Contingencies and Commitments - Contingencies (Details) $ in Thousands, € in Millions			12 Months Ended
	Dec. 23, 2020 defendant	Jun. 06, 2019 USD ($) survivor	Dec. 31, 2021 USD ($) location	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Jun. 26, 2020 USD ($) entity	Sep. 30, 2018 USD ($)	Sep. 30, 2018 EUR (€)	Dec. 31, 2017 claim
Loss Contingencies [Line Items]
Number of cleanup locations (more than) | location			30
Remediation reserve balance			$ 15,000	$ 10,000
Remediation reserve balance, classified as a current liability			6,000	5,000
Payments related to remediation expenses applied against the reserve			$ 2,000	2,000
Total combined assessments				0			$ 64,000
Number of defendants | defendant	23
Number of plaintiffs | survivor		247
Monetary damages sought		$ 75
Number of claims | claim									2
Lehman Brothers International (Europe) (“LBIE”) Claims
Loss Contingencies [Line Items]
Number of entities | entity						2
Estimate of claim						$ 64,000
Spain
Loss Contingencies [Line Items]
Income taxes receivable				$ 53,000	€ 45
Tax agreement, indemnification of ultimate liability, percent				33.66%	33.66%
Alcoa Corporation
Loss Contingencies [Line Items]
Tax agreement, indemnification of ultimate liability, percent				49.00%	49.00%
Arconic Corporation
Loss Contingencies [Line Items]
Tax agreement, indemnification of ultimate liability, percent				33.66%	33.66%
Euro
Loss Contingencies [Line Items]
Total combined assessments | €								€ 54
Recurring Costs of Managing Hazardous Substances and Environmental Programs | Maximum
Loss Contingencies [Line Items]
Percentage of cost of goods sold			1.00%