Cash Flow Information - Additional Information (Detail) $ / shares in Units, $ in Millions								1 Months Ended					12 Months Ended			14 Months Ended	23 Months Ended	31 Months Ended
	Oct. 05, 2016 $ / shares shares	Aug. 31, 2016 USD ($)	Jul. 31, 2015 USD ($) shares	Jul. 23, 2015 shares	Jul. 22, 2015 shares	Jun. 16, 2014 shares	Jun. 15, 2014 shares	Aug. 31, 2016 USD ($)	Aug. 30, 2016 USD ($)	Jul. 30, 2015 shares	Nov. 30, 2014 shares	Nov. 29, 2014 shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Oct. 04, 2016 $ / shares shares	Oct. 04, 2016 $ / shares shares	Oct. 04, 2016 $ / shares shares	Mar. 31, 2014	Dec. 31, 2013 shares
Schedule Of Common Stock [Line Items]
Reverse stock split ratio	0.33												0.33
Common stock share outstanding | shares	400,000,000												438,519,780	1,310,160,141	1,216,663,661	1,300,000,000	1,300,000,000	1,300,000,000		1,071,011,162
Common stock par value | $ / shares	$ 1.00															$ 1.00	$ 1.00	$ 1.00
Decrease in common stock due to reverse stock split													$ (877)
Increase in additional paid in capital due to reverse stock split													877
Retirement of treasury stock		$ 25						$ 76	$ 76
Common stock conversion transaction value														$ 870	$ 610
Principal amount of convertible notes													$ 8,048	8,789
Number of shares, option exercised | shares													8,900,000
Business acquisition purchase price													$ (10)	$ (97)	2,385
Common Stock [Member]
Schedule Of Common Stock [Line Items]
Retirement of treasury stock								76	76				76
Additional Capital [Member]
Schedule Of Common Stock [Line Items]
Retirement of treasury stock								$ 2,563	$ 2,563				$ 2,563
Firth Rixson [Member]
Schedule Of Common Stock [Line Items]
Common stock shares issued for conversion transaction | shares						36,523,010	12,174,337
Business acquisition purchase price															2,995
Issuance of common stock | shares	12,000,000																37,000,000
Common stock value															610
RTI [Member]
Schedule Of Common Stock [Line Items]
Common stock conversion transaction value			$ 870
Common stock shares issued for conversion transaction | shares	29,000,000		29,000,000	87,397,414	29,132,471					87,000,000						87,000,000
5.25% Convertible Notes Due 2014 [Member]
Schedule Of Common Stock [Line Items]
Principal amount of convertible notes															$ 575
Convertible notes, interest rate															5.25%				5.25%
Convertible notes due date															Mar. 15, 2014
Number of shares, option exercised | shares															30,000,000			89,000,000
5.25% Convertible Notes Due 2014 [Member] | Firth Rixson [Member]
Schedule Of Common Stock [Line Items]
Issuance of common stock | shares											12,000,000	37,000,000