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, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ 188	$ 80	$ 529	$ 358
Less: preferred stock dividends declared	1	1	2	2
Net income available to Howmet Aerospace common shareholders - basic	187	79	527	356
Net income available to Howmet Aerospace common shareholders - diluted	$ 187	$ 79	$ 527	$ 356
Average shares outstanding - basic (in shares)	412	415	412	417
Effect of dilutive securities:
Stock and performance awards (in shares)	3	5	5	5
Average shares outstanding - diluted (in shares)	415	420	417	422