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Restructuring and Other Charges - Additional Information (Detail) $ in Millions |  | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Jun. 30, 2015 Employees | Aug. 31, 2014 | Jun. 30, 2014 t | May. 31, 2014 t | May. 31, 2013 t | Jun. 30, 2015 USD ($) Employees t | Jun. 30, 2014 USD ($) Employees Plant Facilities | Mar. 31, 2014 t | Jun. 30, 2015 USD ($) Employees t | Jun. 30, 2014 USD ($) Employees Plant Facilities | Dec. 31, 2014 Employees
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 217 | $ 110 |  | $ 394 | $ 571 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | $ 141 | $ 54 |  | $ 299 | $ 328 |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 390 | 75 |  | 600 |  |
Capacity of lines under review | t |  |  |  |  | 460,000 |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 245 |
Capacity of lines under review period |  |  |  |  | 15 months |  |  |  |  |  |
Minimum amount of cash payments expected to be paid beyond the end of the current annual period |  |  |  |  |  |  |  |  | $ 20 |  |
Maximum amount of cash payments expected to be paid beyond the end of the current annual period |  |  |  |  |  |  |  |  | 25 |  |
Corporate [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 24 | $ 3 |  | $ 29 | $ 32 |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  | 30 |  | 50 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 90 |
Firth Rixson [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | 10 |  |  |  |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | $ 7 |  |  |  |  |
Smelter [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of plants permanently shut down and demolished | Plant |  |  |  |  |  |  | 2 |  |  | 2 |
Number of plants temporarily curtailed | Plant |  |  |  |  |  |  |  |  |  | 2 |
Rolling Mill [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of plants permanently shut down and demolished | Plant |  |  |  |  |  |  | 2 |  |  | 2 |
Global Rolled Products [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 30 | 30 |  | 60 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 30 |
Other Segments [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  | 15 |  |  |  |
Primary Metals [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 150 |  |  | 150 |  |
Alumina [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 10 |
Engineered Products and Solutions [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 210 |  |  | 340 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 115 |
Massena East Smelter [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Reduction in production - result of market conditions, in mt per year | t |  |  |  |  |  |  |  | 84,000 |  |  |
Point Henry Smelter [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Power supplied as percentage of plant total power requirement |  | 40.00% |  |  |  |  |  |  |  |  |
Reduction in production - result of market conditions, in mt per year | t |  |  |  |  |  |  |  | 190,000 |  |  |
Pocos De Caldas Refinery [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Capacity of lines under review | t |  |  | 200,000 | 62,000 |  |  |  |  |  |  |
Reduction in production - result of market conditions, in mt per year | t |  |  |  |  |  |  |  |  | 96,000 |  |
Sao Luis Smelter [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  | $ 16 |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  | $ 13 |  |
Capacity of lines under review | t |  |  |  | 85,000 |  |  |  |  | 74,000 |  |
Sao Luis Smelter [Member] | Primary Metals [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  | 680 |  |
Massena East, Ny and Point Henry and Yennora, Australia and Portovesme [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Reduction in production - result of market conditions, in mt per year | t |  |  |  |  |  |  |  | 200,000 |  |  |
Suriname [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Capacity of lines under review | t |  |  |  |  |  | 443,000 |  |  |  |  |
Suriname [Member] | Alumina [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 120 |  |  | 120 |  |
Sao Luis Smelter and Suriname [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  | 800 |  |
Other Exit Costs [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 179 | $ 107 |  | $ 179 | $ 443 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 115 | 51 |  | 115 | 240 |
Other Miscellaneous Items [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | 5 | 3 |  | 3 | 17 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 3 | 3 |  | 2 | 11 |
Shutdown And Curtailment Actions [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  | $ 4 |  |  | $ 137 |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  | 1,830 |  |  | 1,830 |
Other asset impairment charges |  |  |  |  |  |  |  |  |  | $ 91 |
Other exit costs |  |  |  |  |  |  | $ 10 |  |  | 133 |
Inventory write-down - permanent shutdown and planned demolition of idled structures |  |  |  |  |  |  |  |  |  | 34 |
Inventory write-down, after-tax and non-controlling interests |  |  |  |  |  |  |  |  |  | 20 |
Accelerated depreciation |  |  |  |  |  |  | $ 91 |  |  | $ 150 |
Shutdown And Curtailment Actions [Member] | Corporate [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  | 40 |  |  | 40 |
Shutdown And Curtailment Actions [Member] | Global Rolled Products [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  | 470 |  |  | 470 |
Shutdown And Curtailment Actions [Member] | Primary Metals [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  | 1,230 |  |  | 1,230 |
Shutdown And Curtailment Actions [Member] | Alumina [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  | 90 |  |  | 90 |
Shutdown And Curtailment Actions [Member] | Australia [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of facilities accelerated depreciation write off | Facilities |  |  |  |  |  |  | 3 |  |  | 3 |
Asset Retirement Obligations [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  | 45 | $ 95 |
Other exit costs |  |  |  |  |  | 45 |  |  | 45 | 55 |
Environmental Remediation [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  | 29 | 47 |
Other exit costs |  |  |  |  |  | 29 |  |  | 29 | 38 |
Supplier And Customer Contract [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other exit costs |  |  |  |  |  | 11 |  |  | 8 | 40 |
Shutdown Costs [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other asset impairment charges |  |  |  |  |  | 86 |  |  | 86 |  |
Other exit costs |  |  |  |  |  | 82 |  |  | 82 |  |
Inventory write-down - permanent shutdown and planned demolition of idled structures |  |  |  |  |  | 4 |  |  | 4 |  |
Inventory write-down, after-tax and non-controlling interests |  |  |  |  |  | 2 |  |  | 2 |  |
Shutdown Costs [Member] | Primary Metals [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 11 |  |  | $ 11 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 100 |  |  | 100 |  |
Smelter Curtailments [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  |  | 68 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  |  | $ 44 |
Smelter Curtailments [Member] | Refinery [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of plants temporarily curtailed | Plant |  |  |  |  |  |  |  |  |  | 1 |
Asset Impairment [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  |  | $ 33 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  |  | 26 |
Layoff Costs [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  | $ 38 | 17 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  | 23 | 11 |
Layoff Costs [Member] | Suriname [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 18 |  |  |  |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 10 |  |  |  |  |
Small Layoff Reserves Related to Prior Periods [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | 1 |  |  | 8 | 7 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | $ 1 |  |  | $ 7 | $ 4 |
Restructuring Programs Layoffs 2015 [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total number of employees already laid off | Employees | 730 |  |  |  |  | 730 |  |  | 730 |  |
Number of positions separated | Employees | 1,500 |  |  |  |  |  |  |  |  |  |
Cash payments made against the layoff reserves |  |  |  |  |  | $ 14 |  |  | $ 15 |  |
Restructuring Programs Layoffs 2014 [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total number of employees already laid off | Employees | 2,460 |  |  |  |  | 2,460 |  |  | 2,460 |  |
Number of positions separated | Employees | 2,870 |  |  |  |  |  |  |  |  |  | 2,910
Cash payments made against the layoff reserves |  |  |  |  |  | $ 6 |  |  | $ 56 |  |
Restructuring Programs Layoffs 2013 [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total number of employees already laid off | Employees | 1,460 |  |  |  |  | 1,460 |  |  | 1,460 |  |
Number of positions separated | Employees | 1,530 |  |  |  |  |  |  |  |  |  |
Cash payments made against the layoff reserves |  |  |  |  |  | $ 2 |  |  | $ 5 |  |
Divested Businesses [Member] | Russia [Member] |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  | 159 |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  | $ 149 |  |

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