Commitments and Contingencies (Details) (USD $)	1 Months Ended		6 Months Ended
	Feb. 28, 2011 item	Oct. 31, 2003 item	Jun. 30, 2012 item
Commitments and Contingencies
Number of store leases guaranteed			76
Number of adjudication platforms under investigation			2
Loss contingencies
Number of additional subpoenas received	2
Number of pharmacies filing putative action		2
Number of competitors against whom putative actions are filed		2
Number of Caremark entities named as defendants		2
Number of states participating in multi-state investigation			28
Lauriello Lawsuit
Loss contingencies
Lauriello lawsuit, amount sought in compensatory damages plus other non-specified damages			3,200,000,000
Multi-state investigation under FTC
Loss contingencies
Amount required to be paid in consumer redress, to be distributed to impacted RxAmerica Medicare Part D beneficiaries			5,000,000