Fair Value Measurements and Financial Instruments - Fair Value of Derivative Instruments and Other Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Designated derivative instruments
Derivative assets	$ 54	$ 29
Derivative liabilities	46	93
Other financial instruments
Total other financial instruments	100	37
Other assets | Interest rate swap contracts
Designated derivative instruments
Derivative assets	8	14
Other assets | Forward-starting interest rate swaps
Designated derivative instruments
Derivative assets	24	5
Other current assets
Other financial instruments
Marketable securities	100	37
Other current assets | Foreign currency contracts
Designated derivative instruments
Derivative assets	22	7
Other current assets | Commodity contracts
Designated derivative instruments
Derivative assets	0	3
Other liabilities | Interest rate swap contracts
Designated derivative instruments
Derivative liabilities	0	0
Other liabilities | Forward-starting interest rate swaps
Designated derivative instruments
Derivative liabilities	9	0
Other accruals | Foreign currency contracts
Designated derivative instruments
Derivative liabilities	37	93
Other accruals | Commodity contracts
Designated derivative instruments
Derivative liabilities	$ 0	$ 0