Inventories (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Inventory, Net [Abstract]
Inventory valuation reserves	$ 455		$ 455		$ 360
Finished goods	2,626		2,626		2,577
Work in process and raw material	2,055		2,055		1,930
Total inventories, net	4,681		4,681		$ 4,507
Inventory impairment	$ 12	$ 12	$ 88	$ 31