v3.20.2
Acquisitions and Divestitures (Details)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Mar. 01, 2020
USD ($)
employee
Feb. 01, 2020
USD ($)
employee
Jun. 30, 2020
USD ($)
Dec. 31, 2019
USD ($)
Jun. 30, 2019
USD ($)
Jun. 30, 2020
USD ($)
Jun. 30, 2019
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Total Sales     $ 1,187   $ 1,923 $ 2,798 $ 3,764      
Disposed of by sale | Aluminum Rolling Mill in Itapissuma, Brazil                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Consideration received   $ 46                
Gain (loss) on sale   $ (59)                
Sale transaction costs     6 $ 53            
Total Sales               $ 143 $ 179 $ 162
Number of employees | employee   500                
Disposed of by sale | Hard Alloy Extrusions Plant in South Korea                    
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]                    
Consideration received $ 55                  
Gain (loss) on sale 31   $ 1              
Write-off of goodwill $ 6                  
Total Sales               $ 51 $ 53 $ 50
Number of employees | employee 160