Asset Impairment, Exit and Implementation Costs (Productivity Initiative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		21 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 15	$ 6	$ 71	$ 130
Payments for restructuring			54
Productivity Initiative [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 6		$ 130
Payments for restructuring			$ 31		$ 105