Acquisitions and Other Arrangements - Additional Information (Detail)			1 Months Ended	3 Months Ended		12 Months Ended
	Mar. 16, 2018 USD ($) Product	Jul. 27, 2017 USD ($)	Feb. 22, 2018 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)
Acquisitions And Collaborations [Line Items]
Total cash consideration, net of cash acquired				$ 219,000,000	$ 6,000,000
Claris Injectables Limited
Acquisitions And Collaborations [Line Items]
Percentage of ownership acquired		100.00%
Total cash consideration, net of cash acquired		$ 629,000,000
Amount allocated from total consideration to acquire intangible assets		280,000,000
Business acquisition settlement claims received			$ 73,000,000
Accrued liabilities released			$ 7,000,000
Claris Injectables Limited | Scenario Forecast
Acquisitions And Collaborations [Line Items]
Business acquisition benefit of settlement claims and accrued liabilities released						$ (80,000,000)
Claris Injectables Limited | IPR&D
Acquisitions And Collaborations [Line Items]
Amount allocated from total consideration to acquire in-process research and development with indefinite useful life		$ 140,000,000
Discount rate used to measure intangible assets		13.00%
Claris Injectables Limited | Developed Technology
Acquisitions And Collaborations [Line Items]
Amount allocated from total consideration to acquire intangible assets		$ 140,000,000
Acquired intangible assets, weighted-average useful life		8 years
Discount rate used to measure intangible assets		12.00%
Claris Injectables Limited | Marketing and Administrative Expenses
Acquisitions And Collaborations [Line Items]
Acquisition costs				7,000,000
Integration costs				7,000,000
Mallinckrodt plc | RECOTHROM and PREVELEAK
Acquisitions And Collaborations [Line Items]
Amount allocated from total consideration to acquire intangible assets	$ 108,000,000
Acquired intangible assets, weighted-average useful life	10 years
Number of products acquired | Product	2
Purchase price, upfront payment	$ 148,000,000
Maximum potential future payments	14,000,000
Maximum aggregate amount payable for the technology transfer	15,000,000
Maximum aggregate amount payable for royalties revenue net	$ 143,000,000
Mallinckrodt plc | RECOTHROM and PREVELEAK | Minimum
Acquisitions And Collaborations [Line Items]
Discount rate used to measure intangible assets	14.00%
Mallinckrodt plc | RECOTHROM and PREVELEAK | Maximum
Acquisitions And Collaborations [Line Items]
Discount rate used to measure intangible assets	15.00%
Celerity Pharmaceutical LLC | Bivalirudin
Acquisitions And Collaborations [Line Items]
Payment to acquire the rights				$ 37,000,000
Estimated economic life				12 years
Celerity Pharmaceutical LLC | Dexmedetomidine
Acquisitions And Collaborations [Line Items]
Payment to acquire the rights				$ 35,000,000
Estimated economic life				12 years