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Restructuring and Other Charges - Additional Information (Detail) |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended
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Sep. 30, 2015 Employees | Aug. 31, 2014 | Jun. 30, 2014 t | May. 31, 2014 t | May. 31, 2013 t | Sep. 30, 2015 USD ($) Employees t | Jun. 30, 2015 t | Sep. 30, 2014 USD ($) Employees Plant Facilities t | Mar. 31, 2014 t | Sep. 30, 2015 USD ($) Employees t | Sep. 30, 2014 USD ($) Employees Plant Facilities | Dec. 31, 2014 Employees
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 66,000,000 |  | $ 209,000,000 |  | $ 460,000,000 | $ 780,000,000 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | $ 30,000,000 |  | 175,000,000 |  | $ 329,000,000 | $ 503,000,000 |
Capacity of lines under review | t |  |  |  |  | 460,000 |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 370 |  |  |  | 970 |  |
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 |  |  |  |  |  |  |  |  |  | $ 50,000,000 |  |
Maximum amount of cash payments expected to be paid beyond the end of the current annual period |  |  |  |  |  |  |  |  |  | 55,000,000 |  |
Corporate [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 9,000,000 |  | $ 2,000,000 |  | $ 38,000,000 | $ 34,000,000 |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 50 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  |  | 90 |
Smelter [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of plants permanently shut down and demolished | Plant |  |  |  |  |  |  |  | 2 |  |  | 3 |
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 |
Primary Metals [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  |  | $ 80,000,000 |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  |  | $ 43,000,000 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 165 |  |
Global Rolled Products [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 70 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  |  | 30 |
Alumina [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  |  | 10 |
Transportation and Construction Solutions [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 355 |  |  |  | 410 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  |  | 50 |
Corporate and Three Other Segments [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  | 15 |  |  |  |  |  |
Engineered Products and Solutions [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 275 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  |  | 65 |
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] |  |  |  |  |  |  |  |  |  |  |  |
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 |  |
Suriname [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 42,000,000 |  |  |  |  |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | $ 20,000,000 |  |  |  |  |  |
Capacity of lines under review | t |  |  |  |  |  | 887,000 |  |  |  | 1,330,000 |  |
Suriname [Member] | Alumina [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 120 |  |
Sao Luis Smelter and Suriname [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 800 |  |
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 |  |  |
Massena East Smelter [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Reduction in production - result of market conditions, in mt per year | t |  |  |  |  |  |  |  |  | 84,000 |  |  |
Massena East Ny And Point Henry And Yennora [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Reduction in production - result of market conditions, in mt per year | t |  |  |  |  |  |  |  |  | 200,000 |  |  |
Portovesme [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Capacity of lines under review | t |  |  |  |  |  |  |  | 150,000 |  |  |  |
Shutdown And Curtailment Actions [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  | $ 60,000,000 |  |  | $ 197,000,000 |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  | 1,780 |  |  | 1,780 |
Asset impairment charges |  |  |  |  |  |  |  | $ 74,000,000 |  |  | $ 165,000,000 |
Inventory write-down - permanent shutdown and planned demolition of idled structures |  |  |  |  |  |  |  | 33,000,000 |  |  | 67,000,000 |
Inventory write-down, after-tax and non-controlling interests |  |  |  |  |  |  |  | 27,000,000 |  |  | 47,000,000 |
Accelerated depreciation |  |  |  |  |  |  |  | 40,000,000 |  |  | 190,000,000 |
Amount of book value of asset write off |  |  |  |  |  |  |  | $ 45,000,000 |  |  | $ 178,000,000 |
Shutdown And Curtailment Actions [Member] | Corporate [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  | 30 |  |  | 30 |
Shutdown And Curtailment Actions [Member] | Primary Metals [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  | 1,200 |  |  | 1,200 |
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] | Alumina [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  | 80 |  |  | 80 |
Shutdown And Curtailment Actions [Member] | Australia [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of facilities accelerated depreciation write off | Facilities |  |  |  |  |  |  |  | 3 |  |  | 3 |
Pension Costs [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  | $ 18,000,000 |  | $ 11,000,000 | $ 18,000,000 |
Asset Retirement Obligations [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  |  | 45,000,000 | 95,000,000 |
Other exit costs |  |  |  |  |  |  |  | 40,000,000 |  | 45,000,000 | 95,000,000 |
Environmental Remediation [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  |  | 29,000,000 | 47,000,000 |
Other exit costs |  |  |  |  |  |  |  | 4,000,000 |  | 29,000,000 | 42,000,000 |
Supplier And Customer Contract [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other exit costs |  |  |  |  |  |  |  | 1,000,000 |  | 8,000,000 | 41,000,000 |
Layoff Costs [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 33,000,000 |  |  |  | 62,000,000 | 18,000,000 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 29,000,000 |  |  |  | 50,000,000 | 11,000,000 |
Gain on Sale of Discontinued Operations [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  | 5,000,000 |  |  |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  | 4,000,000 |  |  |  |
Gain on Sale of Discontinued Operations [Member] | Australia [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | 18,000,000 |  |  |  | 18,000,000 |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 13,000,000 |  |  |  | 13,000,000 |  |
Other Exit Costs [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | 11,000,000 |  | 220,000,000 |  | 190,000,000 | 663,000,000 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 5,000,000 |  | 186,000,000 |  | 120,000,000 | 426,000,000 |
Other Miscellaneous Items [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | 2,000,000 |  | 4,000,000 |  | 3,000,000 | 16,000,000 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 9,000,000 |  | 2,000,000 |  | 13,000,000 | 9,000,000 |
Small Layoff Reserves Related to Prior Periods [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | 4,000,000 |  |  |  | 12,000,000 |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  | 2,000,000 |  |  |  | 9,000,000 |  |
Divested Businesses [Member] | Russia [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  |  | 161,000,000 |  |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  |  | 151,000,000 |  |
Shutdown Costs [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Asset impairment charges |  |  |  |  |  |  |  |  |  | 86,000,000 |  |
Other exit costs |  |  |  |  |  |  |  |  |  | 82,000,000 |  |
Inventory write-down - permanent shutdown and planned demolition of idled structures |  |  |  |  |  |  |  |  |  | 4,000,000 |  |
Inventory write-down, after-tax and non-controlling interests |  |  |  |  |  |  |  |  |  | 2,000,000 |  |
Shutdown Costs [Member] | Primary Metals [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  | $ 11,000,000 |  |  |  | $ 22,000,000 |  |
Number of employees associated with layoff costs | Employees |  |  |  |  |  |  |  |  |  | 90 |  |
Layoff Reserves Related to Prior Periods [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  | 10,000,000 |  |  | 17,000,000 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  | $ 9,000,000 |  |  | 13,000,000 |
Smelter Curtailments [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring and other charges |  |  |  |  |  |  |  |  |  |  | 67,000,000 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  |  |  | $ 44,000,000 |
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 |  |  |  |  |  |  |  |  |  |  | $ 33,000,000 |
Restructuring and other charges, after-tax and noncontrolling interest |  |  |  |  |  |  |  |  |  |  | $ 26,000,000 |
Restructuring Programs Layoffs 2015 [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Approximate number of employees already laid off | Employees | 1,240 |  |  |  |  | 1,240 |  |  |  | 1,240 |  |
Number of positions separated | Employees | 1,860 |  |  |  |  |  |  |  |  |  |  |
Cash payments made against the layoff reserves |  |  |  |  |  | $ 19,000,000 |  |  |  | $ 34,000,000 |  |
Restructuring Programs Layoffs 2014 [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Approximate number of employees already laid off | Employees | 2,500 |  |  |  |  | 2,500 |  |  |  | 2,500 |  |
Number of positions separated | Employees | 2,870 |  |  |  |  |  |  |  |  |  |  | 2,910
Cash payments made against the layoff reserves |  |  |  |  |  | $ 4,000,000 |  |  |  | $ 60,000,000 |  |
Restructuring Programs Layoffs 2013 [Member] |  |  |  |  |  |  |  |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Approximate number of employees already laid off | Employees | 1,480 |  |  |  |  | 1,480 |  |  |  | 1,480 |  |
Number of positions separated | Employees | 1,530 |  |  |  |  |  |  |  |  |  |  |
Cash payments made against the layoff reserves |  |  |  |  |  | $ 1,000,000 |  |  |  | $ 6,000,000 |  |

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- Definition The maximum amount of cash payments expected to be paid beyond the end of the current annual period related to restructuring charges such as ongoing site remediation work, special termination benefit payments, least termination costs, among others. + References No definition available. + Details
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- Definition The minimum amount of cash payments expected to be paid beyond the end of the current annual period related to restructuring charges such as ongoing site remediation work, special termination benefit payments, least termination costs, among others. + References No definition available. + Details
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