Financial Instruments and Risk Management - General (Details) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($) approach $ / shares shares
Commodity
Financial Instruments and Risk Management
Number of methods through which entity manages commodity price risk in connection with market price fluctuations of aluminum ingot | approach	2
Notional amount of contracts	$ 1,181
Net gain (loss) included in AOCI, after-tax	(23)
Net gain (loss) included in AOCI, after-tax, expected to be recognized in net earnings within the next 12 months	$ (23)
Commodity | Cash Flow Hedging
Financial Instruments and Risk Management
Longest duration of forecasted cash flow hedge transactions in years	1 year
Currency
Financial Instruments and Risk Management
Notional amount of contracts	$ 2,960
Currency | Cash Flow Hedging
Financial Instruments and Risk Management
Longest duration of forecasted cash flow hedge transactions in years	1 year
Interest Rate
Financial Instruments and Risk Management
Notional amount of contracts	$ 811
Net gain (loss) included in AOCI, after-tax	18
Net gain (loss) included in AOCI, after-tax, expected to be recognized in net earnings within the next 12 months	$ 18
Interest Rate | Cash Flow Hedging
Financial Instruments and Risk Management
Longest duration of forecasted cash flow hedge transactions in years	4 years
Equity contracts
Financial Instruments and Risk Management
Combined notional value (in shares) | shares	2.3
Change in company's stock price (in dollars per share) | $ / shares	$ 1