Reorganization of Business - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) employee	Apr. 01, 2017 USD ($)	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Reorganization of business charges	$ 13	$ 19
Restructuring charges	24
Adjustments	(11)
Restructuring reserve	48		$ 50
Amount Used	(15)
Employee separation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	22	15
Adjustments	(11)
Restructuring reserve	39		41
Amount Used	$ (13)
Restructuring charges in the period for total employee severance (in number of employees) | employee	300
Number of employees expected to be paid (in number of employees) | employee	400
Exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2
Adjustments	0
Restructuring reserve	9		$ 9
Amount Used	(2)
Other charges
Restructuring Cost and Reserve [Line Items]
Reorganization of business charges	8	15
Costs of sales
Restructuring Cost and Reserve [Line Items]
Reorganization of business charges	$ 5	$ 4