Restructuring and Other Charges - Narrative (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018 USD ($) employee	Mar. 31, 2017 USD ($) employee	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 7	$ 73
Restructuring and other charges after tax and noncontrolling interest	$ 5	$ 69
Number of employees associated with layoff costs | employee	16	328
Cash payments made against the layoff reserves	$ 20		$ 65
Corporate
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | employee		42
Engineered Products and Solutions
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | employee		114
Global Rolled Products
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | employee		132
Transportation and Construction Solutions
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | employee		40
Pension Curtailment Charge
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	5
Restructuring and other charges after tax	4
Restructuring Programs Layoffs 2018
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	4
Restructuring and other charges after tax	$ 3
Number of employees associated with layoff costs | employee	16
Approximate number of employees already laid off | employee	8
Cash payments made against the layoff reserves	$ 1
Other Miscellaneous Items
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	2	$ (5)
Restructuring and other charges after tax	1	(3)
Other Adjustments
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	(4)	(1)
Restructuring and other charges after tax and noncontrolling interest	3	1
Other Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		19
Restructuring and other charges after tax		$ 13
Cash payments made against the layoff reserves	$ 0		$ 6
Restructuring Programs Layoffs 2017
Restructuring Cost and Reserve [Line Items]
Number of employees associated with layoff costs | employee	830	880
Approximate number of employees already laid off | employee	430
Cash payments made against the layoff reserves	$ 15
Restructuring Programs Layoffs 2016
Restructuring Cost and Reserve [Line Items]
Cash payments made against the layoff reserves	$ 4
Fusina Italy
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges		$ 60
Restructuring and other charges after tax		$ 60