XML 66 R65.htm IDEA: XBRL DOCUMENT v3.3.0.814

Retirement Plans (Accumulated and Projected Benefit Obligations) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 30, 2014
Pension Plans with accumulated benefit obligations in excess of plan assets
Projected benefit obligation	$ 427.0	$ 459.9
Accumulated benefit obligation	427.0	459.9
Fair value of plan assets	381.3	407.6
Pension plans with plan assets in excess of accumulated benefit obligations
Projected benefit obligation	1.2	1.6
Accumulated benefit obligation	1.2	1.6
Fair value of plan assets	$ 2.1	$ 2.9

X

- Definition

Defined Benefit Plan, Pension Plans with Plan Assets in Excess of Accumulated Benefit Obligations [Abstract]

+ References

No definition available.

+ Details

Name:	mwa_DefinedBenefitPlanPensionPlansWithPlanAssetsInExcessOfAccumulatedBenefitObligationsAbstract
Namespace Prefix:	mwa_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Defined Benefit Plan, Pension Plans With Plan Assets In Excess Of Accumulated Benefit Obligations, Aggregate Accumulated Benefit Obligation

+ References

No definition available.

+ Details

Name:	mwa_DefinedBenefitPlanPensionPlansWithPlanAssetsInExcessOfAccumulatedBenefitObligationsAggregateAccumulatedBenefitObligation
Namespace Prefix:	mwa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Defined Benefit Plan, Pension Plans With Plan Assets In Excess Of Accumulated Benefit Obligations, Aggregate Fair Value of Plan Assets

+ References

No definition available.

+ Details

Name:	mwa_DefinedBenefitPlanPensionPlansWithPlanAssetsInExcessOfAccumulatedBenefitObligationsAggregateFairValueOfPlanAssets
Namespace Prefix:	mwa_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Defined Benefit Plan, Pension Plans With Plan Assets In Excess Of Accumulated Benefit Obligations, Aggregate Projected Benefit Obligation

+ References

No definition available.

+ Details

Name:	mwa_DefinedBenefitPlanPensionPlansWithPlanAssetsInExcessOfAccumulatedBenefitObligationsAggregateProjectedBenefitObligation
Namespace Prefix:	mwa_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 715



-SubTopic 20



-Section 55



-Paragraph 17



-URI http://asc.fasb.org/extlink&oid=58242635&loc=d3e4179-114921



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 715



-SubTopic 20



-Section 50



-Paragraph 3



-Subparagraph (b)



-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2417-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

If aggregate disclosures are presented, the aggregate fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 715



-SubTopic 20



-Section 55



-Paragraph 17



-URI http://asc.fasb.org/extlink&oid=58242635&loc=d3e4179-114921



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 715



-SubTopic 20



-Section 50



-Paragraph 3



-Subparagraph (b)



-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2417-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

If aggregate disclosures are presented, the aggregate projected benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 715



-SubTopic 20



-Section 50



-Paragraph 3



-Subparagraph (b)



-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2417-114920



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 715



-SubTopic 20



-Section 55



-Paragraph 17



-URI http://asc.fasb.org/extlink&oid=58242635&loc=d3e4179-114921

+ Details

Name:	us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant