Financial Instruments and Risk Management - General (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) approach $ / shares shares	Dec. 31, 2020 USD ($)
Financial Instruments and Risk Management
Aggregate fair value of derivative instruments with credit-risk-related contingent features that were in a net liability position	$ 3	$ 52
Collateral amount posted for derivative instruments with credit-risk-related contingent features that were in a net liability position	$ 0	$ 0
Commodity contracts
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 derivatives	$ 1,882
Gain (loss) on derivatives included in AOCI, net of tax	106
Net gain (loss) expected to be recognized in net earnings within the next 12 months	$ 104
Commodity contracts | Cash Flow Hedging
Financial Instruments and Risk Management
Period within which derivative will expire	2 years
Currency Exchange Rate Risk
Financial Instruments and Risk Management
Notional amount of derivatives	$ 2,761
Gain (loss) on derivatives included in AOCI, net of tax	17
Net gain (loss) expected to be recognized in net earnings within the next 12 months	$ 17
Currency Exchange Rate Risk | Cash Flow Hedging
Financial Instruments and Risk Management
Period within which derivative will expire	3 years
Interest rate swap and option contracts
Financial Instruments and Risk Management
Notional amount of derivatives	$ 1,182
Interest rate swap and option contracts | Cash Flow Hedging
Financial Instruments and Risk Management
Period within which derivative will expire	2 years
Equity contracts
Financial Instruments and Risk Management
Combined notional value (in shares) | shares	2,600,000
Change in company's stock price (in dollars per share) | $ / shares	$ 1