Statement of Consolidated Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Sales	$ 1,195	$ 1,253	$ 2,404	$ 2,887
Cost of goods sold (exclusive of expenses below)	857	923	1,730	2,106
Selling, general administrative, and other expenses	55	74	120	153
Research and development expenses	4	4	9	8
Provision for depreciation and amortization	67	73	135	144
Restructuring and other charges	5	105	14	144
Operating income	207	74	396	332
Interest expense, net	89	144	161	228
Other expense (income), net	8	16	12	(8)
Income (loss) before income taxes	110	(86)	223	112
Provision (benefit) for income taxes	36	(2)	69	43
Income (loss) from continuing operations after income taxes	74	(84)	154	69
(Loss) income from discontinued operations after income taxes	0	(12)	0	50
Net income (loss)	74	(96)	154	119
Amounts Attributable to Howmet Aerospace Common Shareholders
Net income (loss)	73	(96)	153	118
Net income (loss)	$ 73	$ (96)	$ 153	$ 118
Earnings (loss) per share - basic
Continuing operations (in usd per share)	$ 0.17	$ (0.19)	$ 0.35	$ 0.16
Discontinued operations (in usd per share)	0	(0.03)	0	0.11
Earnings (loss) per share - diluted
Continuing operations (in usd per share)	0.17	(0.19)	0.35	0.15
Discontinued operations (in usd per share)	$ 0	$ (0.03)	$ 0	$ 0.11
Average Shares Outstanding
Average shares outstanding - basic (in shares)	432	436	433	436
Average shares outstanding - diluted (in shares)	437	436	438	440