Commitments, Guarantees And Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Loss Contingencies [Line Items]
Purchase obligations in 2012	117
Purchase obligations in 2013	60
Purchase obligations in 2014	35
Purchase obligations in 2015	11
Purchase obligations thereafter	22
Medicare [Member]
Loss Contingencies [Line Items]
Percentage of premiums and services revenues	65.00%
Medicaid [Member]
Loss Contingencies [Line Items]
Percentage of premiums and services revenues	3.00%
Military Services [Member]
Loss Contingencies [Line Items]
Percentage of premiums and services revenues	10.00%
Military Services [Member] \| TRICARE South Region Contract [Member]
Loss Contingencies [Line Items]
Original South Region contract, term in years	5

Term of the Original South Region Contract

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- Definition

Percentage Of Total Premium And Services Revenues

+ References

No definition available.

+ Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid within one year of the balance sheet date.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 7

-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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid in more than three and within four years from the balance sheet date.

+ References

+ Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid in more than one and within two years from the balance sheet date.

+ References

+ Details

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid in more than two and within three years from the balance sheet date.

+ References

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- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid after five years from the balance sheet date.

+ References

No definition available.

+ Details

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