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, 2025	Mar. 31, 2024
Earnings Per Share [Abstract]
Net income	$ 344	$ 243
Less: preferred stock dividends declared	1	1
Net income available to Howmet Aerospace common shareholders - basic	343	242
Net income available to Howmet Aerospace common shareholders - diluted	$ 343	$ 242
Average shares outstanding - basic (in shares)	405	410
Effect of dilutive securities:
Stock and performance awards (in shares)	2	2
Average shares outstanding - diluted (in shares)	407	412