Statement of Consolidated Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Sales (D)	$ 5,259	$ 7,098	$ 6,778
Cost of goods sold (exclusive of expenses below)	3,878	5,214	5,114
Selling, general administrative, and other expenses	277	400	371
Research and development expenses	17	28	41
Provision for depreciation and amortization	279	295	314
Restructuring and other charges (E)	182	582	163
Operating income	626	579	775
Interest expense (F)	381	338	377
Other expense (income), net (G)	74	31	(30)
Income before income taxes	171	210	428
(Benefit) provision for income taxes (I)	(40)	84	119
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent, Total	211	126	309
Income from discontinued operations after income taxes (C)	50	344	333
Net income	261	470	642
Amounts Attributable to Howmet Aerospace Common Shareholders (K):
Net income	$ 259	$ 477	$ 651
Earnings per share - basic
Continuing operations (in usd per share)	$ 0.48	$ 0.28	$ 0.64
Discontinued operations (in usd per share)	0.11	0.77	0.69
Earnings per share - diluted
Continuing operations (in usd per share)	0.48	0.27	0.63
Discontinued operations (in usd per share)	$ 0.11	$ 0.76	$ 0.67
Average Shares Outstanding (J):
Average shares outstanding - basic (in shares)	435	446	483
Average shares outstanding - diluted (in shares)	439	463	503