Commitments and Contingencies (Details)				1 Months Ended									3 Months Ended	9 Months Ended
	Oct. 11, 2016	Dec. 22, 2014 qui_tam_complaint	Oct. 29, 2010 employee	Oct. 31, 2016 USD ($) state	Aug. 31, 2016 USD ($)	Jul. 31, 2016 USD ($)	Feb. 29, 2016 plaintiff	Sep. 30, 2015 pharmacy	Mar. 31, 2010 state	Dec. 31, 2009 USD ($)	Feb. 28, 2006 class_action_complaint officer director	Oct. 31, 2003 class_action_complaint competitor defendant pharmacy	Sep. 30, 2015 class_action_complaint	Sep. 30, 2016 USD ($) store_lease
Loss contingencies
Number of store leases guaranteed | store_lease														87
Year the last lease expires														2047
Number of competitors against whom putative actions are filed | class_action_complaint												3	2
Number of Caremark entities named as defendants | defendant												2
Number of states participating in multi-state investigation | state									28
Cases consolidated, number | class_action_complaint													2
Litigation settlement, expense						$ 3,500,000
Subsequent Event
Loss contingencies
Corporate integrity agreement term (in years)	5 years
Number of states in which plaintiffs reside | state				11
Omnicare, Inc.
Loss contingencies
Number of competitors against whom putative actions are filed		2									2
Number of officers named in lawsuit | officer											3
Number of directors named in lawsuit | director											2
Number of pharmacies indicated in subpoena | pharmacy								8
Lauriello Lawsuit
Loss contingencies
Settlement agreement in principle medoff securities class action lawsuit														$ 80,000,000
North Jackson Pharmacy, Inc. and C&C, Inc. d/b/a Big C Discount Drugs, Inc. vs Caremark
Loss contingencies
Number of pharmacies filing putative action | pharmacy												2
Number of competitors against whom putative actions are filed | class_action_complaint												1
Number of Caremark entities named as defendants | defendant												3
Number of competitors against whom putative actions are filed | competitor												2
Wuotila Derivative Matter
Loss contingencies
Settlement agreement in principle medoff securities class action lawsuit										$ 270,000
Banigan and Templin v. Organon USA, Inc., Omnicare, Inc. and PharMerica Corporation
Loss contingencies
Settlement agreement in principle medoff securities class action lawsuit					$ 23,000,000
Number of former employees | employee			2
Darlene Ervin v. Omnicare, Inc. | Subsequent Event
Loss contingencies
Settlement agreement in principle medoff securities class action lawsuit				$ 2,200,000.0
Pure Service Pharmacy Acquisition [Member]
Loss contingencies
Settlement agreement in principle medoff securities class action lawsuit														1,500,000.0
Omnicare Auto Label Verification System [Member]
Loss contingencies
Settlement agreement in principle medoff securities class action lawsuit														$ 8,000,000
Spetter v. Abbott Laboratories, Inc., Omnicare, Inc., and PharMerica Corp. | Omnicare, Inc. | Subsequent Event
Loss contingencies
Settlement agreement in principle medoff securities class action lawsuit				$ 28,100,000
Sheet Metal Workers Local No. 20 Welfare and Benefit Fund v. CVS Health Corp.
Loss contingencies
Number of pharmacies filing putative action | plaintiff							2