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Cash Flow Information - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended	1 Months Ended	3 Months Ended
	Aug. 31, 2012	Dec. 31, 2014	Nov. 30, 2014	Mar. 31, 2014	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Common Stock [Line Items]
Principal amount of convertible notes		$ 8,798us-gaap_LongTermDebt			$ 1,250us-gaap_LongTermDebt	$ 8,262us-gaap_LongTermDebt
Number of shares, option exercised		18.1
Net of cash acquired		2,385
Loan for financing	250
Restricted cash	248					13	171
Firth Rixson [Member]
Schedule Of Common Stock [Line Items]
Net of cash acquired		2,995
Issuance of common stock		37	37
Common stock value		610
5.25% Convertible Notes Due 2014 [Member]
Schedule Of Common Stock [Line Items]
Principal amount of convertible notes		$ 575		$ 575
Convertible notes, interest rate		5.25%		5.25%
Convertible notes due date		Mar. 15, 2014		Mar. 15, 2014
Number of shares, option exercised		89.0		89.0