v3.22.0.1
Segment and Related Information​ - Operating Results and Assets (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended 12 Months Ended
Dec. 31, 2021
Sep. 30, 2021
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Segment Reporting Information [Line Items]          
Total sales     $ 7,504 $ 5,675 $ 7,277
Provision for depreciation and amortization     253 251 252
Assets $ 6,580   6,580 6,314  
Capital expenditures 2,651   2,651 2,712  
Goodwill 322   322 390 386
Rolled Products          
Segment Reporting Information [Line Items]          
Goodwill 253 $ 254 253 254 246
Inventory Write-down 10 7      
Building and Construction Systems          
Segment Reporting Information [Line Items]          
Goodwill 69 70 69 71 69
Extrusions          
Segment Reporting Information [Line Items]          
Goodwill 0 $ 65 0 65 71
External Sales Including Reconciling Items          
Segment Reporting Information [Line Items]          
Total sales     7,504 5,679 7,277
External Sales Including Reconciling Items | Rolled Products          
Segment Reporting Information [Line Items]          
Total sales     6,187 4,335 5,609
External Sales Including Reconciling Items | Building and Construction Systems          
Segment Reporting Information [Line Items]          
Total sales     1,011 963 1,118
External Sales Including Reconciling Items | Extrusions          
Segment Reporting Information [Line Items]          
Total sales     306 381 550
Elimination of intersegment sales          
Segment Reporting Information [Line Items]          
Total sales     (34) (21) (28)
Elimination of intersegment sales | Rolled Products          
Segment Reporting Information [Line Items]          
Total sales     (33) (19) (25)
Elimination of intersegment sales | Building and Construction Systems          
Segment Reporting Information [Line Items]          
Total sales     0 0 0
Elimination of intersegment sales | Extrusions          
Segment Reporting Information [Line Items]          
Total sales     (1) (2) (3)
Segment total          
Segment Reporting Information [Line Items]          
Total sales     7,538 5,700 7,305
Segment Adjusted EBITDA     757 648 757
Provision for depreciation and amortization     237 235 232
Assets 5,563   5,563 4,696  
Segment total | Rolled Products          
Segment Reporting Information [Line Items]          
Total sales     6,220 4,354 5,634
Segment Adjusted EBITDA     655 527 640
Provision for depreciation and amortization     197 192 185
Assets 4,766   4,766 3,895  
Segment total | Building and Construction Systems          
Segment Reporting Information [Line Items]          
Total sales     1,011 963 1,118
Segment Adjusted EBITDA     130 137 126
Provision for depreciation and amortization     17 18 18
Assets 416   416 381  
Segment total | Extrusions          
Segment Reporting Information [Line Items]          
Total sales     307 383 553
Segment Adjusted EBITDA     (28) (16) (9)
Provision for depreciation and amortization     23 25 29
Assets 381   381 420  
Supplemental Information          
Segment Reporting Information [Line Items]          
Total sales     0 (4) $ 0
Capital expenditures 172   172 152  
Goodwill 322   322 390  
Supplemental Information | Rolled Products          
Segment Reporting Information [Line Items]          
Capital expenditures 147   147 134  
Goodwill 253   253 254  
Supplemental Information | Building and Construction Systems          
Segment Reporting Information [Line Items]          
Capital expenditures 11   11 7  
Goodwill 69   69 71  
Supplemental Information | Extrusions          
Segment Reporting Information [Line Items]          
Capital expenditures 14   14 11  
Goodwill $ 0   $ 0 $ 65