CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions		Total	Common Stock	[1]	Treasury Stock	[1]	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Equity Attributable to Noncontrolling Interests
Beginning balance at Dec. 31, 2015		$ 1,091	$ 5		$ (203)		$ 1,012	$ 876	$ (622)	$ 23
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)		819						821		(2)
Other comprehensive income		21							22	(1)
Share-based compensation awards	[2]	64			82		9	(27)
Treasury stock acquired	[3]	(300)			(300)
Employee benefit plan contribution from Pfizer Inc.	[4]	3					3
Noncontrolling Interest, Decrease from Deconsolidation	[5]	(6)							2	(8)
Dividends declared		(193)						(193)
Ending balance at Dec. 31, 2016		1,499	5		(421)		1,024	1,477	(598)	12
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)		862						864		(2)
Other comprehensive income		95							93	2
The fair value of our noncontrolling interest in a VIE	[6]	18								18
Purchases of shares from noncontrolling interest	[7]	(43)					(29)			(14)
Share-based compensation awards	[2]	68			69		15	(16)
Treasury stock acquired	[3]	(500)			(500)
Employee benefit plan contribution from Pfizer Inc.	[4]	3					3
Dividends declared		(216)						(216)
Ending balance at Dec. 31, 2017		1,786	5		(852)		1,013	2,109	(505)	16
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income/(loss)		1,424						1,428		(4)
Other comprehensive income		(124)							(124)	0
Adjustments to Additional Paid in Capital, Other	[6]	(14)
Share-based compensation awards	[2]	81			63		24	(6)
Treasury stock acquired	[3]	(698)			(698)
Employee benefit plan contribution from Pfizer Inc.	[4]	3					3
Noncontrolling Interest, Decrease from Deconsolidation	[6]									$ 12
Noncontrolling Interest, Period Increase (Decrease)	[6]	(26)
Dividends declared		(261)						(261)
Ending balance at Dec. 31, 2018		$ 2,185	$ 5		$ (1,487)		$ 1,026	$ 3,270	$ (629)

[1] As of December 31, 2018 and 2017, respectively, there were 479,562,326 and 486,130,461 outstanding shares of common stock and 22,328,917 and 15,760,782 shares or treasury stock. Treasury stock is recognized at the cost to reacquire the shares. For additional information, see Note 15. Stockholders' Equity.

[2] Includes the issuance of shares of Zoetis Inc. common stock and the reacquisition of shares of treasury stock associated with exercises of employee share-based awards. Also includes the reacquisition of shares of treasury stock associated with the vesting of employee share-based awards to satisfy tax withholding requirements. For additional information, see Note 14. Share-Based Payments and Note 15. Stockholders' Equity.

[3] Reflects the acquisition of treasury shares in connection with the share repurchase program. For additional information, see Note 15. Stockholders' Equity.

[4] Represents contributed capital from Pfizer Inc. associated with service credit continuation for certain Zoetis Inc. employees in Pfizer Inc.'s U.S. qualified defined benefit and U.S. retiree medical plans. See Note 13. Benefit Plans.

[5] Reflects the divestiture of our share of our Taiwan joint venture. See Note 5B. Acquisitions and Divestitures: Divestitures.

[6] For the twelve months ended December 31, 2018 and 2017, represents the acquisition and consolidation of a European livestock monitoring company.

[7] Represents the acquisition of the remaining 55 percent noncontrolling interest in Jilin Zoetis Guoyuan Animal Health Co., Ltd., a variable interest entity previously consolidated by Zoetis as the primary beneficiary.