assign or otherwise convey their restricted shares to another party. During this period, restricted stock recipients receive cash dividends on their restricted shares and are entitled to vote those shares, while RSU recipients receive dividend-equivalent units instead of cash dividends and are not entitled to vote their RSUs or dividend-equivalent units.
We grant RSUs with a performance measure derived from a non-GAAP-based management metric, return on invested capital (ROIC). Depending on the company’s performance with respect to this metric, the number of RSUs earned may be less than, equal to or greater than the original number of RSUs awarded subject to a payout range.
We generally recognize compensation expense related to restricted stock and RSUs on a straight-line basis over the vesting period
We recognize compensation expense related to stock options on a straight-line basis over the vesting period of the awards, net of estimated forfeitures. Estimated forfeitures are based on our historical forfeiture experience. We estimate the fair value of stock options on the date of grant using the Black-Scholes option pricing model
Equity-based Compensation Expense. Equity-based compensation expense is included in G&A expenses.
Equity Compensation Overview. We have equity compensation plans for employees, as well as for non-employee members of our board of directors. The equity compensation plans seek to provide an effective means of attracting and retaining directors, officers and key employees, and to provide them with incentives to enhance our growth and profitability. Under the equity compensation plans, awards may be granted to officers, employees or non-employee directors in common stock, options to purchase common stock, restricted shares of common stock, participation units or any combination of these.
Annually, we grant awards of stock options, restricted stock and RSUs to participants in our equity compensation plans in early March. Additionally, we may make limited ad hoc grants on a quarterly basis for new hires or promotions. We issue common stock under our equity compensation plans from treasury stock.
Retirement Plans
Plan Assets
A committee of our board of directors is responsible for the strategic oversight of our defined-benefit retirement plan assets held in trust. Management develops investment policies and provides oversight of a third-party investment manager who reports to the committee on a regular basis.  The outsourced third-party investment manager develops investment strategies and makes all day-to-day investment decisions related to defined-benefit retirement plan assets in accordance with our investment policy and target allocation percentages.
Our investment policy endeavors to strike the appropriate balance among capital preservation, asset growth and current income. The objective of our investment policy is to generate future returns consistent with our assumed long-term rate of return used to determine our benefit obligations and net annual benefit cost. Target allocation percentages vary over time depending on the perceived risk and return potential of various asset classes and market conditions.
Pension Benefits. We have seven noncontributory and five contributory trusteed, qualified defined-benefit pension plans covering eligible government business employees, and two noncontributory and four contributory plans covering eligible commercial business employees, including some employees of our international operations. The primary factors affecting the benefits earned by participants in our pension plans are employees’ years of service and compensation levels. Our primary government pension plans, which comprise the majority of our unfunded obligation, were closed to new salaried participants on January 1, 2007. Additionally, we made changes to these plans for certain participants effective in 2014 that limit or cease the benefits that accrue for future service. We made similar changes to our primary commercial pension plan in 2015.
We also sponsor one funded and several unfunded non-qualified supplemental executive retirement plans, which provide participants with additional benefits, including excess benefits over limits imposed on qualified plans by federal tax law.
Other Post-retirement Benefits. We maintain plans that provide post-retirement healthcare and life insurance coverage for certain employees and retirees. These benefits vary by employment status, age, service and salary level at retirement. The coverage provided and the extent to which the retirees share in the cost of the program vary throughout the company. The plans provide health and life insurance benefits only to those employees who retire directly from our service and not to those who terminate service prior to eligibility for retirement.
Contributions and Benefit Payments
It is our policy to fund our defined-benefit retirement plans in a manner that optimizes the tax deductibility and contract recovery of contributions considered within our capital deployment framework. Therefore, we may make discretionary contributions in addition to the required contributions determined in accordance with IRS regulations.
We provide defined-contribution benefits to eligible employees, as well as some remaining defined-benefit pension and other post-retirement benefits. Substantially all of our plans use a December 31 measurement date consistent with our fiscal year.
Retirement Plan Summary Information
Defined-contribution Benefits. We provide eligible employees the opportunity to participate in defined-contribution savings plans (commonly known as 401(k) plans), which permit contributions on a before-tax and after-tax basis. Employees may contribute to various investment alternatives. In most of these plans, we match a portion of the employees’ contributions.
More than 90% of our pension plan assets are held in a single trust for our primary U.S. government and commercial pension plans. On December 31, 2017, the trust was invested largely in publicly traded equities, fixed-income securities and commingled funds comprised of equity securities. The trust also invests in other asset classes consistent with our investment policy. Our investments in equity assets include U.S. and international securities and equity funds. Our investments in fixed-income assets include U.S. Treasury and U.S. agency securities, corporate bonds, mortgage-backed securities and other asset-backed securities. Our investment policy allows the use of derivative instruments when appropriate to reduce anticipated asset volatility, to gain exposure to an asset class or to adjust the duration of fixed-income assets.
Assets for our non-U.S. pension plans are held in trusts in the countries in which the related operations reside. Our non-U.S. operations maintain investment policies for their individual plans based on country-specific regulations. The non-U.S. plan assets are invested primarily in commingled funds comprised of equity and fixed-income securities.
We hold assets in VEBA trusts for some of our other post-retirement benefit plans. These assets are managed by a third-party investment manager with oversight by management and are generally invested in equities, fixed-income securities and commingled funds comprised of equity and fixed-income securities. Our asset allocation strategy for the VEBA trusts considers potential fluctuations in our other post-retirement benefit obligation, the taxable nature of certain VEBA trusts, tax deduction limits on contributions and the regulatory environment.
Our retirement plan assets are reported at fair value. See Note E for a discussion of the hierarchy for determining fair value. Our Level 1 assets include investments in publicly traded equity securities. These securities are actively traded and valued using quoted prices for identical securities from the market exchanges. Our Level 2 assets consist of fixed-income securities and commingled funds whose underlying investments are valued using observable marketplace inputs. The fair value of plan assets invested in fixed-income securities is generally determined using valuation models that use observable inputs such as interest rates, bond yields, low-volume market quotes and quoted prices for similar assets. Our plan assets that are invested in commingled funds are valued using a unit price or net asset value (NAV) that is based on the underlying investments of the fund. Our Level 3 assets include real estate funds, insurance deposit contracts and direct private equity investments.
Certain investments valued using NAV as a practical expedient are excluded from the fair value hierarchy. These investments are redeemable at NAV on a monthly or quarterly basis and have redemption notice periods of up to 90 days.
Government Contract Considerations
Our contractual arrangements with the U.S. government provide for the recovery of contributions to our pension and other post-retirement benefit plans covering employees working in our defense business groups. For non-funded plans, our government contracts allow us to recover claims paid. Following payment, these recoverable amounts are allocated to contracts and billed to the customer in accordance with the Cost Accounting Standards (CAS) and specific contractual terms. For some of these plans, the cumulative pension and other post-retirement benefit cost exceeds the amount currently allocable to contracts. To the extent recovery of the cost is considered probable based on our backlog and probable follow-on contracts, we defer the excess in other contract costs in other current assets on the Consolidated Balance Sheet until the cost is allocable to contracts. See Note A for a discussion of our other contract costs. For other plans, the amount allocated to contracts and included in revenue has exceeded the plans’ cumulative benefit cost. We have deferred recognition of these excess earnings on the Consolidated Balance Sheet.
Defined-benefit Retirement Plan Summary Financial Information
Estimating retirement plan assets, liabilities and costs requires the extensive use of actuarial assumptions. These include the long-term rate of return on plan assets, the interest rates used to discount projected benefit payments, healthcare cost trend rates and future salary increases. Given the long-term nature of the assumptions being made, actual outcomes can and often do differ from these estimates.
Our annual benefit cost consists of three primary elements: the cost of benefits earned by employees for services rendered during the year, an interest charge on our plan liabilities and an assumed return on our plan assets for the year. The annual cost also includes gains and losses resulting from changes in actuarial assumptions, differences between the actual and assumed long-term rate of return on assets, and gains and losses resulting from changes we make to plan benefit terms.
We recognize an asset or liability on the Consolidated Balance Sheet equal to the funded status of each of our defined-benefit retirement plans. The funded status is the difference between the fair value of the plan’s assets and its benefit obligation. Changes in plan assets and liabilities due to differences between actuarial assumptions and the actual results of the plan are deferred in OCL rather than charged to earnings. These differences are then amortized over future years as a component of our annual benefit cost. We amortize actuarial differences under qualified plans on a straight-line basis over the average remaining service period of eligible employees. If all of a plan’s participants are inactive, we amortize these differences over the average remaining life expectancy of the plan participants. We recognize the difference between the actual and expected return on plan assets for qualified plans over five years. The deferral of these differences reduces the volatility of our annual benefit cost that can result either from year-to-year changes in the assumptions or from actual results that are not necessarily representative of the long-term financial position of these plans. We recognize differences under nonqualified plans immediately.
We base the discount rates on a current yield curve developed from a portfolio of high-quality, fixed-income investments with maturities consistent with the projected benefit payout period. Beginning in 2016, we refined the method used to determine the service and interest cost components of our net annual benefit cost. Previously, the cost was determined using a single weighted-average discount rate derived from the yield curve described above. Under the refined method, known as the spot rate approach, we use individual spot rates along the yield curve that correspond with the timing of each service cost and discounted benefit obligation payment. We believe this change provides a more precise measurement of service and interest costs by improving the correlation between projected service cost and discounted benefit obligation cash outflows and corresponding spot rates on the yield curve. We accounted for this change prospectively as a change in accounting estimate.
We determine the long-term rate of return on assets based on consideration of historical and forward-looking returns and the current and expected asset allocation strategy. In 2017, we decreased the expected long-term rate of return on assets in our primary U.S. government and commercial pension plans by 75 basis points following an assessment of the historical and expected long-term returns of our various asset classes.
Retirement plan assumptions are based on our best judgment, including consideration of current and future market conditions. Changes in these estimates impact future pension and other post-retirement benefit cost. As discussed above, we defer recognition of the cumulative benefit cost for our government plans in excess of costs allocated to contracts and included in revenue. Therefore, the impact of annual changes in financial reporting assumptions on the cost for these plans does not immediately affect our operating results.
Retirement Plan Assumptions
We calculate the plan assets and liabilities for a given year and the net annual benefit cost for the subsequent year using assumptions determined as of December 31 of the year in question.
Business Group Information
We operate in four business groups: Aerospace, Combat Systems, Information Systems and Technology, and Marine Systems. We organize our business groups in accordance with the nature of products and services offered. We measure each group’s profitability based on operating earnings. As a result, we do not allocate net interest, other income and expense items, and income taxes to our business groups.