Segment and Geographic Area Information - Schedule of Reconciliation of Segment Reporting Information to Consolidated Net Income Attributable to Alcoa (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total segment ATOI									$ 1,217	$ 1,357	$ 1,885
Interest expense									(453)	(490)	(524)
Noncontrolling interests									41	(29)	194
Impairment of goodwill	(1,731)								(1,731)
Discontinued operations											(3)
Consolidated net (loss) income attributable to Alcoa	(2,339)	24	(119)	149	242	(143)	(2)	94	(2,285)	191	611
Unallocated Amounts (Net of Tax) [Member]
Segment Reporting Information [Line Items]
Impact of LIFO									52	20	(38)
Interest expense									(294)	(319)	(340)
Noncontrolling interests									(41)	29	(194)
Corporate expense									(284)	(282)	(290)
Impairment of goodwill									(1,731)
Restructuring and other charges									(607)	(142)	(196)
Discontinued operations											(3)
Other									$ (597)	$ (472)	$ (213)