Business Combinations and Divestitures Divestitures (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 109
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 69
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	14 years	[1]
Patented Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 39
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	9 years	[1]
Tradenames [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 1
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	1 year	[1]

[1] (1) Determination of the weighted average period of the individual categories of intangible assets was based on the nature of applicable intangible asset and the expected future cash flows to be derived from the intangible asset. Amortization of intangible assets with definite lives is recognized over the period of time the assets are expected to contribute to future cash flows.