Asset Impairment, Exit and Implementation Costs (Productivity Initiative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended	15 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 27	$ 122
Payments for restructuring	20
Facilities Consolidation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	27		$ 98	$ 71
Payments for restructuring	11		$ 16
Productivity Initiative [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 122
Payments for restructuring	$ 15				$ 89