Hedging Activities and Fair Value Measurements (Details) £ in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 GBP (£) units	Jun. 30, 2019 USD ($) units	Dec. 31, 2018 GBP (£)	Dec. 31, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount						$ 14,118		$ 12,326
Cost of Products Sold	$ 758	$ 739	$ 1,488	$ 1,411
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	2	151	58	59
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	11	(7)	18	(19)
Interest Expense	89	57	198	119
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	8	5	16	5
Derivative Asset						348		304
Total Derivative Liabilities						128		80
Assets, Fair Value Disclosure [Abstract]
Equity Securities, FV-NI						1		0
Liabilities, Fair Value Disclosure [Abstract]
Business Combination, Contingent Consideration, Liability						394		347
Debt Instrument, Fair Value Disclosure						10,421		7,239
Cash						97		133
Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value						318		237
Derivative Instruments in Hedges, Liabilities, at Fair Value						11		49
Not Designated as Hedging Instrument [Member] | Other Nonoperating Income (Expense) [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(152)	32	(130)	8
Foreign Currency Transaction Gain (Loss), before Tax	(4)	(33)	2	(17)
Net currency exchange gain (loss)	(156)	(1)	(127)	(9)
Interest Rate Contract [Member] | Cash Flow Hedging [Member] | Interest Expense [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 Rate Contract [Member] | Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Liabilities, at Fair Value						0		44
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount						0		1,000
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Expense [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0		0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	0		0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	0		0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	1		(2)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	0		0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	1		1
Foreign Exchange Contract [Member] | Cash Flow Hedging [Member] | Cost of Products Sold [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Foreign Currency Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months						70
Foreign Exchange Contract [Member] | Net Investment Hedging [Member] | Interest Expense [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						$ 48
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Forward Currency Contracts, Time to Maturity | units					60	60
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Prepaid And Other Current Assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value						$ 65		55
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Long-term Assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value						253		183
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Liabilities, at Fair Value						3		2
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Long-term Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Liabilities, at Fair Value						9		3
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount						4,269		3,962
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Cost of Products Sold [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	2	194	75	77
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	(1)	(44)	(17)	(17)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	2	151	58	59
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(16)	10	(25)	25
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	4	(2)	6	(6)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(12)	7	(19)	19
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Net Investment Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount						1,928		1,483
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Net Investment Hedging [Member] | Interest Expense [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	(5)	21	28	21
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, Tax	1	(5)	(6)	(5)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, after Tax	(4)	16	22	16
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), Reclassification, before Tax	(10)	(7)	(21)	(7)
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), after Reclassification, Tax	2	2	5	2
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	(8)	$ (5)	16	$ (5)
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount						7,921		5,880
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Prepaid And Other Current Assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value						30		67
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value						116		31
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Money Market Funds, at Carrying Value						25		13
Equity Securities, FV-NI						1		0
Derivative Asset						348		304
Assets, Fair Value Disclosure						374		318
Liabilities, Fair Value Disclosure [Abstract]
Derivative Liability						128		80
Business Combination, Contingent Consideration, Liability						394		347
Financial and Nonfinancial Liabilities, Fair Value Disclosure						522		427
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Money Market Funds, at Carrying Value						25		13
Equity Securities, FV-NI						1		0
Derivative Asset						0		0
Assets, Fair Value Disclosure						25		14
Liabilities, Fair Value Disclosure [Abstract]
Derivative Liability						0		0
Business Combination, Contingent Consideration, Liability						0		0
Financial and Nonfinancial Liabilities, Fair Value Disclosure						0		0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Money Market Funds, at Carrying Value						0		0
Equity Securities, FV-NI						0		0
Derivative Asset						348		304
Assets, Fair Value Disclosure						348		304
Liabilities, Fair Value Disclosure [Abstract]
Derivative Liability						128		80
Business Combination, Contingent Consideration, Liability						0		0
Financial and Nonfinancial Liabilities, Fair Value Disclosure						128		80
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Money Market Funds, at Carrying Value						0		0
Equity Securities, FV-NI						0		0
Derivative Asset						0		0
Assets, Fair Value Disclosure						0		0
Liabilities, Fair Value Disclosure [Abstract]
Derivative Liability						0		0
Business Combination, Contingent Consideration, Liability						394		347
Financial and Nonfinancial Liabilities, Fair Value Disclosure						$ 394		$ 347
Proposed BTG Acquisition [Member] | Not Designated as Hedging Instrument [Member] | Other Nonoperating Income (Expense) [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 151		$ 116
Proposed BTG Acquisition [Member] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount | £					£ 3,311		£ 2,000