Segment and Geographic Area Information - Schedule of Segment ATOI to Consolidated Net (Loss) Income Attributable to Arconic (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total segment ATOI									$ 1,087	$ 986	$ 983
Metal price lag									21	(115)	68
Interest expense									(499)	(473)	(442)
Impairment of goodwill										(25)
Discontinued operations									121	165	(329)
Net (Loss) Income Attributable to Arconic	$ (1,258)	$ 166	$ 135	$ 16	$ (701)	$ 44	$ 140	$ 195	(941)	(322)	268
Other [Member]
Segment Reporting Information [Line Items]
Impact of LIFO									(11)	66	(52)
Interest expense									(324)	(307)	(287)
Noncontrolling interests										(1)
Corporate expense									(306)	(252)	(268)
Impairment of goodwill										(25)
Restructuring and other charges									(114)	(192)	(249)
Discontinued operations									121	(165)	329
Other									$ (1,415)	$ (317)	$ (256)