|**Accumulated Other Comprehensive Loss, Excluding Noncontrolling Interests (Tables)**         | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
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|**Equity [Abstract]**                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Schedule of Changes in Accumulated Other Comprehensive Loss, Net of Tax                       | The following table provides the changes, net of tax, inAccumulated other comprehensive loss:Net Unrealized Gains/(Losses)Benefit Plans(MILLIONS OF DOLLARS)Foreign Currency Translation AdjustmentsDerivative Financial InstrumentsAvailable-For-Sale SecuritiesActuarial Gains/(Losses)Prior Service (Costs)/Credits and OtherAccumulated Other Comprehensive Income/(Loss)Balance, December 31, 2019$(5,952)$20$(35)$(6,257)$584$(11,640)Other comprehensive income/(loss)(a)(1,020)(364)(32)(39)(35)(1,490)Balance, March 29, 2020$(6,973)$(344)$(67)$(6,296)$549$(13,131)(a)Includes after-tax losses of approximately$1.2 billionrelated to foreign currency translation adjustments attributable to our equity method investment in GSK Consumer Healthcare (seeNote 2B), partially offset by the results of our net investment hedging program.
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|The following table provides the changes, net of tax, inAccumulated other comprehensive loss:
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|(MILLIONS OF DOLLARS)                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Balance, December 31, 2019                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Other comprehensive income/(loss)(a)                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|Balance, March 29, 2020                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        

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