Goodwill And Other Intangible Assets (Summary Of The Change In The Carrying Amount Of Goodwill By Reportable Segment) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended																	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Amerigroup [Member]	Dec. 31, 2012 1 800 Contacts [Member]	Dec. 31, 2011 CareMore [Member]	Dec. 31, 2012 Commercial [Member]	Dec. 31, 2011 Commercial [Member]	Dec. 31, 2012 Commercial [Member] Amerigroup [Member]	Dec. 31, 2012 Commercial [Member] 1 800 Contacts [Member]	Dec. 31, 2011 Commercial [Member] CareMore [Member]	Dec. 31, 2012 Consumer [Member]	Dec. 31, 2011 Consumer [Member]	Dec. 31, 2012 Consumer [Member] Amerigroup [Member]	Dec. 31, 2012 Consumer [Member] 1 800 Contacts [Member]	Dec. 31, 2011 Consumer [Member] CareMore [Member]	Dec. 31, 2012 Other And Eliminations [Member]	Dec. 31, 2010 Other And Eliminations [Member]	Dec. 31, 2012 Other And Eliminations [Member] Amerigroup [Member]	Dec. 31, 2012 Other And Eliminations [Member] 1 800 Contacts [Member]	Dec. 31, 2011 Other And Eliminations [Member] CareMore [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 13,858.7	$ 13,264.9				$ 9,943.6	$ 9,944.8				$ 3,915.1	$ 3,320.1				$ 0	$ 0
Goodwill acquired			3,033.1	620.7	595.3			0	620.7	0			3,033.1	0	595.3			0	0	0
Measurement period adjustments	(2.0)	(1.5)				(0.3)	(1.2)				(1.7)	(0.3)				0
Goodwill, Ending Balance	17,510.5	13,858.7				10,564.0	9,943.6				6,946.5	3,915.1				0	0
Accumulated impairment as of December 31, 2012	$ (41.0)					$ (41.0)					$ 0					$ 0