Acquisition, Divestitures, Licensing Arrangements, Collaborative Arrangements and Privately Held Investment - AstraZeneca (Details) - USD ($)			3 Months Ended	12 Months Ended
		Dec. 22, 2016	Apr. 01, 2018	Dec. 31, 2017	Sep. 30, 2018
Business Acquisition [Line Items]
Goodwill	[1]			$ 55,952,000,000	$ 55,614,000,000
AstraZeneca [Member]
Business Acquisition [Line Items]
Payments for acquisitions, cash portion				$ 605,000,000
Milestone payment			$ 125,000,000
Deferred payment		$ 175,000,000
Maximum amount of potential milestone payments		75,000,000
Maximum amount of potential sales-related payments		$ 600,000,000
Term of royalty payments		10 years
Consideration transferred in business acquisition		$ 1,040,000,000
Identifiable intangible assets		894,000,000
Other current assets		92,000,000
Goodwill		73,000,000
Deferred tax liabilities		19,000,000
In Process Research and Development [Member] | AstraZeneca [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		166,000,000
Developed Technology Rights [Member] | AstraZeneca [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		728,000,000
Minimum [Member] | AstraZeneca [Member]
Business Acquisition [Line Items]
Undiscounted royalty payments		292,000,000
Maximum [Member] | AstraZeneca [Member]
Business Acquisition [Line Items]
Undiscounted royalty payments		$ 512,000,000

[1] Amounts may not add due to rounding.