Statement of Consolidated Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Sales	$ 1,283	$ 1,134	$ 3,687	$ 4,021
Cost of goods sold (exclusive of expenses below)	928	900	2,658	3,006
Selling, general administrative, and other expenses	70	66	190	219
Research and development expenses	4	5	13	13
Provision for depreciation and amortization	68	68	203	212
Restructuring and other charges	8	22	22	166
Operating income	205	73	601	405
Loss on debt redemption	118	0	141	64
Interest expense, net	63	77	201	241
Other expense, net	1	8	13	0
Income (loss) before income taxes	23	(12)	246	100
(Benefit) provision for income taxes	(4)	(48)	65	(5)
Income from continuing operations after income taxes	27	36	181	105
Income from discontinued operations after income taxes	0	0	0	50
Net income	27	36	181	155
Amounts Attributable to Howmet Aerospace Common Shareholders:
Net income	26	35	179	153
Net income	$ 26	$ 35	$ 179	$ 153
Earnings per share - basic
Continuing operations (in usd per share)	$ 0.06	$ 0.08	$ 0.42	$ 0.24
Discontinued operations (in usd per share)	0	0	0	0.11
Earnings per share - diluted
Continuing operations (in usd per share)	0.06	0.08	0.41	0.23
Discontinued operations (in usd per share)	$ 0	$ 0	$ 0	$ 0.11
Average Shares Outstanding:
Average shares outstanding - basic (in shares)	429	436	431	436
Average shares outstanding - diluted (in shares)	434	439	437	440