Financial Instruments and Fair Value Measurements, Market risks, commodity prices and foreign currency rates (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Cash and Cash Equivalents, at Carrying Value [Abstract]
Amount of marketable securities classified as cash and cash equivalents	$ 1,191		$ 1,191		$ 389
Foreign currency [Abstract]
Foreign currency gain (loss)	$ 3	$ 2	$ (4)	$ 16