Name:	reg_GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes1
Namespace Prefix:	reg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Net proceed from the sale of real estate that is held for investment.

No definition available.

Name:	reg_NetProceedsFromSaleOfRealEstateHeldForInvestment
Namespace Prefix:	reg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Number of properties classified as held for sale.

No definition available.

Name:	reg_NumberOfPropertiesClassifiedAsHeldForSale
Namespace Prefix:	reg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of Real Estate Properties Sold During the period.

No definition available.

Name:	reg_NumberOfRealEstatePropertiesSold
Namespace Prefix:	reg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Percentage of limited partnership interest sold.

No definition available.

Name:	reg_PercentageOfLimitedPartnershipInterestSold
Namespace Prefix:	reg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

Name:	us-gaap_ImpairmentOfRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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.

No definition available.

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=reg_LandParcelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RealEstatePropertiesAxis=us-gaap_WhollyOwnedPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=srt_RetailSiteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: