XML 34 R51.htm IDEA: XBRL DOCUMENT v3.19.3

Revenue from Contracts with Customers Narrative (Details)	12 Months Ended
	Sep. 30, 2019
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Percent of Revenue by Recognition Timing	2.00%
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Percent of Revenue by Recognition Timing	98.00%

X

- Definition

Percent of Revenue by Recognition Timing

+ References

No definition available.

+ Details

Name:	mwa_PercentofRevenuebyRecognitionTiming
Namespace Prefix:	mwa_
Data Type:	num:percentItemType
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_DisaggregationOfRevenueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_TimingOfTransferOfGoodOrServiceAxis=us-gaap_TransferredOverTimeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_TimingOfTransferOfGoodOrServiceAxis=us-gaap_TransferredAtPointInTimeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: