Hedging Activities and Fair Value Measurements (Details) € in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($) units Rate	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	$ 33		$ 34
Derivative Instruments in Hedges, at Fair Value, Net	10,078				$ 10,218
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	92	$ 56
Cost of Goods and Services Sold	806	730
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	17	7
Other Operating Income (Expense), Net	36
Interest Expense	88	109
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	(5)	(8)
Derivative Asset, Fair Value, Gross Asset	509				321
Cash	353				165
Proceeds from secured borrowings relating to royalty arrangements			$ 256
Other Assets, Current	1,043				880
Other long-term assets	1,538				1,529
Derivative Liability, Fair Value, Gross Liability	1,025				1,037
Other Liabilities, Noncurrent	2,412				2,635
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	0				1
Debt Instrument, Fair Value Disclosure	11,008				11,020
Derivative Asset	292				216
Licensing arrangements, asset	298				332
Business Combination, Contingent Consideration, Liability	218				354
Licensing arrangements, liability	321				374
Net Investment Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Value of Outstanding Net Investment Hedges	1,954				1,950
Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value	404				288
Derivative Instruments in Hedges, Liabilities, at Fair Value	$ 982				1,009
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Forward Currency Contracts, Time to Maturity | units	60
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, at Fair Value, Net	$ 4,209				4,377
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, at Fair Value, Net	3,916				3,891
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, at Fair Value, Net	0
Net Investment Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, at Fair Value, Net	957				953
Net Investment Hedging [Member] | Designated as Hedging Instrument [Member] | foreign currency denominated in debt [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, at Fair Value, Net	997				997
Cost of Sales [Member] | Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months	116
Cost of Sales [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	119	72
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	(27)	(16)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	92	56
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(23)	(9)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	5	2
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(18)	(7)
Interest Expense [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	(5)
Interest Expense [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	1
Interest Expense [Member] | Net Investment Hedging [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Used in Net Investment Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	24
Interest Expense [Member] | Net Investment Hedging [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	22	33
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, Tax	(26)	(7)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, after Tax	(4)	26
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), Reclassification, before Tax	(6)	(10)
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), after Reclassification, Tax	1	2
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	5	8
Interest Expense [Member] | Net Investment Hedging [Member] | Designated as Hedging Instrument [Member] | foreign currency denominated in debt [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	24
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, Tax	(2)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, after Tax	22
Other Nonoperating Income (Expense) [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(15)	22
Foreign Currency Transaction Gain (Loss), before Tax	8	6
Net currency exchange gain (loss)	(7)	$ 28
Licensing arrangement assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Proceeds from Royalties Received	(47)
Increase (Decrease) in Fair Value Adjustments on Other Assets (Liabilities) Carried at Fair Value under Fair Value Option	$ 8
Weighted Average Discount Rate, Percent	15.00%
Licensing arrangement liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Increase (Decrease) in Fair Value Adjustments on Other Assets (Liabilities) Carried at Fair Value under Fair Value Option	$ 13
Payments for Royalties	$ (77)
Weighted Average Discount Rate, Percent	13.00%
Euro-denominated outstanding debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$ 903				1,004
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Licensing arrangements, asset	480
Licensing arrangements, liability	507
Prepaid Expenses and Other Current Assets [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value	112				72
Prepaid Expenses and Other Current Assets [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	106				33
Other Noncurrent Assets [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value	292				216
Other Current Liabilities [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Liabilities, at Fair Value	2				3
Other Current Liabilities [Member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	43				29
Other Noncurrent Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value	975				998
Other Noncurrent Liabilities [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Liabilities, at Fair Value	$ 4				8
Minimum [Member] | Licensing arrangement assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Discount Rate, Fair Value Input	11.00%
Minimum [Member] | Licensing arrangement liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Discount Rate, Fair Value Input	12.00%
Maximum [Member] | Licensing arrangement assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Discount Rate, Fair Value Input	15.00%
Maximum [Member] | Licensing arrangement liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Discount Rate, Fair Value Input	15.00%
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money Market Funds, at Carrying Value	$ 16				50
Equity Securities, FV-NI	0				1
Derivative Asset	509				321
Licensing arrangements, asset	480				518
Derivative Liability	1,025				1,037
Business Combination, Contingent Consideration, Liability	218				354
Licensing arrangements, liability	507				571
Financial and Nonfinancial Liabilities, Fair Value Disclosure	1,750				1,963
Assets, Fair Value Disclosure	1,006				890
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money Market Funds, at Carrying Value	16				50
Equity Securities, FV-NI	0				1
Derivative Asset	0				0
Licensing arrangements, asset	0				0
Derivative Liability	0				0
Business Combination, Contingent Consideration, Liability	0				0
Licensing arrangements, liability	0				0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0				0
Assets, Fair Value Disclosure	17				51
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money Market Funds, at Carrying Value	0				0
Equity Securities, FV-NI	0				0
Derivative Asset	509				321
Licensing arrangements, asset	0				0
Derivative Liability	1,025				1,037
Business Combination, Contingent Consideration, Liability	0				0
Licensing arrangements, liability	0				0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	1,025				1,037
Assets, Fair Value Disclosure	509				321
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money Market Funds, at Carrying Value	0				0
Equity Securities, FV-NI	0				0
Derivative Asset	0				0
Licensing arrangements, asset	480				518
Derivative Liability	0				0
Business Combination, Contingent Consideration, Liability	218				354
Licensing arrangements, liability	507				571
Financial and Nonfinancial Liabilities, Fair Value Disclosure	725				925
Assets, Fair Value Disclosure	480				518
November 2019 Aggregate Offering [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Long-term Debt				€ 900	1,000
December 2027 Notes [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Long-term Debt	$ 988				$ 1,011
Debt Instrument, Interest Rate, Stated Percentage	0.625%
R&D, Regulatory and Commercialization-based Milestone [Member] | Valuation Technique, Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	$ 96
R&D, Regulatory and Commercialization-based Milestone [Member] | Valuation Technique, Discounted Cash Flow [Member] | Weighted Average [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Discount Rate, Fair Value Input	3.00%
R&D, Regulatory and Commercialization-based Milestone [Member] | Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Discount Rate, Fair Value Input	3.00%
R&D, Regulatory and Commercialization-based Milestone [Member] | Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Discount Rate, Fair Value Input | Rate	3.00%