Consolidated Statement of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Consolidated Statement of Operations [Abstract]
Revenues	$ 12,101.4	$ 11,571.0	$ 11,361.4	$ 11,094.5	$ 11,294.2	$ 11,251.8	$ 11,288.8	$ 11,138.4	$ 46,128.3	[1]	$ 44,973.2	[1]	$ 24,722.3	[1]
Cost of revenues	11,256.9	10,735.2	10,577.3	10,349.0	10,520.8	10,487.7	10,531.3	10,475.2	42,918.4	[1]	42,015.0	[1]	22,298.3	[1]
Gross profit	844.5	835.8	784.1	745.5	773.4	764.1	757.5	663.2	3,209.9		2,958.2		2,424.0
Selling, general and administrative	269.6	230.7	204.8	193.1	215.5	236.1	227.2	208.5	898.2		887.3		926.5
Operating income	574.9	605.1	579.3	552.4	557.9	528.0	530.3	454.7	2,311.7		2,070.9		1,497.5
Other (expense) income:
Interest income									12.4		4.9		5.3
Interest expense and other									(299.7)		(167.1)		(194.4)
Total other (expense) income									(287.3)		(162.2)		(189.1)
Income before income taxes									2,024.4		1,908.7		1,308.4
Provision for income taxes									748.6		704.1		481.8
Net income from continuing operations					329.6	307.1	307.3	260.6	1,275.8		1,204.6		826.6
Net (loss) income from discontinued operations, net of tax						(5.6)	(17.4)	(0.4)	0		(23.4)		1.0
Net income	$ 290.4	$ 324.7	$ 334.2	$ 326.5	$ 329.6	$ 301.5	$ 289.9	$ 260.2	$ 1,275.8		$ 1,181.2		$ 827.6
Weighted average number of common shares outstanding during the period:
Basic:									500.9		538.5		527.0
Diluted:									505.0		544.0		532.2
Basic earnings (loss) per share:
Continuing operations					$ 0.62	$ 0.58	$ 0.56	$ 0.47	$ 2.55		$ 2.24		$ 1.57
Discontinued operations						$ (0.01)	$ (0.03)				$ (0.04)
Net earnings	$ 0.60	$ 0.67	$ 0.66	$ 0.62	$ 0.62	$ 0.57	$ 0.53	$ 0.47	$ 2.55		$ 2.19		$ 1.57
Diluted earnings (loss) per share:
Continuing operations					$ 0.62	$ 0.57	$ 0.56	$ 0.47	$ 2.53		$ 2.21		$ 1.55
Discontinued operations						$ (0.01)	$ (0.03)				$ (0.04)
Net earnings	$ 0.59	$ 0.66	$ 0.66	$ 0.61	$ 0.62	$ 0.56	$ 0.53	$ 0.47	$ 2.53		$ 2.17		$ 1.56

[1] Includes retail pharmacy co-payments of $5786.6, $6,181.4, and $3,132.1, for the years ended December 31, 2011, 2010, and 2009, respectively.