Financial Instruments and Risk Management - General (Details) $ / shares in Units, € in Millions, shares in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($) approach $ / shares shares	Jul. 31, 2024 EUR (€)
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	$ 1,202
Net gain (loss) included in AOCI, after-tax	16
Net gain (loss) included in AOCI, after-tax, expected to be recognized in net earnings within the next 12 months	$ 16
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	$ 4,483
Net gain (loss) included in AOCI, after-tax	(3)
Net gain (loss) included in AOCI, after-tax, expected to be recognized in net earnings within the next 12 months	$ 9
Currency | Cash Flow Hedging
Financial Instruments and Risk Management
Longest duration of forecasted cash flow hedge transactions in years	2 years
Interest Rate
Financial Instruments and Risk Management
Notional amount of contracts	$ 600
Net gain (loss) included in AOCI, after-tax	12
Net gain (loss) included in AOCI, after-tax, expected to be recognized in net earnings within the next 12 months	$ 7
Interest Rate | Subsequent Event | First quarter of 2027
Financial Instruments and Risk Management
Notional amount of contracts | €		€ 250
Interest Rate | Subsequent Event | Second quarter of 2029
Financial Instruments and Risk Management
Notional amount of contracts | €		€ 600
Interest Rate | Cash Flow Hedging
Financial Instruments and Risk Management
Longest duration of forecasted cash flow hedge transactions in years	3 years
Equity contracts
Financial Instruments and Risk Management
Combined notional value (in shares) | shares	1.4
Change in company's stock price (in dollars per share) | $ / shares	$ 1