Restructuring and Other Charges - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended					3 Months Ended	6 Months Ended	3 Months Ended				6 Months Ended	3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended		12 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended	3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended	3 Months Ended		6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Mar. 31, 2014 t	Jun. 30, 2013 Employees t Location	Jun. 30, 2014 Employees t	Jun. 30, 2013 Location Employees	Jun. 30, 2013 Global Rolled Products [Member] Employees	Jun. 30, 2014 Global Rolled Products [Member] Employees	Jun. 30, 2013 Global Rolled Products [Member] Employees	Jun. 30, 2013 Primary Metals [Member] Employees	Jun. 30, 2014 Primary Metals [Member] Employees	Jun. 30, 2013 Primary Metals [Member] Employees	Jun. 30, 2013 Engineered Products and Solutions [Member] Employees	Jun. 30, 2014 Engineered Products and Solutions [Member] Employees	Jun. 30, 2013 Engineered Products and Solutions [Member] Employees	Jun. 30, 2014 Global Rolled Products Segment [Member] Employees	Jun. 30, 2014 Alumina and Primary Metals Segments [Member] Employees	Jun. 30, 2014 Alumina [Member] Employees	Jun. 30, 2013 Baie Comeau [Member] t Potline	Jun. 30, 2013 Baie Comeau [Member]	Jun. 30, 2013 Quebec Canada [Member] t	Jun. 30, 2013 Fusina Italy [Member] t	Mar. 31, 2014 Fusina and Massena East [Member] t	Jun. 30, 2013 Fusina and Massena East [Member]	Jun. 30, 2013 Fusina and Massena East [Member]	Mar. 31, 2014 Point Henry Smelter [Member] t	Jun. 30, 2014 Pocos De Caldas Refinery [Member] t	Jun. 30, 2014 Australia [Member] Facilities	Jun. 30, 2014 Other Exit Costs [Member]	Jun. 30, 2013 Other Exit Costs [Member]	Jun. 30, 2014 Other Exit Costs [Member]	Jun. 30, 2013 Legal Matter [Member]	Jun. 30, 2013 Legal Matter [Member]	Jun. 30, 2013 Asset Impairment [Member]	Jun. 30, 2014 Asset Impairment [Member]	Jun. 30, 2013 Layoff Costs [Member]	Jun. 30, 2014 Layoff Costs [Member]	Jun. 30, 2013 Layoff Costs [Member]	Jun. 30, 2014 Layoff Costs [Member] Primary Metals [Member]	Jun. 30, 2014 Layoff Costs [Member] Primary Metals [Member]	Jun. 30, 2014 Other Miscellaneous Items [Member]	Jun. 30, 2013 Other Miscellaneous Items [Member]	Jun. 30, 2014 Other Miscellaneous Items [Member]	Jun. 30, 2013 Other Miscellaneous Items [Member]	Jun. 30, 2013 Small Layoff Reserves Related to Prior Periods [Member]	Jun. 30, 2014 Small Layoff Reserves Related to Prior Periods [Member]	Jun. 30, 2013 Small Layoff Reserves Related to Prior Periods [Member]	Jun. 30, 2014 Permanent Shutdown and Planned Demolition of Idled Structures [Member]	Jun. 30, 2013 Permanent Shutdown and Planned Demolition of Idled Structures [Member]	Jun. 30, 2014 Permanent Shutdown and Planned Demolition of Idled Structures [Member]	Jun. 30, 2013 Permanent Shutdown and Planned Demolition of Idled Structures [Member]	Jun. 30, 2013 Operating Supplies [Member]	Jun. 30, 2014 Operating Supplies [Member]	Jun. 30, 2013 Operating Supplies [Member]	Jun. 30, 2013 Asset Retirement Obligations [Member]	Jun. 30, 2014 Asset Retirement Obligations [Member]	Jun. 30, 2013 Asset Retirement Obligations [Member]	Dec. 31, 2013 Asset Retirement Obligations [Member]	Jun. 30, 2013 Environmental Remediation [Member]	Jun. 30, 2014 Environmental Remediation [Member]	Jun. 30, 2013 Environmental Remediation [Member]	Dec. 31, 2013 Environmental Remediation [Member]	Jun. 30, 2014 Smelter Curtailments [Member] Employees	Jun. 30, 2014 Smelter Curtailments [Member] Employees	Jun. 30, 2014 Supplier And Customer Contract [Member]	Jun. 30, 2014 Restructuring Programs Layoffs 2014 [Member] Employees	Jun. 30, 2014 Restructuring Programs Layoffs 2014 [Member] Employees	Jun. 30, 2014 Restructuring Programs Layoffs 2013 [Member] Employees	Jun. 30, 2014 Restructuring Programs Layoffs 2013 [Member] Employees	Jun. 30, 2014 Corporate [Member] Employees	Jun. 30, 2013 Corporate [Member] Employees	Jun. 30, 2014 Corporate [Member] Employees	Jun. 30, 2013 Corporate [Member] Employees	Jun. 30, 2014 Operating Segments [Member]	Jun. 30, 2013 Operating Segments [Member]	Jun. 30, 2014 Operating Segments [Member]	Jun. 30, 2013 Operating Segments [Member]	Jun. 30, 2014 Operating Segments [Member] Global Rolled Products [Member]	Jun. 30, 2013 Operating Segments [Member] Global Rolled Products [Member]	Jun. 30, 2014 Operating Segments [Member] Global Rolled Products [Member]	Jun. 30, 2013 Operating Segments [Member] Global Rolled Products [Member]	Jun. 30, 2014 Operating Segments [Member] Primary Metals [Member]	Jun. 30, 2013 Operating Segments [Member] Primary Metals [Member]	Jun. 30, 2014 Operating Segments [Member] Primary Metals [Member]	Jun. 30, 2013 Operating Segments [Member] Primary Metals [Member]	Jun. 30, 2013 Operating Segments [Member] Engineered Products and Solutions [Member]	Jun. 30, 2014 Operating Segments [Member] Engineered Products and Solutions [Member]	Jun. 30, 2013 Operating Segments [Member] Engineered Products and Solutions [Member]	Jun. 30, 2014 Operating Segments [Member] Global Rolled Products Segment [Member] Employees	Jun. 30, 2014 Operating Segments [Member] Other Segments [Member] Employees	Jun. 30, 2014 Operating Segments [Member] Alumina [Member]	Jun. 30, 2014 Rolling Mill [Member] Plant	Mar. 31, 2014 Rolling Mill [Member] Plant	Jun. 30, 2014 Rolling Mill [Member] Plant	Jun. 30, 2014 Smelter [Member] Plant	Jun. 30, 2014 Smelter [Member] Plant	Jun. 30, 2014 Refinery [Member] Smelter Curtailments [Member] Plant
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 110		$ 244	$ 571	$ 251																							$ 107	$ 86	$ 443	$ 103	$ 218	$ 29	$ 33	$ 24	$ 17	$ 27	$ 4	$ 137	$ 3	$ 4	$ 17	$ 8	$ 2	$ 7	$ 2									$ 55		$ 58		$ 42		$ 12		$ 68						$ 3	$ 124	$ 32	$ 125	$ 107	$ 120	$ 539	$ 126	$ 23	$ 7	$ 113	$ 10	$ 84	$ 94	$ 415	$ 94	$ 19	$ 4	$ 22			$ 7
Restructuring and other charges, after-tax and noncontrolling interests	54		170	328	175																							51	70	240	62	151	19	26	18	11	20				2	11	5	1	4	1																	44
Number of plants permanently shut down and demolished																																																																																											2	2	2	2	2
Restructuring and other charges, after-tax																																								3
Number of employees associated with layoff costs			470		530	190		190	55		115	180	115	180	30	10																																														75	245						30	45	90	45																30	15
Number of plants temporarily curtailed																																																																																															2	1
Reduction in production - result of market conditions, in metric tons per year			460,000	460,000																		84,000			190,000	200,000
Remaining smelting capacity subject to review				62,000
Additional smelting capacity subject to review				85,000
Reduction in combined capacity		200,000
Number of employees associated with layoff costs				1,830			470			1,230							90																																																						40
Accelerated depreciation	91			150														23	23
Other exit costs																																															10	49	133	49				44	55	44		5	38	5				40
Other asset impairment charges				91																			14	14
Inventory write-down - permanent shutdown and planned demolition of idled structures																																																			7	34	7
Inventory write-down, after-tax and non-controlling interests																																																			5	20	5
Additional charges related to shutdown actions				110
Number of facilities accelerated depreciation write off																											3
Number of non-U.S. locations permanently shutdown and demolished			2		2
Number of potlines to be shutdown and demolished																		2
Reduction in production - result of market conditions, in mt per year																		105,000
Reduction in production - result of market conditions, in mt per year																				280,000	44,000
Capacity of lines under review period			15 months
Total number of employees already laid off																																																																	745	745	1,350	1,350
Number of positions separated																																																																		2,075		1,660
Cash payments made against the layoff reserves																																																																	22	23	8	32
Minimum amount of cash payments expected to be paid beyond the end of the current annual period				40
Maximum amount of cash payments expected to be paid beyond the end of the current annual period				$ 45