Earnings Per Share and Common Stock - Reconciliation of Information Used to Compute Basic and Diluted EPS (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ 80	$ 27	$ 358	$ 181
Less: preferred stock dividends declared	1	1	2	2
Net income available to Howmet Aerospace common shareholders - basic	79	26	356	179
Net income available to Howmet Aerospace common shareholders - diluted	$ 79	$ 26	$ 356	$ 179
Average shares outstanding - basic (in shares)	415	429	417	431
Effect of dilutive securities:
Stock and performance awards (in shares)	5	4	5	5
Stock options (in shares)	0	1	0	1
Average shares outstanding - diluted (in shares)	420	434	422	437