Commitments, Guarantees And Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2010
Purchase obligations in 2011	81.4
Purchase obligations in 2012	44.6
Purchase obligations in 2013	18.4
Purchase obligations in 2014	3.7
Medicare [Member]
Percentage of premiums and services revenues	65.00%
Medicaid And Other [Member]
Percentage of premiums and services revenues	2.00%
Military Services [Member]
Percentage of premiums and services revenues	11.00%
Military Services [Member] \| TRICARE South Region Contract [Member]
Original South Region contract, term in years	5

The aggregate amount of payments due in the fourth year after the balance sheet date to reduce a recorded unconditional purchase obligation.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 10

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25383-109308

Name:	us-gaap_RecordedUnconditionalPurchaseObligationDueInFourthYear
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant