Segment Information - Schedule of Operating Results of Arconic's Reportable Segments (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total sales	$ 3,261	$ 3,234	$ 6,453	$ 6,289
Depreciation and amortization	129	124	255	250
Adjusted EBITDA	556	568	1,105	1,092
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total sales	3,290	3,277	6,507	6,368
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	37	29	71	58
Third-Party Sales [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Third-party sales	3,253	3,248	6,436	6,310
Engineered Products and Solutions [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	66	62	130	127
Adjusted EBITDA	310	329	616	634
Engineered Products and Solutions [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total sales	1,484	1,465	2,969	2,914
Engineered Products and Solutions [Member] | Third-Party Sales [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Third-party sales	1,484	1,465	2,969	2,914
Global Rolled Products [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	51	50	101	100
Adjusted EBITDA	164	163	335	318
Global Rolled Products [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total sales	1,305	1,345	2,588	2,558
Global Rolled Products [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	37	29	71	58
Global Rolled Products [Member] | Third-Party Sales [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Third-party sales	1,268	1,316	2,517	2,500
Transportation and Construction Solutions [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	12	12	24	23
Adjusted EBITDA	82	76	154	140
Transportation and Construction Solutions [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total sales	501	467	950	896
Transportation and Construction Solutions [Member] | Third-Party Sales [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Third-party sales	$ 501	$ 467	$ 950	$ 896