v3.26.1
Investments (Tables)
 12 Months Ended
Dec. 31, 2025
EBP 022  
EBP, Master Trust [Line Items]  
Schedule of Master Trust Net Assets
The following table is a summary, at fair value, of the net assets of the master trust by investment type as of December 31, 2025 and 2024: 
20252024
Master Trust BalancesPlan's Interest in Master Trust BalancesMaster Trust BalancesPlan's Interest in Master Trust Balances
Allegheny Technologies Incorporated Master Trust:
Common collective trusts$681,459,280 $488,205,426 $611,412,373 $436,969,150 
Registered investment companies452,989,632 353,919,826 385,843,440 308,457,426 
Pooled separate accounts151,624,798 108,253,247 140,662,433 103,333,576 
Corporate common stock93,113,165 57,940,871 68,021,722 39,494,063 
Cash4,805,431 3,015,662 3,451,804 2,211,493 
Total investments at fair value$1,383,992,306 $1,011,335,032 $1,209,391,772 $890,465,708 
Plan's interest in master trust73 %74 %
The following table is a summary, at contract value, of the net assets of the Allegheny Technologies Incorporated Master Trust by investment type as of December 31, 2025 and 2024: 
20252024
Master Trust BalancesPlan's Interest in Master Trust BalancesMaster Trust BalancesPlan's Interest in Master Trust Balances
Allegheny Technologies Incorporated Master Trust:
Synthetic investment contracts$113,818,599 $71,427,188 $120,666,597 $77,458,294 
Total investments held at contract value$113,818,599 $71,427,188 $120,666,597 $77,458,294 

Investment income attributable to the master trust for the year ended December 31, 2025 was as follows: 
Allegheny Technologies Incorporated Master Trust
Net appreciation in fair value of investments$235,511,834 
Investment income from investments at fair value14,683,788 
Investment income from investments at contract value3,532,110 
Administrative expenses and other, net(115,396)
Total investment income $253,612,336