v3.26.1
Organization and basis of presentation - Narrative (Details)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
segment
shares
Jun. 30, 2025
USD ($)
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
shares
Jun. 23, 2025
shares
Dec. 31, 2024
USD ($)
Business Combination [Line Items]              
Number of reportable segments | segment   2          
Common stock, outstanding (in shares) | shares   549,779,621     553,082,525 566,875,513  
Treasury stock (in shares) | shares   17,095,892     13,792,988 13,793,444  
Contract liabilities | $ $ 462 $ 488 $ 462   $ 519   $ 477
Revision of Prior Period, Adjustment              
Business Combination [Line Items]              
Contract liabilities | $       $ 76 $ 78    
Related Party              
Business Combination [Line Items]              
Various transaction costs | $ $ 6   $ 11        
Holcim Ltd | Amrize Ltd | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff              
Business Combination [Line Items]              
Equity interest disposed           100.00%  
Number of shares issued (in shares) | shares           553,082,069