Business Combinations and Divestitures - Purchase Price Allocation of Identifiable Intangible Assets (Details) - USD ($) $ in Millions		9 Months Ended
	Jun. 16, 2017	Sep. 30, 2018
Actelion
Business Acquisition [Line Items]
Total intangible assets	$ 25,010
Actelion | In-process research and development
Business Acquisition [Line Items]
Indefinite-lived Intangible Assets Acquired	780
Actelion | Patents and trademarks
Business Acquisition [Line Items]
Total amortizable intangibles	$ 24,230
Valchlor | Patents and trademarks
Business Acquisition [Line Items]
Total amortizable intangibles		$ 400