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
	Mar. 31, 2026	Mar. 31, 2025
Earnings Per Share [Abstract]
Net income	$ 580	$ 344
Less: preferred stock dividends declared	0	1
Net income available to Howmet Aerospace common shareholders - basic	580	343
Net income available to Howmet Aerospace common shareholders - diluted	$ 580	$ 343
Average shares outstanding - basic (in shares)	401	405
Effect of dilutive securities:
Stock and performance awards (in shares)	2	2
Average shares outstanding - diluted (in shares)	403	407