Earnings Per Share - Reconciliation of Information Used to Compute Basic and Diluted EPS (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	May 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]
(Loss) income from continuing operations attributable to Alcoa common shareholders		$ (2,285)	$ 191	$ 614
Less: preferred stock dividends declared		2	2	2
(Loss) income from continuing operations available to common equity		(2,287)	189	612
Less: dividends and undistributed earnings allocated to participating securities				1
(Loss) income from continuing operations available to Alcoa common shareholders-basic		(2,287)	189	611
Add: interest expense related to convertible notes	(1)			30
(Loss) income from continuing operations available to Alcoa common shareholders-diluted		$ (2,287)	$ 189	$ 641
Average shares outstanding-basic		1,070	1,067	1,061
Stock options			3	7
Stock and performance awards			6	4
Convertible notes				89
Average shares outstanding-diluted		1,070	1,076	1,161