XML 59 R43.htm IDEA: XBRL DOCUMENT
v3.20.2

Retirement Plans (Tables) | 12 Months Ended
--- | ---
Sep. 30, 2020
Retirement Benefits [Abstract] |
Schedule of Net Periodic Benefit Cost | The components of net periodic benefit cost for our Pension Plans are presented below.
| 2020 |  | 2019 |  | 2018 |  |  |  |
| (in millions)
Service cost | $ | 1.5 |  |  | $ | 1.6 |  |  | $ | 1.8 |  |  |  |  |
Components of net periodic cost (benefit) excluded from operating income: |  |  |  |  |  |  |  |  |
Interest cost | 11.2 |  |  | 13.9 |  |  | 14.3 |  |  |  |  |
Expected return on plan assets | (16.9) |  |  | (16.2) |  |  | (16.5) |  |  |  |  |
Amortization of actuarial net loss | 2.8 |  |  | 1.9 |  |  | 3.2 |  |  |  |  |
Pension settlement | — |  |  | 0.7 |  |  | — |  |  |  |  |
Other | (0.1) |  |  | 0.1 |  |  | — |  |  |  |  |
Pension costs (benefit) other than service | (3.0) |  |  | 0.4 |  |  | 1.0 |  |  |  |  |
Net periodic benefit cost (benefit) | $ | (1.5) |  |  | $ | 2.0 |  |  | $ | 2.8 |  |  |  |  |
Schedule of Accumulated and Projected Benefit Obligations | P
Schedule Of Defined Benefit Plans Disclosures | Amounts recognized for Pension Plans are presented below.
| 2020 |  | 2019
| (in millions)
Projected benefit obligations: |  |  |
Beginning of year | $ | 356.6 |  |  | $ | 333.4 |
Service cost | 1.5 |  |  | 1.6 |
Interest cost | 11.2 |  |  | 13.9 |
Actuarial gain | 13.7 |  |  | 38.2 |
Benefits paid | (23.5) |  |  | (23.9) |
Currency translation | — |  |  | (0.1) |
Decrease in obligation due to curtailment / settlement | — |  |  | (6.5) |
End of year | $ | 359.5 |  |  | $ | 356.6 |
Accumulated benefit obligations at end of year | $ | 359.5 |  |  | $ | 356.6 |
Plan assets: |  |  |
Beginning of year | $ | 351.6 |  |  | $ | 343.5 |
Actual return on plan assets | 32.2 |  |  | 38.6 |
Employer contributions | 0.1 |  |  | 0.6 |
Currency translation | — |  |  | (0.5) |
Benefits paid | (23.5) |  |  | (23.9) |
Settlements | — |  |  | (6.5) |
Other | — |  |  | (0.2) |
End of year | $ | 360.4 |  |  | $ | 351.6 |
Accrued benefit cost at end of year: |  |  |
Funded (unfunded) status | $ | 0.9 |  |  | $ | (5.0) |
Recognized on balance sheet: |  |  |
Other noncurrent assets | $ | 0.9 |  |  | $ | — |
Other noncurrent liabilities | — |  |  | (5.0) |
| $ | 0.9 |  |  | $ | (5.0) |
Recognized in accumulated other comprehensive loss, before tax: |  |  |
Net actuarial loss | 74.0 |  |  | 78.4 |
| $ | 74.0 |  |  | $ | 78.4 |
Schedule of Pension and Other Postretirement Benefits Activity in Accumulated Other Comprehensive Income (Loss) [Table Text Block] | lan activity in accumulated other comprehensive loss, before tax, in 2020 is presented below, in millions.
Balance at beginning of year | $ | 78.4 |
Actuarial gain | (1.6) |
Prior year actuarial loss amortization to net periodic cost | (2.8) |
Balance at end of year | $ | 74.0 |
Schedule of Assumptions Used | A summary of key assumptions for the valuations of our Pension Plans is below.
| 2020 |  | 2019 |  | 2018
Weighted average used to determine benefit obligations: |  |  |  |  |
Discount rate | 2.84 | % |  | 3.26 | % |  | 4.37 | %
Weighted average used to determine net periodic cost: |  |  |  |  |
Discount rate | 3.26 | % |  | 4.37 | % |  | 3.88 | %
Expected return on plan assets | 5.00 | % |  | 4.93 | % |  | 4.68 | %
Schedule of Strategic Allocation of Plan Assets [Table Text Block] | This trust’s strategic asset allocations, tactical range at September 30, 2020 and actual asset allocations are presented below.
| Strategic asset allocation |  |  |  |  |  |  | Actual asset allocations at
|  |  |  |  |  |  | September 30,
|  | Tactical range |  | 2020 |  | 2019 |  | 2018
Fixed income investments | 80 | % |  | 75 |  | - | 80 | % |  |  | 78 | % |  | 79 | % |  | 77 | %
Equity investments | 20 |  |  | 15 |  | - | 20 | % |  |  | 21 |  |  | 19 |  |  | 21 |
Cash | — |  |  | 0 |  | - | 5 | % |  |  | 1 |  |  | 2 |  |  | 2 |
| 100 | % |  |  |  |  |  |  | 100 | % |  | 100 | % |  | 100 | %
Schedule of Allocation of Plan Assets | The assets of the Plan by level within the fair value hierarchy are presented below.
| September 30, 2020
| Level 1 |  | Level 2 |  |  |  | Total
| (in millions)
Fixed income | $ | — |  |  | $ | 280.3 |  |  |  |  | $ | 280.3 |
Equity: |  |  |  |  |  |  |
Large cap index funds | — |  |  | 32.8 |  |  |  |  | 32.8 |
Mid cap index funds | — |  |  | 13.5 |  |  |  |  | 13.5 |
Small cap growth funds | — |  |  | 12.7 |  |  |  |  | 12.7 |
International stocks: |  |  |  |  |  |  |
Mutual funds | 7.4 |  |  | — |  |  |  |  | 7.4 |
International funds | — |  |  | 10.4 |  |  |  |  | 10.4 |
Total equity | 7.4 |  |  | 69.4 |  |  |  |  | 76.8 |
Cash and cash equivalents | 3.3 |  |  | — |  |  |  |  | 3.3 |
| $ | 10.7 |  |  | $ | 349.7 |  |  |  |  | $ | 360.4 |
| September 30, 2019
| Level 1 |  | Level 2 |  |  |  | Total
| (in millions)
Fixed income | $ | — |  |  | $ | 277.8 |  |  |  |  | $ | 277.8 |
Equity: |  |  |  |  |  |  |
Large cap index funds | — |  |  | 29.8 |  |  |  |  | 29.8 |
Mid cap index funds | — |  |  | 9.8 |  |  |  |  | 9.8 |
Small cap growth funds | — |  |  | 9.6 |  |  |  |  | 9.6 |
International stocks: |  |  |  |  |  |  |
Mutual funds | 6.9 |  |  | — |  |  |  |  | 6.9 |
International funds | — |  |  | 10.3 |  |  |  |  | 10.3 |
Total equity | 6.9 |  |  | 59.5 |  |  |  |  | 66.4 |
Cash and cash equivalents | 7.4 |  |  | — |  |  |  |  | 7.4 |
| $ | 14.3 |  |  | $ | 337.3 |  |  |  |  | $ | 351.6 |
Schedule of Expected Benefit Payments | Our estimated future pension benefit payments are presented below in millions.
2021 | $ | 24.7 |
2022 | 24.5 |
2023 | 24.1 |
2024 | 23.7 |
2025 | 23.2 |
2026-2030 | 108.2 |

X
- Definition Schedule of Strategic Allocation of Plan Assets [Table Text Block] + References No definition available. + Details
Name: | mwa_ScheduleOfStrategicAllocationOfPlanAssetsTableTextBlock
Namespace Prefix: | mwa_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of benefit obligations including accumulated benefit obligation and projected benefit obligation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfAccumulatedAndProjectedBenefitObligationsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(5) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of assumption used to determine benefit obligation and net periodic benefit cost of defined benefit plan. Includes, but is not limited to, discount rate, rate of compensation increase, expected long-term rate of return on plan assets and interest crediting rate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfAssumptionsUsedTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the changes in plan assets and benefit obligations recognized in other comprehensive income (loss) during the period. + References No definition available. + Details
Name: | us-gaap_ScheduleOfDefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of one or more of the entity's defined benefit pension plans or one or more other defined benefit postretirement plans, separately for pension plans and other postretirement benefit plans including the entity's schedule of fair value of plan assets for defined benefit or other postretirement plans. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2439-114920 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2410-114920 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2417-114920 + Details
Name: | us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration