Contingent Consideration (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 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	$ 6	$ 8	(102)	$ (9)
Payment of contingent consideration			(40)
Business Combination, Contingent Consideration, Liability Ending Balance	214		214
Business Combination, Contingent Consideration Arrangements [Abstract]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High					$ 627
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Business Combination, Contingent Consideration, Liability	214		214		214
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	100		100
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Business Combination, Contingent Consideration, Liability	100		100		100
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	114		114
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Business Combination, Contingent Consideration, Liability	$ 114		$ 114		$ 114
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]
contingent consideration liability, probability of payment					90.00%
Discount Rate, Fair Value Input					2.00%
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]
contingent consideration liability, probability of payment					53.00%
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]
contingent consideration liability, probability of payment					90.00%
Discount Rate, Fair Value Input					2.00%
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]
contingent consideration liability, probability of payment					100.00%
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					2.00%
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					87.00%
Discount Rate, Fair Value Input					13.00%