Restructuring and Other Charges - Additional Information (Detail)		3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2016 Employees	Sep. 30, 2016 USD ($) Employees	Sep. 30, 2015 USD ($) Employees T	Jun. 30, 2015 t	Sep. 30, 2016 USD ($) Employees	Sep. 30, 2015 USD ($) Employees t	Dec. 31, 2015 Employees
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		$ 18,000,000	$ 66,000,000		$ 134,000,000	$ 460,000,000
Restructuring and other charges after tax and noncontrolling interest		10,000,000	30,000,000		87,000,000	329,000,000
Inventory write down						4,000,000
Inventory write down after tax and noncontrolling interests						2,000,000
Minimum amount of cash payments expected to be paid beyond the end of the current annual period					30,000,000
Maximum amount of cash payments expected to be paid beyond the end of the current annual period					35,000,000
Restructuring Charges [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
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		6,000,000	$ 9,000,000		$ 3,000,000	38,000,000
Three Other Segments and Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees			15
Capacity closure | T			887,000,000,000
Pocos de Caldas Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Capacity closure | t				96,000
Point Henry Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Percentage of power supply					40.00%
Sao Luis Smelter [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						800
Curtailment capacity | t						74,000
Sao Luis Smelter [Member] | Primary Metals [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						680
Sao Luis Smelter [Member] | Alumina [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						120
Suriname [Member]
Restructuring Cost and Reserve [Line Items]
Curtailment capacity | t						1,330,000
Warrick Smelter, Wenatchee Smelter and Point Comfort [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		2,000,000			$ 84,000,000
Restructuring and other charges after tax and noncontrolling interest		1,000,000			56,000,000
Warrick, IN Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Other costs		2,000,000			38,000,000
Inventory write down					5,000,000
Inventory write down after tax and noncontrolling interests					3,000,000
Other related costs		2,000,000			4,000,000
Asset Retirement Obligation Costs [Member] | Warrick, IN Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Other costs		3,000,000			4,000,000
Exit Cost [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						$ 190,000,000
Restructuring and other charges after tax and noncontrolling interest						120,000,000
Divested Businesses [Member] | Rolling Mill in Russia [Member] | Global Rolled Products [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
Restructuring Programs Layoffs 2014 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			$ 33,000,000			62,000,000
Restructuring and other charges after tax and noncontrolling interest			$ 29,000,000			$ 50,000,000
Number of employees associated with layoff costs | Employees			370			970
Cash payments made against the layoff reserves		1,000,000			4,000,000
Restructuring Programs Layoffs 2014 [Member] | Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						50
Restructuring Programs Layoffs 2014 [Member] | Global Rolled Products [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						70
Restructuring Programs Layoffs 2014 [Member] | Primary Metals [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						165
Restructuring Programs Layoffs 2014 [Member] | Transportation and Construction Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees			355			410
Restructuring Programs Layoffs 2014 [Member] | Engineered Products and Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees						275
Other Miscellaneous Items [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		8,000,000	$ 2,000,000		16,000,000	$ 3,000,000
Restructuring and other charges after tax and noncontrolling interest		5,000,000	9,000,000		9,000,000	13,000,000
Other Adjustments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		8,000,000	4,000,000		20,000,000	12,000,000
Restructuring and other charges after tax and noncontrolling interest		4,000,000	2,000,000		13,000,000	9,000,000
Shutdown and Curtailment Actions [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges						$ 86,000,000
Number of employees associated with layoff costs | Employees						90
Shutdown and Curtailment Actions [Member] | Australia [Member]
Restructuring Cost and Reserve [Line Items]
Gain on sale of land			18,000,000
Gain on sale of land after tax			13,000,000
Layoff Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			11,000,000			$ 22,000,000
Other Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						82,000,000
Other Exit Costs [Member] | Three Other Segments and Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			11,000,000
Restructuring and other charges after tax and noncontrolling interest			$ 5,000,000
Asset Retirement Obligations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						45,000,000
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						29,000,000
Supplier and Customer Contract [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						8,000,000
Pension Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						$ 11,000,000
Restructuring And Related Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		20,000,000
Restructuring and other charges after tax and noncontrolling interest		$ 10,000,000
Restructuring Programs Layoffs 2015 [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges					54,000,000
Restructuring and other charges after tax and noncontrolling interest					$ 35,000,000
Number of employees associated with layoff costs | Employees	4,700	100			1,200		5,000
Approximate number of employees already laid off | Employees	4,100	4,100			4,100
Cash payments made against the layoff reserves		$ 17,000,000			$ 109,000,000
Restructuring Programs Layoffs 2015 [Member] | Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees		10			10
Restructuring Programs Layoffs 2015 [Member] | Global Rolled Products [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees					30
Restructuring Programs Layoffs 2015 [Member] | Primary Metals [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees		30			60
Restructuring Programs Layoffs 2015 [Member] | Transportation and Construction Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees					240
Restructuring Programs Layoffs 2015 [Member] | Engineered Products and Solutions [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees		60			860
Asset Impairment and Accelerated Depreciation [Member] | Warrick, IN Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges					$ 70,000,000
Severance costs		$ 4,000,000			24,000,000
Other costs		2,000,000			38,000,000
Contract Termination [Member] | Warrick, IN Smelter [Member]
Restructuring Cost and Reserve [Line Items]
Other costs		$ 3,000,000			$ 30,000,000
Restructuring Programs Layoffs 2016 [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | Employees	1,200
Approximate number of employees already laid off | Employees	900	900			900
Cash payments made against the layoff reserves		$ 8,000,000			$ 19,000,000