Postretirement Benefits (Details 2) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined contribution plans
Costs related to defined contribution plans	$ 116	$ 99	$ 321	$ 286
U.S. Plans
Defined contribution plans
Costs related to defined contribution plans	97	83	267	235
Non-U.S. Plans
Defined contribution plans
Costs related to defined contribution plans	$ 19	$ 16	$ 54	$ 51