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Benefit Plans Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2020
Pension Benefits |  |  |
Defined Benefit Plan Disclosure |  |  |
Service cost | $ 53 | $ 57 | $ 55
DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncome | 378 | 368 | 415
DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncome | (435) | (493) | (488)
DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfPriorServiceCostCreditStatementOfIncome | (93) | (97) | (97)
DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncome | 392 | 452 | 436
Net periodic benefit cost as acutarially determined | 295 | 287 | 321
Amount expensed (capitalized) due to actions of regulator | (13) | (19) | 15
Total net period benefit cost | 308 | 306 | 306
Other Post-retirement Benefits |  |  |
Defined Benefit Plan Disclosure |  |  |
Service cost | 17 | 18 | 16
DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncome | 15 | 16 | 16
Expected return on plan assets | 0 | 0 | 0
DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfPriorServiceCostCreditStatementOfIncome | (17) | (18) | (24)
DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncome | 5 | (11) | (10)
Net periodic benefit cost as acutarially determined | 20 | 27 | 18
Amount expensed (capitalized) due to actions of regulator | 0 | 0 | 0
Total net period benefit cost | $ 20 | $ 27 | $ 18

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- Definition The total amount of net periodic benefit cost actuarilly determined for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. + References No definition available. + Details
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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(3) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123453770&loc=SL108413299-114919 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(3) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 + Details
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