XML 139 R117.htm IDEA: XBRL DOCUMENT v3.25.4

Segment Information - Additional Information (Details)	12 Months Ended
	Dec. 31, 2025 segment state
Segment Reporting Information [Line Items]
Number of reportable segment | segment	1
Regulated Businesses
Segment Reporting Information [Line Items]
Number of states in which entity provides water and wastewater services | state	14

X

- Definition

Number Of States In Which Entity Provides Water And Wastewater Services

+ References

No definition available.

+ Details

Name:	awk_NumberOfStatesInWhichEntityProvidesWaterAndWastewaterServices
Namespace Prefix:	awk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 47
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-47

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 54
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-54

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-18

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

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

X

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=awk_RegulatedBusinessMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: