Preferred and Common Stock - Schedule of Unrecognized Compensation Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013
Equity [Abstract]
2014	$ 36
2015	18
2016	1
Totals	$ 55

Share based compensation, unrecognized compensation expense expected to be recognized in year three.

No definition available.

Name:	aa_ShareBasedCompensationUnrecognizedCompensationExpenseExpectedToBeRecognizedInYearThree
Namespace Prefix:	aa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration