Condensed Consolidated Statement of Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Net Investment from Merck & Co., Inc. Merck and Co., Inc.	Accumulated Other Comprehensive (Loss) Income
Beginning balance at Dec. 31, 2019	$ 7,035				$ 7,949	$ (914)
Stockholders' Equity [Roll Forward]
Net income attributable to Organon & Co.	1,792				1,792
Other comprehensive loss, net of taxes	(78)					(78)
Net transfers to Merck & Co., Inc.	(1,414)				(1,414)
Ending balance at Sep. 30, 2020	7,335				8,327	(992)
Beginning balance at Jun. 30, 2020	7,005				8,041	(1,036)
Stockholders' Equity [Roll Forward]
Net income attributable to Organon & Co.	547				547
Other comprehensive loss, net of taxes	44					44
Net transfers to Merck & Co., Inc.	(261)				(261)
Ending balance at Sep. 30, 2020	7,335				8,327	(992)
Beginning balance at Dec. 31, 2020	5,486	$ 0	$ 0	$ 0	6,108	(622)
Beginning balance, shares at Dec. 31, 2020		0
Stockholders' Equity [Roll Forward]
Net income attributable to Organon & Co.	1,149			419	730
Other comprehensive loss, net of taxes	118					118
Net transfers to Merck & Co., Inc.	588
Net transfers from Merck & Co., Inc., including Separation Adjustments	680			81	588	11
Net consideration paid to Merck & Co. Inc. in connection with Separation	(9,000)				(9,000)
Cash dividends declared on common stock	(74)			(74)
Stock-based compensation plans and other (in shares)		29,051
Stock-based compensation plans and other	23			23
Issuance of common stock in connection with the Separation and reclassification of Net investment from Merck & Co., inc. (in shares)		253,516,000
Issuance of common stock in connection with the Separation and reclassification of Net investment from Merck & Co., inc.		$ 3		(1,577)	1,574
Ending balance at Sep. 30, 2021	(1,618)	$ 3	0	(1,128)	0	(493)
Ending balance, shares at Sep. 30, 2021		253,545,051
Beginning balance at Jun. 30, 2021	(1,934)	$ 3	0	(1,473)	0	(464)
Beginning balance, shares at Jun. 30, 2021		253,516,000
Stockholders' Equity [Roll Forward]
Net income attributable to Organon & Co.	323			323	0
Other comprehensive loss, net of taxes	(26)					(26)
Net transfers to Merck & Co., Inc.	0
Net transfers from Merck & Co., Inc., including Separation Adjustments	78			81		(3)
Cash dividends declared on common stock	(74)			(74)
Stock-based compensation plans and other (in shares)		29,051
Stock-based compensation plans and other	15			15
Ending balance at Sep. 30, 2021	$ (1,618)	$ 3	$ 0	$ (1,128)	$ 0	$ (493)
Ending balance, shares at Sep. 30, 2021		253,545,051