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Contingencies and Legal Proceedings Contingencies (Details) $ in Millions | 9 Months Ended |
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Jun. 30, 2021 USD ($) reactors Procedures Insurance_layers | Sep. 30, 2020 USD ($)
Loss Contingencies |  |
Nuclear liability insurance | $ 450 |
Assessment from licensees for each licensed reactor | $ 138 |
Number of licensed reactors in US | reactors | 95 |
Nuclear accident assessment limitation per year per unit | $ 20 |
Maximum assessment per nuclear incident | 963 |
Total amount of protection available | 13,500 |
Amount of insurance available for loss at any one site | 2,100 |
Maximum amount of retrospective premiums | 128 |
Maximum idemnity if a covered accident takes or keeps a nuclear unit offline | 490 |
Maximum retrospective premiums | 43 |
Estimated future decommissioning cost | $ 6,952 | $ 6,785
Number of procedures for determining estimates for the costs of nuclear decommissioning | Procedures | 2 |
Possible additional future costs for compliance with Clean Air Act requirements | $ 139 |
Possible additional future costs for compliance with CCR requirements | 800 |
Possible additional future costs for compliance with Clean Water requirements. | 156 |
Estimated liability for cleanup and environmental work |  | 14
Amount of insurance available for loss at any one site (top range) | 2,800 |
Long-term debt of VIEs (including current maturities), net | $ 1,346 | 1,419
The U.S. Congress is required to take action if these layes are exhausted | Insurance_layers | 2 |
Nuclear |  |
Loss Contingencies |  |
Estimated future decommissioning cost | $ 3,396 | 3,278
Non-nuclear |  |
Loss Contingencies |  |
Estimated future decommissioning cost | 3,556 | $ 3,507
Environmental Agreements |  |
Loss Contingencies |  |
Amount invested in certain environmental projects | 280 |
General |  |
Loss Contingencies |  |
Legal loss contingency accrual | $ 14 |

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- Definition The amount of property, decommissioning, and decontamination insurance available for loss at any one site to cover the cost of stabilizing or shutting down a reactor after an accident. + References No definition available. + Details
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- Definition An assessment from licensees for each licensed nuclear reactor in the United States to fund the second layer, the Secondary Financial Program. + References No definition available. + Details
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- Definition The maximum idemnity per unit if an accident covered by the policy tasks or keeps a nuclear unit offline. + References No definition available. + Details
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- Definition For the first layer of protection all NRC nuclear plant licensees purchase nuclear insurance from American Nuclear Insurers for each nuclear plant with an operating license. + References No definition available. + Details
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- Definition Number of procedures for determining estimates for the costs of nuclear decommissioning + References No definition available. + Details
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