v3.20.1
Contingencies and Commitments​ (Details)
1 Months Ended 3 Months Ended
Jun. 06, 2019
plaintiff
Sep. 15, 2017
executive
Jun. 30, 2019
USD ($)
Mar. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Site Contingency [Line Items]          
Environmental remediation       $ 208,000,000  
Environmental remediation, current       81,000,000 $ 83,000,000
Environmental remediation, additions       1  
Environmental remediation, payments       2,000,000  
Environmental remediation, foreign currency translation       1  
Behrens v. Arconic          
Site Contingency [Line Items]          
Number of plaintiffs | plaintiff 247        
Sullivan v. Arconic          
Site Contingency [Line Items]          
Number of former executives | executive   3      
Massena West, NY          
Site Contingency [Line Items]          
Environmental remediation       $ 170,000,000 $ 171,000,000
Environmental remediation, additions     $ 25,000,000