Contingent Consideration (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration [Abstract]
Business Combination, Contingent Consideration, Liability Beginning Balance	$ 354
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	(108)	$ (28)
Payment of contingent consideration	(28)
Business Combination, Contingent Consideration, Liability Ending Balance	218
Business Combination, Contingent Consideration Arrangements [Abstract]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High			$ 658
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Business Combination, Contingent Consideration, Liability	218		218
Valuation Technique, Discounted Cash Flow [Member] | R&D, Regulatory and Commercialization-based Milestone [Member]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration [Abstract]
Business Combination, Contingent Consideration, Liability Ending Balance	96
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Business Combination, Contingent Consideration, Liability	96		96
Valuation Technique, Discounted Cash Flow [Member] | revenue-based payments [Member]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration [Abstract]
Business Combination, Contingent Consideration, Liability Ending Balance	121
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Business Combination, Contingent Consideration, Liability	$ 121		$ 121
Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member] | R&D, Regulatory and Commercialization-based Milestone [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Discount Rate, Fair Value Input	3.00%
Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member] | revenue-based payments [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Discount Rate, Fair Value Input	11.00%
Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member] | R&D, Regulatory and Commercialization-based Milestone [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Discount Rate, Fair Value Input	3.00%
Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member] | revenue-based payments [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Discount Rate, Fair Value Input	14.00%
Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member] | R&D, Regulatory and Commercialization-based Milestone [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
contingent consideration liability, probability of payment			90.00%
Discount Rate, Fair Value Input	3.00%
Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member] | revenue-based payments [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
contingent consideration liability, probability of payment			100.00%
Discount Rate, Fair Value Input	13.00%