Basis of Presentation	6 Months Ended
Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	BASIS OF PRESENTATION Principles of Consolidation - The unaudited condensed consolidated financial statements of HII and its subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP") and the instructions to Form 10-Q promulgated by the Securities and Exchange Commission ("SEC"). All intercompany transactions and balances are eliminated in consolidation. For classification of current assets and liabilities related to its long-term production contracts, the Company uses the duration of these contracts as its operating cycle, which is generally longer than one year. Additionally, certain prior year amounts have been reclassified to conform to the current year presentation. See Note 3: Accounting Standards Updates. These unaudited condensed consolidated financial statements include all adjustments of a normal recurring nature considered necessary by management for a fair presentation of the unaudited condensed consolidated financial position, results of operations, and cash flows and should be read in conjunction with the Company's audited consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017. The quarterly information is labeled using a calendar convention; that is, first quarter is consistently labeled as ending on March 31, second quarter as ending on June 30, and third quarter as ending on September 30. It is management's long-standing practice to establish interim closing dates using a "fiscal" calendar, which requires the businesses to close their books on a Friday near these quarter-end dates in order to normalize the potentially disruptive effects of quarterly closings on business processes. The effects of this practice only exist for interim periods within a reporting year. Accounting Estimates - The preparation of the Company's unaudited condensed consolidated financial statements requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingencies at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Estimates have been prepared on the basis of the most current and best available information, and actual results could differ materially from those estimates. In August 2011, the Budget Control Act established limits on U.S. Government discretionary spending and provided for potential sequestration cuts to defense spending and non-defense discretionary spending. The Bipartisan Budget Act of 2018 (the "BBA 2018") provided sequestration relief for fiscal years 2018 and 2019. Sequestration remains in effect for fiscal years 2020 and 2021 and could result in significant decreases in DoD spending that could negatively impact the Company's consolidated financial position, results of operations, or cash flows, as well as its estimated recovery of goodwill and other long-lived assets. Revenue Recognition - Effective January 1, 2018, the Company adopted the requirements of Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606) and related amendments. Prior to January 1, 2018, the Company recognized revenue in accordance with Accounting Standards Codification Topic 605-35 Construction-Type and Production-Type Contracts utilizing the cost-to-cost measure of the percentage-of-completion method of accounting, primarily based upon total costs incurred, with incentive fees included in sales when the amounts could be reasonably determined and estimated. Amounts representing change orders, claims, requests for equitable adjustment, or limitations of funding were included in sales only when they could be reliably estimated and realization was probable. For additional information on the new standard and the impact to the Company's results of operations, refer to Note 3: Accounting Standards Updates. Most of the Company's revenues are derived from long-term contracts for the production of goods and services provided to its U.S. Government customers. The Company generally recognizes revenues on contracts with U.S. Government customers over time using a cost-to-cost measure of progress. The use of the cost-to-cost method to measure performance progress over time is supported by clauses in the related contracts that allow the customer to unilaterally terminate the contract for convenience, pay the Company for costs incurred plus a reasonable profit, and take control of any work in process. The Company utilizes the cost-to-cost method to measure performance progress, because it best reflects the continuous transfer of control over the related goods and services to the customer as the Company satisfies its performance obligations. Where the customer is not a U.S. Government entity, the Company may recognize revenue over time or at a point in time when control transfers upon delivery, depending upon the facts and circumstances of the related arrangement. Where the Company determines that revenue should be recognized over time, the Company utilizes a measure of progress that best depicts the transfer of control of the relevant goods and services to the customer. Generally, the terms and conditions of the contracts result in a transfer of control over the related goods and services as the Company satisfies its performance obligations. Accordingly, the Company recognizes revenue over time using the cost-to-cost method to measure performance progress. The Company may, however, utilize a measure of progress other than cost-to-cost, such as a labor-based measure of progress, or recognize revenue at the point in time at which control is transferred to the customer if the terms and conditions of the arrangement require such accounting. When using the cost-to-cost method to measure performance progress, certain contracts may include costs that are not representative of performance progress, such as large upfront purchases of uninstalled materials, unexpected waste, or inefficiencies. In these cases, the Company adjusts its measure of progress to exclude such costs, with the goal of better reflecting the transfer of control over the related goods or services to the customer and recognizing revenue only to the extent of the costs incurred that reflect the Company's performance under the contract. A performance obligation is a promise to transfer a distinct good or service to the customer and is the unit of account for which revenue is recognized. To determine the proper revenue recognition method, consideration is given to whether two or more contracts should be combined and accounted for as one contract and whether a single contract consists of more than one performance obligation. For contracts with multiple performance obligations, the contract transaction price is allocated to each performance obligation using an estimate of the standalone selling price based upon expected cost plus a margin at contract inception, which is generally the price disclosed in the contract. Contracts are often modified to account for changes in contract specifications and requirements. In the majority of circumstances, modifications do not result in additional performance obligations that are distinct from the existing performance obligations in the contract and the effects of the modifications are recognized as an adjustment to revenue on a cumulative catch-up basis. Alternatively, in instances where the performance obligations in the modifications are deemed distinct, contract modifications are accounted for prospectively. The amount of revenue recognized as the Company satisfies performance obligations associated with contracts with customers is based upon the determination of transaction price. Transaction price reflects the amount of consideration to which the Company expects to be entitled for performance under the terms and conditions of the relevant contract and may reflect fixed and variable components, including shareline incentive fees whereby the value of the contract is variable based upon the amount of costs incurred, as well as other incentive fees based upon achievement of contractual schedule commitments or other specified criteria in the contract. Shareline incentive fees are determined based upon the formula under the relevant contract using the Company’s estimated cost to complete each period. The Company generally utilizes a most likely amount approach to estimate variable consideration. In all such instances, the estimated revenues represent those amounts for which the Company believes a significant reversal of revenue is not probable. Contract Estimates - In estimating contract costs, the Company utilizes a profit-booking rate based upon performance expectations that takes into consideration a number of assumptions and estimates regarding risks related to technical requirements, feasibility, schedule, and contract costs. Management performs periodic reviews of the contracts to evaluate the underlying risks, which may increase the profit-booking rate as the Company is able to mitigate and retire such risks. Conversely, if the Company is not able to retire these risks, cost estimates may increase, resulting in a lower profit-booking rate. The cost estimation process requires significant judgment and is based upon the professional knowledge and experience of the Company’s engineers, program managers, and financial professionals. Factors considered in estimating the work to be completed and ultimate contract recovery include the availability, productivity, and cost of labor, the nature and complexity of the work to be performed, the effect of change orders, the availability of materials, the effect of any performance delays, the availability and timing of funding from the customer, and the recoverability of any claims included in the estimates to complete. Changes in estimates of sales, costs, and profits on a performance obligation are recognized using the cumulative catch-up method of accounting, which recognizes in the current period the cumulative effect of the changes in current and prior periods. A significant change in an estimate on one or more contracts in a period could have a material effect on the Company's unaudited condensed consolidated financial position or results of operations for that period. When estimates of total costs to be incurred exceed estimates of total revenue to be earned on a performance obligation related to a complex, construction-type contract, a provision for the entire loss on the performance obligation is recognized in the period the loss is determined. Accounts Receivable - Accounts receivable include amounts related to any unconditional Company right to receive consideration and are presented as receivables in the unaudited condensed consolidated statement of financial position, separate from other contract balances. Accounts receivable are comprised of amounts billed and currently due from customers. The Company reports accounts receivable net of an allowance for doubtful accounts. Because the Company's accounts receivable are primarily with the U.S. Government or with companies acting as a contractor to the U.S. Government, the Company does not have material exposure to accounts receivable credit risk. Contract Assets - Contract assets primarily relate to the Company’s rights to consideration for work completed but not billed as of the reporting date when the right to payment is not just subject to the passage of time, including retention amounts. Contract assets are classified as current assets and, in accordance with industry practice, include amounts that may be billed and collected beyond one year due to the long term nature of many of the Company's contracts. Contract assets are transferred to accounts receivable when the right to consideration becomes unconditional. Contract Liabilities - Contract liabilities are comprised of advance payments, billings in excess of revenues, and deferred revenue amounts. Such advances are generally not considered a significant financing component, because they are utilized to pay for contract costs within a one year period. Contract liability amounts are recognized as revenue once the requisite performance progress has occurred. Inventoried Costs - Inventoried costs primarily relate to company owned raw materials, which are stated at the lower of cost or net realizable value, generally using the average cost method, and costs capitalized pursuant to applicable provisions of the Federal Acquisition Regulation ("FAR") and Cost Accounting Standards ("CAS"). Under the Company's U.S. Government contracts, the customer asserts title to, or a security interest in, inventories related to such contracts as a result of contract advances, performance-based payments, and progress payments. In accordance with industry practice, inventoried costs are classified as current assets and include amounts related to contracts having production cycles longer than one year. Warranty Costs - Certain of the Company’s contracts contain assurance-type warranty provisions, which generally promise that the service or vessel will comply with agreed upon specifications. In such instances, the Company accrues the estimated loss by a charge to income in the relevant period. In limited circumstances,the Company's complex construction type contracts may provide the customer with an option to purchase a warranty or provide an extended assurance service coupled with the primary assurance warranty. In such cases, the Company accounts for the warranty as a separate performance obligation to the extent it is material within the context of the contract. Warranty liabilities are reported within other current liabilities and are not material. Government Grants - The Company recognizes incentive grants, inclusive of transfers of depreciable assets, from federal, state, and local governments at fair value upon compliance with the conditions of their receipt and reasonable assurance that the grants will be received or the depreciable assets will be transferred. Grants in recognition of specific expenses are recognized in the same period as an offset to those related expenses. Grants related to depreciable assets are recognized over the periods and in the proportions in which depreciation expense on those assets is recognized. For the six months ended June 30, 2018, the Company recognized cash grant benefits of approximately $19 million in other long-term liabilities in the unaudited condensed consolidated statements of financial position. For the six months ended June 30, 2017, the Company recognized no grant benefits. Fair Value of Financial Instruments - Except for the Company's long-term debt, the carrying amounts of the Company's financial instruments recorded at historical cost approximate fair value due to the short-term nature of the instruments and low credit risk associated with the respective counterparties. The Company maintains multiple grantor trusts established to fund certain non-qualified pension plans. These trusts were valued at $104 million and $94 million as of June 30, 2018, and December 31, 2017, respectively, and are presented within miscellaneous other assets within the unaudited condensed consolidated statements of financial position. These trusts consist primarily of available-for-sale investments in marketable securities, which are held at fair value within Level 1 of the fair value hierarchy. Related Party Transactions - On March 29, 2011, HII entered into a Separation and Distribution Agreement (the "Separation Agreement") with its former parent company, Northrop Grumman Corporation ("Northrop Grumman"), and Northrop Grumman's subsidiaries (Northrop Grumman Shipbuilding, Inc. and Northrop Grumman Systems Corporation), pursuant to which HII was legally and structurally separated from Northrop Grumman. As of December 31, 2017, the Company was due $8 million from Northrop Grumman under spin-off related agreements. For the six months ended June 30, 2018, the Company received $8 million from Northrup Grumman under spin-off related agreements. As of each of June 30, 2018, and December 31, 2017, the Company had $84 million outstanding under Industrial Revenue Bonds issued by the Mississippi Business Finance Corporation. Prior to the spin-off, repayment of principal and interest was guaranteed by Northrop Grumman Systems Corporation. The guaranty remains in effect, and the Company has agreed to indemnify Northrop Grumman Systems Corporation for any losses related to the guaranty.

BASIS OF PRESENTATION

Principles of Consolidation - The unaudited condensed consolidated financial statements of HII and its subsidiaries have been prepared in conformity with accounting principles generally accepted in the United States of America ("GAAP") and the instructions to Form 10-Q promulgated by the Securities and Exchange Commission ("SEC"). All intercompany transactions and balances are eliminated in consolidation. For classification of current assets and liabilities related to its long-term production contracts, the Company uses the duration of these contracts as its operating cycle, which is generally longer than one year. Additionally, certain prior year amounts have been reclassified to conform to the current year presentation. See Note 3: Accounting Standards Updates.

These unaudited condensed consolidated financial statements include all adjustments of a normal recurring nature considered necessary by management for a fair presentation of the unaudited condensed consolidated financial position, results of operations, and cash flows and should be read in conjunction with the Company's audited consolidated financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017.

The quarterly information is labeled using a calendar convention; that is, first quarter is consistently labeled as ending on March 31, second quarter as ending on June 30, and third quarter as ending on September 30. It is management's long-standing practice to establish interim closing dates using a "fiscal" calendar, which requires the businesses to close their books on a Friday near these quarter-end dates in order to normalize the potentially disruptive effects of quarterly closings on business processes. The effects of this practice only exist for interim periods within a reporting year.

Accounting Estimates - The preparation of the Company's unaudited condensed consolidated financial statements requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingencies at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Estimates have been prepared on the basis of the most current and best available information, and actual results could differ materially from those estimates.

In August 2011, the Budget Control Act established limits on U.S. Government discretionary spending and provided for potential sequestration cuts to defense spending and non-defense discretionary spending. The Bipartisan Budget Act of 2018 (the "BBA 2018") provided sequestration relief for fiscal years 2018 and 2019. Sequestration remains in effect for fiscal years 2020 and 2021 and could result in significant decreases in DoD spending that could negatively impact the Company's consolidated financial position, results of operations, or cash flows, as well as its estimated recovery of goodwill and other long-lived assets.

Revenue Recognition - Effective January 1, 2018, the Company adopted the requirements of Accounting Standards Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606) and related amendments. Prior to January 1, 2018, the Company recognized revenue in accordance with Accounting Standards Codification Topic 605-35 Construction-Type and Production-Type Contracts utilizing the cost-to-cost measure of the percentage-of-completion method of accounting, primarily based upon total costs incurred, with incentive fees included in sales when the amounts could be reasonably determined and estimated. Amounts representing change orders, claims, requests for equitable adjustment, or limitations of funding were included in sales only when they could be reliably estimated and realization was probable. For additional information on the new standard and the impact to the Company's results of operations, refer to Note 3: Accounting Standards Updates.

Most of the Company's revenues are derived from long-term contracts for the production of goods and services provided to its U.S. Government customers. The Company generally recognizes revenues on contracts with U.S. Government customers over time using a cost-to-cost measure of progress. The use of the cost-to-cost method to measure performance progress over time is supported by clauses in the related contracts that allow the customer to unilaterally terminate the contract for convenience, pay the Company for costs incurred plus a reasonable profit, and take control of any work in process. The Company utilizes the cost-to-cost method to measure performance progress, because it best reflects the continuous transfer of control over the related goods and services to the customer as the Company satisfies its performance obligations.

Where the customer is not a U.S. Government entity, the Company may recognize revenue over time or at a point in time when control transfers upon delivery, depending upon the facts and circumstances of the related arrangement. Where the Company determines that revenue should be recognized over time, the Company utilizes a measure of progress that best depicts the transfer of control of the relevant goods and services to the customer. Generally, the terms and conditions of the contracts result in a transfer of control over the related goods and services as the Company satisfies its performance obligations. Accordingly, the Company recognizes revenue over time using the cost-to-cost method to measure performance progress. The Company may, however, utilize a measure of progress other than cost-to-cost, such as a labor-based measure of progress, or recognize revenue at the point in time at which control is transferred to the customer if the terms and conditions of the arrangement require such accounting.

When using the cost-to-cost method to measure performance progress, certain contracts may include costs that are not representative of performance progress, such as large upfront purchases of uninstalled materials, unexpected waste, or inefficiencies. In these cases, the Company adjusts its measure of progress to exclude such costs, with the goal of better reflecting the transfer of control over the related goods or services to the customer and recognizing revenue only to the extent of the costs incurred that reflect the Company's performance under the contract.

A performance obligation is a promise to transfer a distinct good or service to the customer and is the unit of account for which revenue is recognized. To determine the proper revenue recognition method, consideration is given to whether two or more contracts should be combined and accounted for as one contract and whether a single contract consists of more than one performance obligation. For contracts with multiple performance obligations, the contract transaction price is allocated to each performance obligation using an estimate of the standalone selling price based upon expected cost plus a margin at contract inception, which is generally the price disclosed in the contract. Contracts are often modified to account for changes in contract specifications and requirements. In the majority of circumstances, modifications do not result in additional performance obligations that are distinct from the existing performance obligations in the contract and the effects of the modifications are recognized as an adjustment to revenue on a cumulative catch-up basis. Alternatively, in instances where the performance obligations in the modifications are deemed distinct, contract modifications are accounted for prospectively.

The amount of revenue recognized as the Company satisfies performance obligations associated with contracts with customers is based upon the determination of transaction price. Transaction price reflects the amount of consideration to which the Company expects to be entitled for performance under the terms and conditions of the relevant contract and may reflect fixed and variable components, including shareline incentive fees whereby the value of the contract is variable based upon the amount of costs incurred, as well as other incentive fees based upon achievement of contractual schedule commitments or other specified criteria in the contract. Shareline incentive fees are determined based upon the formula under the relevant contract using the Company’s estimated cost to complete each period. The Company generally utilizes a most likely amount approach to estimate variable consideration. In all such instances, the estimated revenues represent those amounts for which the Company believes a significant reversal of revenue is not probable.

Contract Estimates - In estimating contract costs, the Company utilizes a profit-booking rate based upon performance expectations that takes into consideration a number of assumptions and estimates regarding risks related to technical requirements, feasibility, schedule, and contract costs. Management performs periodic reviews of the contracts to evaluate the underlying risks, which may increase the profit-booking rate as the Company is able to mitigate and retire such risks. Conversely, if the Company is not able to retire these risks, cost estimates may increase, resulting in a lower profit-booking rate.

The cost estimation process requires significant judgment and is based upon the professional knowledge and experience of the Company’s engineers, program managers, and financial professionals. Factors considered in estimating the work to be completed and ultimate contract recovery include the availability, productivity, and cost of labor, the nature and complexity of the work to be performed, the effect of change orders, the availability of materials, the effect of any performance delays, the availability and timing of funding from the customer, and the recoverability of any claims included in the estimates to complete.

Changes in estimates of sales, costs, and profits on a performance obligation are recognized using the cumulative catch-up method of accounting, which recognizes in the current period the cumulative effect of the changes in current and prior periods. A significant change in an estimate on one or more contracts in a period could have a material effect on the Company's unaudited condensed consolidated financial position or results of operations for that period.

When estimates of total costs to be incurred exceed estimates of total revenue to be earned on a performance obligation related to a complex, construction-type contract, a provision for the entire loss on the performance obligation is recognized in the period the loss is determined.

Accounts Receivable - Accounts receivable include amounts related to any unconditional Company right to receive consideration and are presented as receivables in the unaudited condensed consolidated statement of financial position, separate from other contract balances. Accounts receivable are comprised of amounts billed and currently due from customers. The Company reports accounts receivable net of an allowance for doubtful accounts. Because the Company's accounts receivable are primarily with the U.S. Government or with companies acting as a contractor to the U.S. Government, the Company does not have material exposure to accounts receivable credit risk.

Contract Assets - Contract assets primarily relate to the Company’s rights to consideration for work completed but not billed as of the reporting date when the right to payment is not just subject to the passage of time, including retention amounts. Contract assets are classified as current assets and, in accordance with industry practice, include amounts that may be billed and collected beyond one year due to the long term nature of many of the Company's contracts. Contract assets are transferred to accounts receivable when the right to consideration becomes unconditional.

Contract Liabilities - Contract liabilities are comprised of advance payments, billings in excess of revenues, and deferred revenue amounts. Such advances are generally not considered a significant financing component, because they are utilized to pay for contract costs within a one year period. Contract liability amounts are recognized as revenue once the requisite performance progress has occurred.

Inventoried Costs - Inventoried costs primarily relate to company owned raw materials, which are stated at the lower of cost or net realizable value, generally using the average cost method, and costs capitalized pursuant to applicable provisions of the Federal Acquisition Regulation ("FAR") and Cost Accounting Standards ("CAS"). Under the Company's U.S. Government contracts, the customer asserts title to, or a security interest in, inventories related to such contracts as a result of contract advances, performance-based payments, and progress payments. In accordance with industry practice, inventoried costs are classified as current assets and include amounts related to contracts having production cycles longer than one year.

Warranty Costs - Certain of the Company’s contracts contain assurance-type warranty provisions, which generally promise that the service or vessel will comply with agreed upon specifications. In such instances, the Company accrues the estimated loss by a charge to income in the relevant period. In limited circumstances,the Company's complex construction type contracts may provide the customer with an option to purchase a warranty or provide an extended assurance service coupled with the primary assurance warranty. In such cases, the Company accounts for the warranty as a separate performance obligation to the extent it is material within the context of the contract. Warranty liabilities are reported within other current liabilities and are not material.

Government Grants - The Company recognizes incentive grants, inclusive of transfers of depreciable assets, from federal, state, and local governments at fair value upon compliance with the conditions of their receipt and reasonable assurance that the grants will be received or the depreciable assets will be transferred. Grants in recognition of specific expenses are recognized in the same period as an offset to those related expenses. Grants related to depreciable assets are recognized over the periods and in the proportions in which depreciation expense on those assets is recognized.

For the six months ended June 30, 2018, the Company recognized cash grant benefits of approximately $19 million in other long-term liabilities in the unaudited condensed consolidated statements of financial position. For the six months ended June 30, 2017, the Company recognized no grant benefits.

Fair Value of Financial Instruments - Except for the Company's long-term debt, the carrying amounts of the Company's financial instruments recorded at historical cost approximate fair value due to the short-term nature of the instruments and low credit risk associated with the respective counterparties.

The Company maintains multiple grantor trusts established to fund certain non-qualified pension plans. These trusts were valued at $104 million and $94 million as of June 30, 2018, and December 31, 2017, respectively, and are presented within miscellaneous other assets within the unaudited condensed consolidated statements of financial position. These trusts consist primarily of available-for-sale investments in marketable securities, which are held at fair value within Level 1 of the fair value hierarchy.

Related Party Transactions - On March 29, 2011, HII entered into a Separation and Distribution Agreement (the "Separation Agreement") with its former parent company, Northrop Grumman Corporation ("Northrop Grumman"), and Northrop Grumman's subsidiaries (Northrop Grumman Shipbuilding, Inc. and Northrop Grumman Systems Corporation), pursuant to which HII was legally and structurally separated from Northrop Grumman. As of December 31, 2017, the Company was due $8 million from Northrop Grumman under spin-off related agreements. For the six months ended June 30, 2018, the Company received $8 million from Northrup Grumman under spin-off related agreements. As of each of June 30, 2018, and December 31, 2017, the Company had $84 million outstanding under Industrial Revenue Bonds issued by the Mississippi Business Finance Corporation. Prior to the spin-off, repayment of principal and interest was guaranteed by Northrop Grumman Systems Corporation. The guaranty remains in effect, and the Company has agreed to indemnify Northrop Grumman Systems Corporation for any losses related to the guaranty.