Accounting Policies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Sales	$ 3,841	$ 3,686	$ 7,671	$ 7,385
Cost of Goods Sold	(2,949)	(2,785)	(5,925)	(5,545)
Net income	(164)	(154)	(244)	(323)
Selling, general and administrative expense	(588)	(579)	(1,179)	(1,155)
Other (income) expense	45	16	82	24
Cumulative effect of adoption of new accounting standards						$ (1)	$ 0
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net Sales	8		7
Net income	(6)		(5)
Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Goods Sold		7		12
Selling, general and administrative expense		4		7
General and administrative expense		$ 3		$ 6
Other (income) expense			9
Accounting Standards Update 2016-09 | Scenario, Forecast
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net periodic defined benefits expense (reversal of expense)					$ 35
Net periodic defined benefits expense (reversal of expense), corporate related costs					5
Net periodic defined benefits expense (reversal of expense), excluding service cost component					90
Net periodic defined benefits expense (reversal of expense), excluding service cost component, corporate related costs					$ 15
Accounting Standards Update 2016-16 | Deferred Income Taxes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption of new accounting standards	7		7
Accounting Standards Update 2016-16 | Other assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption of new accounting standards	(5)		(5)
Accounting Standards Update 2016-16 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption of new accounting standards	$ 2		$ 2