XML 56 R47.htm IDEA: XBRL DOCUMENT v3.24.1.u1
Earnings Per Share - Schedule of Computation of Basic and Diluted EPS Attributable to Alcoa Corporation Common Shareholders (Detail) - USD ($)
shares in Millions, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2024
Mar. 31, 2023
Dec. 31, 2023
Earnings Per Share [Abstract]      
Net Income (Loss) $ (252) $ (231) $ (231)
Average shares outstanding – basic 179 178  
Effect of dilutive securities:      
Average shares outstanding – diluted 179 178