Business Combinations, Goodwill and Intangible Assets - Additional Information (Details) - USD ($)		3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Net sales from continuing operations				$ 2,622,000,000.0	$ 1,172,700,000	$ 1,514,100,000
Goodwill impairment		$ 25,200,000				25,200,000
Impairment associated with intangible assets				0	0	0
Amortization of definite-lived intangible assets				9,000,000.0	2,900,000	$ 2,800,000
Alcoa Warrick LLC [Member]
Finite Lived Intangible Assets [Line Items]
Business combination, purchase price	$ 670,000,000.0			670,000,000.0
Net sales from continuing operations			$ 1,141,200,000
Alcoa Warrick LLC [Member] | Selling, General, Administrative, Research and Development
Finite Lived Intangible Assets [Line Items]
Acquisition costs				$ 16,700,000	$ 5,500,000