Financial Instruments - Fair Value of Derivative Instruments (Details) € in Millions, kr in Millions, SFr in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2020 DKK (kr)	Mar. 31, 2020 EUR (€)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 CHF (SFr)	Dec. 31, 2019 DKK (kr)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CHF (SFr)
Derivatives, Fair Value [Line Items]
Unrecognized net gains/(losses) on cross-currency interest rate swap contracts, recorded, net of tax	$ 17	$ 8
Other noncurrent liabilities					$ 251				$ 229
Other current liabilities					50				55
Other noncurrent assets					105				98
Total derivatives					34				25
Collateral received					28
Foreign currency forward-exchange contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Foreign currency forward-exchange contracts	6	(4)
Derivative notional amount					1,272				1,364
Total derivatives					14				2
Foreign currency forward-exchange contracts | Derivatives Not Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Derivative assets					19				7
Foreign currency forward-exchange contracts | Derivatives Not Designated as Hedging Instruments | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities					(5)				(5)
Cross-currency interest rate swap contracts
Derivatives, Fair Value [Line Items]
Derivative notional amount			kr 600	€ 650	150	SFr 25	kr 600	€ 650	150	SFr 25
Cross-currency interest rate swap contracts | Derivatives Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Unrecognized net gains/(losses) on cross-currency interest rate swap contracts, recorded, net of tax	17	18
Gain (Loss) on Components Excluded from Assessment of Interest Rate Fair Value Hedge Effectiveness	6	4
Total derivatives					20				23
Cross-currency interest rate swap contracts | Derivatives Designated as Hedging Instruments: | Other current assets
Derivatives, Fair Value [Line Items]
Total derivatives					7				4
Cross-currency interest rate swap contracts | Derivatives Designated as Hedging Instruments: | Other current liabilities
Derivatives, Fair Value [Line Items]
Total derivatives					(3)				(3)
Cross-currency interest rate swap contracts | Derivatives Designated as Hedging Instruments: | Other noncurrent assets
Derivatives, Fair Value [Line Items]
Total derivatives					36				20
zts_FixedtoFloatInterestRateSwap | Derivatives Designated as Hedging Instruments: | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative assets					12				(2)
zts_ForwardStartingInterestRateSwap | Derivatives Designated as Hedging Instruments:
Derivatives, Fair Value [Line Items]
Unrecognized net gains/(losses) on cross-currency interest rate swap contracts, recorded, net of tax	$ (27)	$ 0
zts_ForwardStartingInterestRateSwap | Derivatives Designated as Hedging Instruments: | Other noncurrent assets
Derivatives, Fair Value [Line Items]
Derivative assets					0				5
zts_ForwardStartingInterestRateSwap | Derivatives Designated as Hedging Instruments: | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative assets					$ (32)				$ (1)