v3.26.1
Discontinued Operations - Narrative (Details) - USD ($)
$ in Thousands
 1 Months Ended 3 Months Ended 9 Months Ended
Apr. 30, 2025
Apr. 10, 2025
Apr. 07, 2025
Mar. 13, 2025
Sep. 27, 2024
Apr. 26, 2019
Mar. 31, 2025
Feb. 28, 2025
Jun. 26, 2026
Jun. 27, 2025
Mar. 28, 2025
Jun. 26, 2026
Jun. 27, 2025
Sep. 26, 2025
Disposal Group, Including Discontinued Operations [Line Items]                            
Investment in equity securities                 $ 6,198     $ 6,198   $ 0
Miscellaneous income (expense), net                 890 $ 38,844   (16,480) $ (194,523)  
(Gain) loss on investment in equity securities                   (27,400)   (6,198) 227,305  
Transition services agreement, expenses incurred                 $ 0 (9,800)   0 (31,500)  
Worley Stock                            
Disposal Group, Including Discontinued Operations [Line Items]                            
Business combination consideration equity issued           $ 58,200                
Worley                            
Disposal Group, Including Discontinued Operations [Line Items]                            
Consideration transferred           3,400,000                
Consideration paid in cash           $ 2,800,000                
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff | Amentum Holdings, Inc.                            
Disposal Group, Including Discontinued Operations [Line Items]                            
Discontinued operation, remaining shares held in escrow (in shares)     9,700,000                      
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff | SpinCo Business                            
Disposal Group, Including Discontinued Operations [Line Items]                            
Stock issued during period, spinoff transaction ( in shares)         124,084,108                  
Shares issued during period, spinoff, conversion ratio (in shares)         1                  
Cash received from SpinCo business         $ 911,000                  
Discontinued operation, working capital adjustment             $ 70,000              
Discontinued operation, working capital adjustment, reduction in recorded receivable             $ 24,000              
Discontinued operation, receivable balance collected   $ 70,000                        
Discontinued net cash flows from operating activities                   $ (2,400)   $ (32,700) $ (2,400)  
Discontinued operation, remaining shares held in escrow (in shares) 7,300,000   7,300,000                      
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff | SpinCo Business | Amentum Holdings, Inc.                            
Disposal Group, Including Discontinued Operations [Line Items]                            
Equity method investment retained, shares owned after disposal (in shares)         29,200,000                  
Equity method investment retained, shares transferred to escrow (in shares)         10,900,000                  
Discontinued operation, remaining shares held in escrow (in shares)     2,400,000 9,700,000 18,300,000                  
Investment in equity securities         $ 749,500                  
Discontinued operation, entitled to receive shares held in escrow (in shares)               1,200,000            
Miscellaneous income (expense), net                     $ 21,900