v3.26.1
FAIR VALUE MEASUREMENTS (Details) - EBP 310 - USD ($)
Dec. 31, 2025
Dec. 31, 2024
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust $ 488,511,000 $ 442,383,000
Total Other Plan Investments 793,000 664,000
Short-term investment funds    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 793,000 664,000
Level 1    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 0 0
Level 1 | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 0 0
Level 2    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 0 0
Level 2 | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 0 0
Level 3    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 0 0
Level 3 | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 0 0
NAV    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 793,000 664,000
NAV | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total Other Plan Investments 793,000 664,000
Master Trust Balances    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 6,568,083,000 5,644,890,000
Master Trust Balances | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 21,639,000 21,658,000
Master Trust Balances | HII common stock    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 274,356,000 181,010,000
Master Trust Balances | Collective trust funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 5,820,851,000 5,040,576,000
Master Trust Balances | Schwab Personal Choice Retirement Account    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 451,237,000 401,646,000
Master Trust Balances | Level 1    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 722,565,000 580,065,000
Master Trust Balances | Level 1 | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 1 | HII common stock    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 274,356,000 181,010,000
Master Trust Balances | Level 1 | Collective trust funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 1 | Schwab Personal Choice Retirement Account    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 448,209,000 399,055,000
Master Trust Balances | Level 2    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 3,028,000 2,591,000
Master Trust Balances | Level 2 | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 2 | HII common stock    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 2 | Collective trust funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 2 | Schwab Personal Choice Retirement Account    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 3,028,000 2,591,000
Master Trust Balances | Level 3    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 3 | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 3 | HII common stock    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 3 | Collective trust funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | Level 3 | Schwab Personal Choice Retirement Account    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | NAV    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 5,842,490,000 5,062,234,000
Master Trust Balances | NAV | Short-term investment funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 21,639,000 21,658,000
Master Trust Balances | NAV | HII common stock    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 0 0
Master Trust Balances | NAV | Collective trust funds    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust 5,820,851,000 5,040,576,000
Master Trust Balances | NAV | Schwab Personal Choice Retirement Account    
EBP, Master Trust [Line Items]    
Total assets in the DC Master Trust $ 0 $ 0