Segment Information (Premium Revenue By Line Of Business) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Health plans services premiums	$ 2,632,069	$ 2,620,949
Commercial Premium Revenue [Member]
Segment Reporting Information [Line Items]
Health plans services premiums	1,325,400	1,453,200
Medicare Premium Revenue [Member]
Segment Reporting Information [Line Items]
Health plans services premiums	706,400	715,000
Medicaid Premium Revenue [Member]
Segment Reporting Information [Line Items]
Health plans services premiums	$ 600,300	$ 452,700

Amount of insurance premium revenue recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(e))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-HCO

-Paragraph 10

-IssueDate 2006-05-01

-Chapter 8

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_HealthCareOrganizationPremiumRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration