Other income (expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Income and Expenses [Abstract]
Investment and interest income	$ 52	$ 36
Foreign exchange gains (losses)	18	(19)
Royalty Income, Nonoperating	25	31
Net periodic pension and OPEB income (cost), excluding service cost	26	86
Gain (Loss) on securities	39	(2)
Miscellaneous income (loss)	0	(5)
Other income (expense)	$ 160	$ 127