Hedging Activities and Fair Value Measurements (Details) £ in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2019 GBP (£) units	Mar. 31, 2019 USD ($) units	Dec. 31, 2018 GBP (£)	Dec. 31, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Document Period End Date	Mar. 31, 2019
Derivative, Notional Amount				$ 13,052		$ 12,326
Cost of Products Sold	$ 730	$ 672
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	56	(91)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	7	(12)
Interest Expense	109	61
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	(8)	0
Derivative Asset				436		304
Total Derivative Liabilities				48		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				9,750		7,239
Cash				114		133
Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value				335		237
Derivative Instruments in Hedges, Liabilities, at Fair Value				6		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	22	(23)
Foreign Currency Transaction Gain (Loss), before Tax	6	16
Net currency exchange gain (loss)	28	(8)
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
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				71
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				$ 41
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				$ 70		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				265		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				3		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				4,142		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	72	(118)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	(16)	27
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	56	(91)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(9)	15
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	2	(3)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(7)	$ 12
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Net Investment Hedging [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount				1,517		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	33
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, Tax	(7)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, after Tax	26
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), Reclassification, before Tax	(10)
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), after Reclassification, Tax	2
Gain (Loss) on Derivative Used in Net Investment Hedge, after Tax	$ 8
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount				7,393		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				101		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				42		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				436		304
Assets, Fair Value Disclosure				462		318
Liabilities, Fair Value Disclosure [Abstract]
Derivative Liability				48		80
Business Combination, Contingent Consideration, Liability				394		347
Financial and Nonfinancial Liabilities, Fair Value Disclosure				442		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				26		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				436		304
Assets, Fair Value Disclosure				436		304
Liabilities, Fair Value Disclosure [Abstract]
Derivative Liability				48		80
Business Combination, Contingent Consideration, Liability				0		0
Financial and Nonfinancial Liabilities, Fair Value Disclosure				48		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] | 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