Income Taxes - Reconciliation of U.S. Federal Statutory Rate to Arconic's Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	21.00%	21.00%	21.00%
Foreign tax rate differential	0.10%	(0.70%)	(1.20%)
U.S. and residual tax on foreign earnings	1.20%	6.50%	5.60%
U.S. state and local taxes	0.70%	1.00%	2.20%
Federal cost of state tax	(0.20%)	(0.30%)	(2.00%)
Permanent differences related to asset disposals and items included in restructuring and other charges	0.00%	(0.30%)	6.80%
Non-deductible officer compensation	1.20%	1.60%	3.50%
Statutory tax rate and law changes	0.10%	1.00%	(15.90%)
Tax holidays	(0.50%)	(0.40%)	(0.40%)
Tax credits	(0.90%)	(10.40%)	(0.40%)
Changes in valuation allowances	1.40%	5.10%	74.80%
Changes in uncertain tax positions	0.00%	0.00%	(116.90%)
Excess benefit for stock compensation	(0.80%)	(0.30%)	(0.70%)
Prior year tax adjustments	(0.10%)	(3.70%)	(1.70%)
Other	(0.60%)	0.30%	1.90%
Effective tax rate	22.60%	20.40%	(23.40%)
Tax law change expense (benefit)			$ (30)
Benefit for income tax credits related to development incentives in Hungary		$ 32
Favorable spanish tax case decision			104
Reserve liability			64
Tax position expense (benefit)			$ (30)