Restructuring and Other Charges - 2014 Actions - Additional Information (Detail) € in Millions, $ in Millions	1 Months Ended				3 Months Ended	12 Months Ended
	Aug. 31, 2014 t	Jun. 30, 2014 t	May. 31, 2014 t	May. 31, 2013 t	Dec. 31, 2015 USD ($) Employees	Dec. 31, 2015 EUR (€) Employees t	Dec. 31, 2015 USD ($) Employees t	Dec. 31, 2014 USD ($) Employees Facilities t	Dec. 31, 2013 USD ($) Employees
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges					$ 735	€ 150	$ 1,195	$ 1,168	$ 782
Restructuring and other charges, after-tax and noncontrolling interest					$ 507		$ 836	$ 703	$ 585
Number of employees associated with layoff costs | Employees								1,120	1,110
Capacity of lines under review | t				460,000		2,800,000	2,800,000
Capacity of lines under review period				15 months		12 months	12 months
Accelerated depreciation									$ 58
Asset impairment charges							$ 335	$ 406	116
Inventory write-down - permanent shutdown and planned demolition of idled structures							90
Inventory write-down, after-tax and non-controlling interests							43
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							83	$ 39	$ 433
Transportation and Construction Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees									75
Engineered Products and Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees								470	220
Global Rolled Products [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees								45	250
Alumina and Primary Metals Segments [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees								60
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees								185	140
Primary Metals [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees									340
Alumina [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees									85
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]
Reduction in production - result of market conditions, in mt per year | t								190,000
Pocos de Caldas Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Capacity of lines under review | t		200,000	62,000
Sao Luis Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Capacity of lines under review | t			85,000
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
Other Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							438	$ 693	$ 245
Restructuring and other charges, after-tax and noncontrolling interest							281	443	183
Divested Businesses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges								332
Restructuring and other charges, after-tax and noncontrolling interest								163
Divested Businesses [Member] | Global Rolled Products [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							161
Restructuring and other charges, after-tax and noncontrolling interest							151
Temporary Curtailment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges								68
Restructuring and other charges, after-tax and noncontrolling interest								45
Layoff Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							$ 156	51	87
Restructuring and other charges, after-tax and noncontrolling interest								36	61
Restructuring Programs Layoffs 2014 [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions separated | Employees						2,100	2,100
Cash payments made against the layoff reserves							$ 62	$ 141
Restructuring Programs Layoffs 2014 [Member] | Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions separated | Employees						475	475
Restructuring Programs Layoffs 2014 [Member] | Transportation and Construction Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees								360
Number of positions separated | Employees						425	425
Restructuring Programs Layoffs 2014 [Member] | Engineered Products and Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions separated | Employees						645	645
Restructuring Programs Layoffs 2014 [Member] | Global Rolled Products [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions separated | Employees						90	90
Restructuring Programs Layoffs 2014 [Member] | Primary Metals [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions separated | Employees						380	380
Restructuring Programs Layoffs 2014 [Member] | Alumina [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions separated | Employees						85	85
Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges								$ 34	3
Restructuring and other charges, after-tax and noncontrolling interest								26	2
Other Miscellaneous Items [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							$ 4	18	17
Restructuring and other charges, after-tax and noncontrolling interest							7	11	12
Asset Impairment and Accelerated Depreciation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							84	2
Restructuring and other charges, after-tax and noncontrolling interest								2
Small Layoff Reserves Related to Prior Periods [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges								28
Restructuring and other charges, after-tax and noncontrolling interest								21
Shutdown and Curtailment Actions [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							246	$ 208
Restructuring and other charges, after-tax and noncontrolling interest							$ 118
Number of employees associated with layoff costs | Employees						3,100	3,100	1,790
Accelerated depreciation								$ 204
Asset impairment charges							$ 217	166
Amount of book value of asset write off								183
Inventory write-down - permanent shutdown and planned demolition of idled structures								67
Inventory write-down, after-tax and non-controlling interests								$ 47
Shutdown and Curtailment Actions [Member] | Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees								30
Shutdown and Curtailment Actions [Member] | Global Rolled Products [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees								470
Shutdown and Curtailment Actions [Member] | Primary Metals [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						1,800	1,800	1,210
Shutdown and Curtailment Actions [Member] | Alumina [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						1,300	1,300	80
Shutdown and Curtailment Actions [Member] | Australia [Member]
Restructuring Cost and Reserve [Line Items]
Number of facilities accelerated depreciation write off | Facilities								3
Asset impairment charges							$ 34
Pension Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							30	$ 26
Asset Retirement Obligations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							76	95	58
Other exit costs								95	48
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							86	47	12
Other exit costs								42	5
Supplier and Customer Contract [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							$ 65
Other exit costs								$ 46	2
Restructuring Programs Layoffs 2013 [Member]
Restructuring Cost and Reserve [Line Items]
Total number of employees already laid off | Employees					2,870	2,870	2,870
Number of positions separated | Employees						2,500	2,500	2,910
Cash payments made against the layoff reserves							$ 7	$ 39	$ 33