Reorganization of Business - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) employee	Jul. 01, 2017 USD ($)	Jun. 30, 2018 USD ($) employee	Jul. 01, 2017 USD ($)	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Reorganization of business charges	$ 25	$ 3	$ 38	$ 22
Restructuring charges			52
Adjustments	(3)		(14)
Restructuring reserve	52		52		$ 50
Payments for restructuring			36
Other charges
Restructuring Cost and Reserve [Line Items]
Reorganization of business charges	18	1	26	16
Costs of sales
Restructuring Cost and Reserve [Line Items]
Reorganization of business charges	7	2	12	6
Exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1		3	4
Adjustments			0
Restructuring reserve	9		9		9
Payments for restructuring			3
Employee separation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	27	8	49	23
Adjustments		$ (5)	(14)	$ (5)
Restructuring reserve	$ 43		43		$ 41
Payments for restructuring			$ 33
Restructuring charges in the period for total employee severance (in number of employees) | employee			600
Number of employees expected to be paid (in number of employees) | employee	600		600