v3.20.2

Restructuring and Other Charges - Narrative (Details) $ in Millions		3 Months Ended				9 Months Ended		12 Months Ended
	Mar. 01, 2020 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2020 USD ($) employee	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($) employee	Sep. 30, 2020 USD ($) employee claimants	Sep. 30, 2019 USD ($) employee	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges (E)			$ 3		$ 64	$ 61	$ 104
Restructuring and other charges			$ 3		64	$ 61	104
Number of employees separated | employee			30			440
Cash payments, restructuring						$ 18				$ 15
Forecast
Restructuring Cost and Reserve [Line Items]
Cash payments, restructuring		$ 12						$ 1	$ 11
2020 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Expected number of employees separated | employee						580
Number of employees separated | employee						310
2019 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Expected number of employees separated | employee						370
Number of employees separated | employee						340
2019 Restructuring Program [Member] | Previously Reported [Member]
Restructuring Cost and Reserve [Line Items]
Expected number of employees separated | employee						480
Layoff costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			$ 1			$ 18
Cash payments, restructuring						16				12
Layoff costs | 2020 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Cash payments, restructuring			3			8
Layoff costs | 2019 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Cash payments, restructuring			2			8
Allocated costs, ParentCo
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			0		2	2	5
Other miscellaneous costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			1			7	2
Cash payments, restructuring						2				$ 3
Pension Settlement Cost [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			3			58
Reversal of Reserve [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges			$ 2			14
Environmental [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						5
Legacy Non-Income Taxes [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						4
Impairment of Carrying Value of Tradename [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges							10
Hard Alloy Extrusions Plant in South Korea | Disposed of by sale
Restructuring Cost and Reserve [Line Items]
Gain (loss) on sale	$ 31			$ 1
Aluminum Rolling Mill in Brazil
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges					$ 59		$ 59
Rolled Products and Building and Construction Systems
Restructuring Cost and Reserve [Line Items]
Number of employees separated | employee					120		370
Rolled Products and Building and Construction Systems | Layoff costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges					$ 3		$ 28
Building and Construction System and Extrustions [Member] | Layoff costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						$ 8
Number of employees separated | claimants						140
Building and Construction System and Extrustions [Member] | Other miscellaneous costs
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges						$ 11

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