Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill gross, beginning balance		$ 5,198	$ 5,185
Impairment	(1,731)	(1,731)
Accumulated impairment losses, beginning balance		(28)	(28)
Goodwill, beginning balance		5,170	5,157
Acquisition of businesses			(1)
Translation		(24)	14
Goodwill gross, ending balance	5,174	5,174	5,198
Accumulated impairment losses, ending balance	(1,759)	(1,759)	(28)
Goodwill, ending balance	3,415	3,415	5,170
Alumina [Member]
Goodwill [Line Items]
Goodwill gross, beginning balance		10	11
Goodwill, beginning balance		10	11
Translation		(1)	(1)
Goodwill gross, ending balance	9	9	10
Goodwill, ending balance	9	9	10
Primary Metals [Member]
Goodwill [Line Items]
Goodwill gross, beginning balance		997	991
Impairment	(1,731)	(989)
Goodwill, beginning balance		997	991
Translation		(8)	6
Goodwill gross, ending balance	989	989	997
Accumulated impairment losses, ending balance	(989)	(989)
Goodwill, ending balance			997
Global Rolled Products [Member]
Goodwill [Line Items]
Goodwill gross, beginning balance		214	208
Goodwill, beginning balance		214	208
Translation		4	6
Goodwill gross, ending balance	218	218	214
Goodwill, ending balance	218	218	214
Engineered Products and Solutions [Member]
Goodwill [Line Items]
Goodwill gross, beginning balance		2,705	2,694
Accumulated impairment losses, beginning balance		(28)	(28)
Goodwill, beginning balance		2,677	2,666
Acquisition of businesses			(1)
Translation		(7)	12
Goodwill gross, ending balance	2,698	2,698	2,705
Accumulated impairment losses, ending balance	(28)	(28)	(28)
Goodwill, ending balance	2,670	2,670	2,677
Corporate [Member]
Goodwill [Line Items]
Goodwill gross, beginning balance		1,272	1,281
Impairment		(742)
Goodwill, beginning balance		1,272	1,281
Translation		(12)	(9)
Goodwill gross, ending balance	1,260	1,260	1,272
Accumulated impairment losses, ending balance	(742)	(742)
Goodwill, ending balance	$ 518	$ 518	$ 1,272