Condensed consolidating financial information (Details 1) (USD $) In Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Condensed Consolidating Statement of Operations
Revenues	$ 11,571.0	[1]	$ 11,251.8	[1]	$ 34,026.9	[1]	$ 33,679.0	[1]
Operating expenses	10,965.9		10,723.8		32,290.1		32,166.0
Operating income	605.1		528.0		1,736.8		1,513.0
Interest (expense) income, net	(88.4)		(40.0)		(176.5)		(122.6)
Income before income taxes	516.7		488.0		1,560.3		1,390.4
Provision for income taxes	192.0		180.9		574.9		515.4
Net income (loss) from continuing operations	324.7		307.1		985.4		875.0
Net loss from discontinued operations, net of tax	0		(5.6)		0		(23.4)
Net income (loss)	324.7		301.5		985.4		851.6
Express Scripts, Inc. [Member]
Condensed Consolidating Statement of Operations
Revenues	7,306.1		7,387.7		21,718.3		22,249.4
Operating expenses	6,907.0		7,027.3		20,452.8		21,129.9
Operating income	399.1		360.4		1,265.5		1,119.5
Interest (expense) income, net	(87.1)		(38.2)		(172.5)		(117.9)
Income before income taxes	312.0		322.2		1,093.0		1,001.6
Provision for income taxes	117.3		117.5		400.8		369.2
Net income (loss) from continuing operations	194.7		204.7		692.2		632.4
Equity in earnings of subsidiaries	130.0		96.8		293.2		219.2
Net income (loss)	324.7		301.5		985.4		851.6
Guarantors [Member]
Condensed Consolidating Statement of Operations
Revenues	4,218.3		3,840.8		12,199.7		11,363.6
Operating expenses	4,025.8		3,675.3		11,744.6		10,968.5
Operating income	192.5		165.5		455.1		395.1
Interest (expense) income, net	(1.4)		(1.8)		(4.4)		(4.8)
Income before income taxes	191.1		163.7		450.7		390.3
Provision for income taxes	74.2		62.0		170.2		145.1
Net income (loss) from continuing operations	116.9		101.7		280.5		245.2
Net income (loss)	116.9		101.7		280.5		245.2
Non-Guarantors [Member]
Condensed Consolidating Statement of Operations
Revenues	46.6		23.3		108.9		66.0
Operating expenses	33.1		21.2		92.7		67.6
Operating income	13.5		2.1		16.2		(1.6)
Interest (expense) income, net	0.1				0.4		0.1
Income before income taxes	13.6		2.1		16.6		(1.5)
Provision for income taxes	0.5		1.4		3.9		1.1
Net income (loss) from continuing operations	13.1		0.7		12.7		(2.6)
Net loss from discontinued operations, net of tax			(5.6)				(23.4)
Net income (loss)	13.1		(4.9)		12.7		(26.0)
Eliminations [Member]
Condensed Consolidating Statement of Operations
Equity in earnings of subsidiaries	(130.0)		(96.8)		(293.2)		(219.2)
Net income (loss)	$ (130.0)		$ (96.8)		$ (293.2)		$ (219.2)

[1] Includes retail pharmacy co-payments of $1,390.4 million and $1,478.5 million for the three months ended September 30, 2011 and 2010, respectively and $4,374.0 million and $4,688.4 million for the nine months ended September 30, 2011 and 2010, respectively.