CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (UNAUDITED) - 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, 2017		$ 1,786	$ 5		$ (852)		$ 1,013	$ 2,109	$ (505)	$ 16
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		350						352		(2)
Other comprehensive income		77							76	1
Share-based compensation awards	[2]	12			37		(24)	(1)
Treasury stock acquired	[3]	(190)			(190)
Employee benefit plan contribution from Pfizer Inc.		1					1
Dividends declared		(61)						(61)
Ending balance at Mar. 31, 2018		1,975	5		(1,005)		990	2,399	(429)	15
Beginning balance at Dec. 31, 2018		2,185	5		(1,487)		1,026	3,270	(629)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		312						312		0
Other comprehensive income		31							31	0
Share-based compensation awards	[2]	17			44		(19)	(8)
Treasury stock acquired	[3]	(150)			(150)
Employee benefit plan contribution from Pfizer Inc.		1					1
Dividends declared		(79)						(79)
Ending balance at Mar. 31, 2019		$ 2,317	$ 5		$ (1,593)		$ 1,008	$ 3,495	$ (598)	$ 0

[1] As of March 31, 2019, and March 31, 2018, there were 479,026,001 and 484,724,245 outstanding shares of common stock, respectively, and 22,865,242 and 17,166,998 shares of treasury stock, respectively. Treasury stock is recognized at the cost to reacquire the shares. For additional information, see Note 14. Stockholders' Equity.

[2] Reflects the acquisition of treasury shares in connection with the share repurchase program. For additional information, see Note 14. Stockholders' Equity.

[3] 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.