Restructuring and Related Implementation Charges - Summary of Restructuring and Related Costs (Details) - Global Growth and Efficiency Program - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Total Global Growth and Efficiency Program charges, pretax	$ 26	$ 58	$ 115	$ 246
Total Global Growth and Efficiency Program charges, aftertax	22	39	93	185
Cost of sales
Restructuring Cost and Reserve [Line Items]
Total Global Growth and Efficiency Program charges, pretax	8	16	19	51
Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Total Global Growth and Efficiency Program charges, pretax	9	22	24	60
Other (income) expense, net
Restructuring Cost and Reserve [Line Items]
Total Global Growth and Efficiency Program charges, pretax	8	9	64	122
Non-service related postretirement costs
Restructuring Cost and Reserve [Line Items]
Total Global Growth and Efficiency Program charges, pretax	$ 1	$ 11	$ 8	$ 13