No definition available.

Name:	ato_AlternativeRevenueProgramLineItems
Namespace Prefix:	ato_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of cash pledged as collateral against derivative liabilities.

No definition available.

Name:	ato_DerivativeCashCollateral
Namespace Prefix:	ato_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Length of Pipeline

No definition available.

Name:	ato_LengthOfPipeline
Namespace Prefix:	ato_
Data Type:	dtr-types:lengthItemType
Balance Type:	na
Period Type:	instant

Number of Asset Management Plans Under Management

No definition available.

Name:	ato_NumberOfAssetManagementPlansUnderManagement
Namespace Prefix:	ato_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Rate case revenue benchmark as set in the APT rate case filing and part of our regulatory mechanism. This revenue benchmark is used in calculating the total revenue to be billed or returned to customers.

No definition available.

Name:	ato_RateCaseRevenueBenchmark
Namespace Prefix:	ato_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

APT has a regulatory mechanism that requires that we share with its tariffed customers a set percentage, as determined through the rate case filings, of the difference between the total non-tariffed revenues earned during a test period and a revenue benchmark.

No definition available.

Name:	ato_RegulatoryMechanismThreshold
Namespace Prefix:	ato_
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Self Insured Retention Deductible

No definition available.

Name:	ato_SelfInsuredRetentionDeductible
Namespace Prefix:	ato_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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Reference 2: http://www.xbrl.org/2003/role/exampleRef
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Composite depreciation rate for public utility plants in service.

No definition available.

ATMOS ENERGY CORP 10-K