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Acquisitions and Divestitures (Summary of Intangible Assts Acquired) (Details) - Pure Technologies Ltd - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jan. 31, 2018	Oct. 31, 2016
Business Acquisition [Line Items]
Intangible assets		$ 149	$ 149
Customer Relationships
Business Acquisition [Line Items]
Weighted-average useful life	18 years
Intangible assets			84
Technology
Business Acquisition [Line Items]
Intangible assets			38
Technology \| Minimum
Business Acquisition [Line Items]
Weighted-average useful life	3 years
Technology \| Maximum
Business Acquisition [Line Items]
Weighted-average useful life	10 years
Tradenames
Business Acquisition [Line Items]
Weighted-average useful life	17 years
Intangible assets			21
Internally Developed Software
Business Acquisition [Line Items]
Intangible assets			$ 6
Internally Developed Software \| Minimum
Business Acquisition [Line Items]
Weighted-average useful life	3 years