| **Segment Reporting Segment Reporting - Table 5 (Details) - USD ($) $ in Millions** | 3 Months Ended | 6 Months Ended |
|-------------------------------------------------------------------------------------|----------------|----------------|
||
| **Segment Reporting, Revenue Reconciling Item [Line Items]**                        |           |           |   |   |
| Net operating revenues                                                              | $ 920.7        | $ 764.4        | $ 1,830.5 | $ 1,505.0 |
| Inpatient Rehabilitation Hospital [Member]                                          |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**                        |           |           |   |   |
| Net operating revenues                                                              | 752.6          | 645.3          | 1,501.8 | 1,275.6 |
| Inpatient [Member]                                                                  |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**                        |           |           |   |   |
| Net operating revenues                                                              | 721.2          | 618.7          | 1,440.5 | 1,225.3 |
| Outpatient and other [Member]                                                       |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**                        |           |           |   |   |
| Net operating revenues                                                              | 31.4           | 26.6           | 61.3 | 50.3 |
| Home Health and Hospice [Member]                                                    |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**                        |           |           |   |   |
| Net operating revenues                                                              | 168.1          | 119.1          | 328.7 | 229.4 |
| Home health [Member]                                                                |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**                        |           |           |   |   |
| Net operating revenues                                                              | 157.1          | 111.5          | 308.0 | 215.4 |
| Hospice [Member]                                                                    |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**                        |           |           |   |   |
| Net operating revenues                                                              | $ 11.0         | $ 7.6          | $ 20.7 | $ 14.0 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of revenues recognized by the entity from providing services to in-patients, outpatients, residents in facilities owned or operated by the entity, from insurance premiums, or from goods provided or services performed.
+ References
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) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
+ Details**Name:**us-gaap_SegmentReportingRevenueReconcilingItemLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=hls_InpatientMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=hls_HomehealthMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=hls_HospiceMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |