Basis of Presentation	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	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"). As used in the Notes to the Condensed Consolidated Financial Statements (Unaudited), the terms "HII" and "the Company" refer to HII and its subsidiaries. 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. 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, 2024 (the "2024 Annual Report on Form 10-K"). 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. This practice only exists 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. Fair Value of Financial Instruments - Except for the Company's long-term debt, the carrying amounts of the Company's financial instruments that are 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 to fund certain non-qualified pension plans. These trusts were valued at $237 million and $233 million as of June 30, 2025, and December 31, 2024, respectively, and are presented within miscellaneous other assets on the unaudited condensed consolidated statements of financial position. These trusts consist primarily of investments in marketable securities, which are held at fair value within Level 1 of the fair value hierarchy. The estimated fair values of the Company's total long-term debt, including the current portion of long-term debt and excluding finance lease liabilities, as of June 30, 2025, and December 31, 2024, were $2,690 million and $3,110 million, respectively. There was no current portion of long-term debt, excluding finance lease liabilities, as of June 30, 2025. The estimated fair value of the current portion of the Company's long-term debt, excluding finance lease liabilities, was $497 million as of December 31, 2024. The fair values of the Company's long-term debt were calculated based on recent trades of the Company's debt instruments in inactive markets, which fall within Level 2 of the fair value hierarchy. Debt - On May 1, 2025, the Company repaid $500 million aggregate principal amount of its 3.844% senior notes upon their maturity. The repayment was funded using a combination of cash on hand and proceeds from the Company’s commercial paper program.

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"). As used in the Notes to the Condensed Consolidated Financial Statements (Unaudited), the terms "HII" and "the Company" refer to HII and its subsidiaries. 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.

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, 2024 (the "2024 Annual Report on Form 10-K").

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. This practice only exists 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.

Fair Value of Financial Instruments - Except for the Company's long-term debt, the carrying amounts of the Company's financial instruments that are 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 to fund certain non-qualified pension plans. These trusts were valued at $237 million and $233 million as of June 30, 2025, and December 31, 2024, respectively, and are presented within miscellaneous other assets on the unaudited condensed consolidated statements of financial position. These trusts consist primarily of investments in marketable securities, which are held at fair value within Level 1 of the fair value hierarchy.

The estimated fair values of the Company's total long-term debt, including the current portion of long-term debt and excluding finance lease liabilities, as of June 30, 2025, and December 31, 2024, were $2,690 million and $3,110 million, respectively. There was no current portion of long-term debt, excluding finance lease liabilities, as of June 30, 2025. The estimated fair value of the current portion of the Company's long-term debt, excluding finance lease liabilities, was $497 million as of December 31, 2024. The fair values of the Company's long-term debt were calculated based on recent trades of the Company's debt instruments in inactive markets, which fall within Level 2 of the fair value hierarchy.

Debt - On May 1, 2025, the Company repaid $500 million aggregate principal amount of its 3.844% senior notes upon their maturity. The repayment was funded using a combination of cash on hand and proceeds from the Company’s commercial paper program.