Asset Impairment, Exit and Implementation Costs (Productivity Initiative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		18 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 29	$ 2	$ 56	$ 124
Payments for restructuring			41
Productivity Initiative [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 2		$ 124
Payments for restructuring			$ 28		$ 102