| **Goodwill and Other Intangible Assets (Tables)**                    | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
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| **Goodwill and Intangible Assets Disclosure [Abstract]**             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| Schedule of Changes in the Carrying Amount of Goodwill               | The following table shows changes in the carrying amount of Goodwill for the years ended December 31, 2012, 2011, and 2010 (in millions):  AmountGoodwill as of December 31, 2009$407.7Acquisitions12.6Goodwill as of December 31, 2010420.3Acquisition1.4Goodwill as of December 31, 2011421.7Consolidation of joint venture formerly accounted for under the equity method of accounting15.6Goodwill as of December 31, 2012$437.3                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Schedule of Intangible Assets by Major Class                         | The following table provides information regarding our other intangible assets (in millions):  Gross Carrying Amount Accumulated Amortization NetCertificates of need:     2012$9.9 $(2.5) $7.420117.0 (2.3) 4.7Licenses:     2012$50.6 $(42.9) $7.7201150.2 (41.7) 8.5Noncompete agreements:     2012$34.3 $(20.3) $14.0201133.0 (17.1) 15.9Tradenames:     2012$16.1 $(8.6) $7.5201115.0 (8.0) 7.0Internal-use software:     2012$84.7 $(55.0) $29.7201164.8 (51.1) 13.7Market access assets:     2012$13.2 $(6.3) $6.9201113.2 (5.3) 7.9Total intangible assets:     2012$208.8 $(135.6) $73.22011183.2 (125.5) 57.7 |
| Schedule of Amortization Expense, Intangible Assets                  | Amortization expense for other intangible assets is as follows (in millions):  For the Year Ended December 31, 2012 2011 2010Amortization expense$13.4 $15.2 $12.9                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| Schedule of Future Estimated Amortization Expense, Intangible Assets | Total estimated amortization expense for our other intangible assets for the next five years is as follows (in millions): Year Ending December 31,Estimated Amortization Expense2013$12.1201410.020158.620166.820174.2                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |

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| - Definition
Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets.
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| - Definition
Tabular disclosure of assets, excluding financial assets and goodwill, lacking physical substance with a finite life, by either major class or business segment.
+ References
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| - Definition
Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 45 -Subparagraph c -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 Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 47 -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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13854-109267Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 45 -Subparagraph e -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.
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