| **Capitalization (Narrative) (Details) - Aqua Pennsylvania, Inc [Member] - USD ($)** | 1 Months Ended |
|--------------------------------------------------------------------------------------|----------------|
||
| First Mortgage Bonds [Member]                                                        |           |   |
| **Debt Instrument [Line Items]**                                                     |           |   |
| Face Amount                                                                          |           | $ 50,000,000 |
| First Mortgage Bonds Due In 2042 [Member]                                            |           |   |
| **Debt Instrument [Line Items]**                                                     |           |   |
| Face Amount                                                                          |           | $ 10,000,000 |
| Maturity Year                                                                        |           | 2042 |
| Interest Rate                                                                        |           | 3.65% |
| First Mortgage Bonds Due In 2044 [Member]                                            |           |   |
| **Debt Instrument [Line Items]**                                                     |           |   |
| Face Amount                                                                          |           | $ 40,000,000 |
| Maturity Year                                                                        |           | 2044 |
| Interest Rate                                                                        |           | 3.69% |
| First Mortgage Bonds [Member] | Subsequent Event [Member]                            |           |   |
| **Debt Instrument [Line Items]**                                                     |           |   |
| Face Amount                                                                          | $ 80,000,000   |   |
| First Mortgage Bonds Due In 2055 [Member] | Subsequent Event [Member]                |           |   |
| **Debt Instrument [Line Items]**                                                     |           |   |
| Face Amount                                                                          | $ 40,000,000   |   |
| Maturity Year                                                                        | 2055           |   |
| Interest Rate                                                                        | 4.04%          |   |
| First Mortgage Bonds Due In 2057 [Member] | Subsequent Event [Member]                |           |   |
| **Debt Instrument [Line Items]**                                                     |           |   |
| Face Amount                                                                          | $ 40,000,000   |   |
| Maturity Year                                                                        | 2057           |   |
| Interest Rate                                                                        | 4.06%          |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Face (par) amount of debt instrument at time of issuance.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399
+ Details**Name:**us-gaap_DebtInstrumentFaceAmount**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
+ Details**Name:**us-gaap_DebtInstrumentInterestRateStatedPercentage**Namespace Prefix:**us-gaap_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**instant |
| 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_DebtInstrumentLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Debt Instrument, Maturity Year
+ References
No definition available.
+ Details**Name:**wtr_DebtInstrumentMaturityYear**Namespace Prefix:**wtr_**Data Type:**xbrli:gYearItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=wtr_AquaPennsylvaniaIncMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DebtInstrumentAxis=wtr_FirstMortgageBondsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DebtInstrumentAxis=wtr_FirstMortgageBondsBMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DebtInstrumentAxis=wtr_FirstMortgageBondsCMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DebtInstrumentAxis=wtr_FirstMortgageBondsDMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------|
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