Financial Instruments - Fair Value of Derivative Instruments (Details) € in Millions, kr in Millions, SFr in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 EUR (€)	Jun. 30, 2020 CHF (SFr)	Jun. 30, 2020 DKK (kr)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 CHF (SFr)	Dec. 31, 2019 DKK (kr)
Derivatives, Fair Value [Line Items]
Unrecognized net gains/(losses) on cross-currency interest rate swap contracts, recorded, net of tax			$ 3	$ 4
Other noncurrent liabilities	$ 271		271					$ 229
Other current liabilities	65		65					55
Other noncurrent assets	92		92					98
Total derivatives	9		9					25
Collateral received	25		25
Cash flow hedges gain expected to be reclassified from AOCI into earnings over the next 12 months			1
Foreign currency forward-exchange contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Foreign currency forward-exchange contracts	4	$ 8	10	4
Derivative notional amount	1,550		1,550					1,364
Total derivatives	(1)		(1)					2
Foreign currency forward-exchange contracts | Derivatives Not Designated as Hedging Instruments | Other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	18		18					7
Foreign currency forward-exchange contracts | Derivatives Not Designated as Hedging Instruments | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	(19)		(19)					(5)
Cross-currency interest rate swap contracts
Derivatives, Fair Value [Line Items]
Derivative notional amount	150		150		€ 650	SFr 25	kr 600	150	€ 650	SFr 25	kr 600
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	(14)	(4)	3	14
Gain (Loss) on Components Excluded from Assessment of Interest Rate Fair Value Hedge Effectiveness	4	4	10	8
Total derivatives	10		10					23
Cross-currency interest rate swap contracts | Derivatives Designated as Hedging Instruments: | Other current assets
Derivatives, Fair Value [Line Items]
Total derivatives	9		9					4
Cross-currency interest rate swap contracts | Derivatives Designated as Hedging Instruments: | Other current liabilities
Derivatives, Fair Value [Line Items]
Total derivatives	(5)		(5)					(3)
Cross-currency interest rate swap contracts | Derivatives Designated as Hedging Instruments: | Other noncurrent assets
Derivatives, Fair Value [Line Items]
Total derivatives	24		24					20
zts_FixedtoFloatInterestRateSwap | Derivatives Designated as Hedging Instruments: | Other noncurrent assets
Derivatives, Fair Value [Line Items]
Derivative assets	14		14					0
zts_FixedtoFloatInterestRateSwap | Derivatives Designated as Hedging Instruments: | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative assets	0		0					(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	0	$ 0	(27)	$ 0
zts_ForwardStartingInterestRateSwap | Derivatives Designated as Hedging Instruments: | Other noncurrent assets
Derivatives, Fair Value [Line Items]
Derivative assets	0		0					5
zts_ForwardStartingInterestRateSwap | Derivatives Designated as Hedging Instruments: | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative assets	$ (32)		$ (32)					$ (1)