TENNESSEE VALLEY AUTHORITY, 10-K filed on 11/15/2022
Annual Report
v3.22.2.2
DEI Document
shares in Millions, $ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
shares
Document Information [Line Items]  
Entity Registrant Name TENNESSEE VALLEY AUTHORITY
Entity Central Index Key 0001376986
Entity Filer Category Non-accelerated Filer
Document Type 10-K
Document Fiscal Year Focus 2022
Document Fiscal Period Focus FY
Amendment Flag false
Entity Common Stock, Shares Outstanding | shares 0
Entity Emerging Growth Company false
Entity Shell Company false
Entity Well-known Seasoned Issuer No
Entity Public Float | $ $ 0
Document Transition Report false
Entity File Number 000-52313
Entity Tax Identification Number 62-0474417
Entity Address, State or Province TN
Entity Address, City or Town Knoxville
Entity Address, Address Line One 400 W. Summit Hill Drive
Local Phone Number 632-2101
City Area Code (865)
Entity Address, Postal Zip Code 37902 (Zip Code)
Entity Interactive Data Current Yes
ICFR Auditor Attestation Flag true
Entity Incorporation, State or Country Code X1
Entity Current Reporting Status Yes
Document Annual Report true
Document Period End Date Sep. 30, 2022
Entity Small Business false
Entity Voluntary Filers No
Current Fiscal Year End Date --09-30
v3.22.2.2
Audit Information
 12 Months Ended
Sep. 30, 2022
Auditor [Line Items]  
Auditor Name Ernst & Young LLP
Auditor Location Chattanooga, Tennessee
Auditor Firm ID 42
v3.22.2.2
CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Operating revenues      
Electric revenue $ 12,371 $ 10,357 $ 10,104
Other revenue 169 146 145
Revenue from sales of electricity 12,540 10,503 10,249
Operating expenses      
Fuel 2,567 1,737 1,584
Purchased power 1,921 984 880
Operating and maintenance 2,986 2,890 2,720
Depreciation and amortization 2,054 1,533 1,826
Tax equivalents 601 514 528
Total operating expenses 10,129 7,658 7,538
Operating income 2,411 2,845 2,711
Other income (expense), net 7 13 36
Defined Benefit Plan, Other Cost (Credit) 258 258 253
Interest expense      
Interest expense 1,052 1,088 1,142
Net income (loss) 1,108 1,512 1,352
ALABAMA      
Operating revenues      
Electric revenue 1,778 1,508 1,439
GEORGIA      
Operating revenues      
Electric revenue 299 254 249
KENTUCKY      
Operating revenues      
Electric revenue 821 655 624
MISSISSIPPI      
Operating revenues      
Electric revenue 1,182 984 941
NORTH CAROLINA      
Operating revenues      
Electric revenue 87 66 65
TENNESSEE      
Operating revenues      
Electric revenue 8,137 6,841 6,740
VIRGINIA      
Operating revenues      
Electric revenue $ 48 $ 42 $ 42
v3.22.2.2
CONSOLIDATED BALANCE SHEETS - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Current assets    
Cash and Cash Equivalents, at Carrying Value $ 500 $ 499
Accounts receivable, net 2,007 1,566
Inventories, net 1,072 950
Regulatory assets 138 196
Other current assets 257 287
Total current assets 3,974 3,498
Property, plant, and equipment    
Completed plant 66,442 66,411
Less accumulated depreciation (34,239) (34,663)
Net completed plant 32,203 31,748
Construction in progress 2,535 2,458
Nuclear fuel 1,492 1,566
Finance lease, Right-of-Use-Asset 630 692
Total property, plant, and equipment, net 36,860 36,464
Long-term Investments 3,671 4,053
Regulatory and other long-term assets    
Regulatory assets 6,134 7,956
Operating Lease, Right-of-Use Asset 155 165
Other long-term assets 394 320
Total regulatory and other long-term assets 6,683 8,441
Total assets 51,188 52,456
Current liabilities    
Accounts payable and accrued liabilities 2,466 2,215
Accrued interest 273 282
Asset Retirement Obligation, Current 275 266
Leaseback obligations, current 0 25
Regulatory liabilities 391 340
Short-term debt, net of discounts 1,172 780
Total Current maturities of power bonds issued at par 29 1,028
Current maturities of long-term debt of variable interest entities issued at par 39 43
Total current liabilities 4,645 4,979
Other liabilities    
Post-retirement and post-employment benefit obligations 3,072 5,045
Asset retirement obligations 6,887 6,736
Other long-term liabilities 1,485 2,041
Non-current regulatory liabilities 172 40
Total other liabilities 12,244 14,549
Long-term debt, net    
Long-term power bonds, net 17,826 17,457
Long-term debt of variable interest entities, net 968 1,006
Total long-term debt, net 18,794 18,463
Total liabilities 35,683 37,991
Proprietary capital    
Power program appropriation investment 258 258
Power program retained earnings 14,800 13,689
Total power program proprietary capital 15,058 13,947
Nonpower programs appropriation investment, net 533 540
Accumulated other comprehensive income (loss) (86) (22)
Total proprietary capital 15,505 14,465
Total liabilities and proprietary capital 51,188 52,456
Finance Lease, Liability, Noncurrent $ 628 $ 687
v3.22.2.2
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents $ 520 $ 518 $ 521
Cash flows from operating activities      
Net income (loss) 1,108 1,512 1,352
Adjustments to reconcile net income (loss) to net cash provided by operating activities      
Depreciation and amortization (including amortization of debt issuance costs and premiums/discounts) 2,076 1,555 1,848
Amortization of nuclear fuel cost 347 383 388
Non-cash retirement benefit expense 328 333 324
Regulatory asset amount expensed (70) (72) (21)
Changes in current assets and liabilities      
Accounts receivable, net (412) (18) 259
Inventories and other current assets, net (163) 42 (12)
Accounts payable and accrued liabilities 282 178 (38)
Accrued interest (7) (18) 1
Pension contributions (308) (306) (305)
Settlements of asset retirement obligations (291) (242) 114
Other, net (82) (91) (46)
Net cash provided by operating activities 2,948 3,256 3,636
Cash flows from investing activities      
Construction expenditures (2,361) (1,963) (1,643)
Nuclear fuel expenditures (283) (354) (342)
Purchases of investments (51) (50) (49)
Loans and other receivables      
Repayments 15 9 7
Other, net 26 27 20
Net cash used in investing activities (2,663) (2,338) (2,015)
Long-term debt      
Issues of power bonds 484 500 997
Redemptions and repurchases of power bonds (1,028) (1,860) (1,427)
Payments on debt of variable interest entities (43) (41) (39)
Redemptions of Notes Payable 0 0 23
Short-term debt issues (redemptions), net 392 723 (865)
Finance Lease, Principal Payments 85 250 55
Financing costs, net (3) (2) (4)
Other, net 0 9 (6)
Net cash (used in) provided by financing activities (283) (921) (1,422)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect 2 (3) 199
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total 2    
Advances on loans receivable $ (9) $ (7) $ (8)
v3.22.2.2
CONSOLIDATED STATEMENTS OF CHANGES IN PROPRIETARY CAPITAL - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Balance at beginning of year $ 14,465 $ 12,932 $ 11,625
Net income (loss) 1,108 1,512 1,352
Total other comprehensive income (loss) (64) 29 (39)
Return on power program appropriation investment (4) (4) (6)
Balance at end of year 15,505 14,465 12,932
Power Program Appropriation Investment      
Balance at beginning of year 258 258 258
Net income (loss) 0 0 0
Total other comprehensive income (loss) 0 0 0
Return on power program appropriation investment 0 0 0
New Accounting Standard - CECL   0  
Balance at end of year 258 258 258
Power Program Retained Earnings      
Balance at beginning of year 13,689 12,177 10,823
Net income (loss) 1,115 1,520 1,360
Total other comprehensive income (loss) 0 0 0
Return on power program appropriation investment (4) (4) (6)
New Accounting Standard - CECL   (4)  
Balance at end of year 14,800 13,689 12,177
Nonpower Programs Appropriation Investment, Net      
Balance at beginning of year 540 548 556
Net income (loss) (7) (8) (8)
Total other comprehensive income (loss) 0 0 0
Return on power program appropriation investment 0 0 0
New Accounting Standard - CECL   0  
Balance at end of year 533 540 548
Accumulated Other Comprehensive Income (Loss) Net Gains (Losses) on Cash Flow Hedges      
Balance at beginning of year (22) (51) (12)
Net income (loss) 0 0 0
Total other comprehensive income (loss) (64) 29 (39)
Return on power program appropriation investment 0 0 0
New Accounting Standard - CECL   0  
Balance at end of year $ (86) $ (22) $ (51)
v3.22.2.2
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) Statement - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Statement of Comprehensive Income [Abstract]      
Net income (loss) $ 1,108 $ 1,512 $ 1,352
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax (157) 126 (1)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax 93 (97) (38)
Total other comprehensive income (loss) (64) 29 (39)
Total comprehensive income (loss) $ 1,044 $ 1,541 $ 1,313
v3.22.2.2
Supplemental Cash Flow Information
 12 Months Ended
Sep. 30, 2022
Supplemental Cash Flow Information [Abstract]  
Supplemental Cash Flow Information Interest paid was $1.1 billion for each of 2022, 2021, and 2020. These amounts differ from interest expense in certain years due to the timing of payments. There was no interest capitalized in 2022, 2021, or 2020.    Construction in progress and asset retirement obligation project accruals and nuclear fuel expenditures included in Accounts payable and accrued liabilities at September 30, 2022, 2021, and 2020 were $629 million, $637 million, and $398 million, respectively, and are excluded from the Statements of Consolidated Cash Flows for the years ended September 30, 2022, 2021, and 2020 as non-cash investing activities. 
    Excluded from the Statement of Consolidated Cash Flows for the year ended September 30, 2021, were non-cash investing and financing activities of $233 million related primarily to an increase in lease assets and liabilities incurred for a finance lease that was amended in March 2021. Excluded from the Statement of Consolidated Cash Flows for the year ended September 30, 2020, as non-cash financing activities, was $394 million related to lease obligations incurred primarily in connection with a PPA. See Note 8 — Leases for further information regarding TVA's finance leases. Also excluded from the Statement of Consolidated Cash Flows for the year ended September 30, 2020, were $80 million and $73 million as non-cash financing and investing activities, respectively, due to derecognition of the Paradise pipeline financing obligation and asset. No material finance leases were entered into during the year ended September 30, 2022.

    Cash flows from swap contracts that are accounted for as hedges are classified in the same category as the item being hedged or on a basis consistent with the nature of the instrument.
v3.22.2.2
Supplemental Cash Flow Information - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Supplemental Cash Flow Information      
Interest paid $ 1,100 $ 1,100 $ 1,100
Capital lease obligations incurred   394  
Non-cash financing activities   80  
Non-cash investing activities   73  
Lease assets obtained in exchange for lease obligations - finance 0 233 394
Accounts payable and accrued liabilities      
Supplemental Cash Flow Information      
Construction in progress and Nuclear fuel expenditures $ 629 $ 637 $ 398
v3.22.2.2
Summary of Significant Accounting Policies [Text Block]
 12 Months Ended
Sep. 30, 2022
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies
General

The Tennessee Valley Authority ("TVA") is a corporate agency and instrumentality of the United States ("U.S.") that was created in 1933 by federal legislation in response to a proposal by President Franklin D. Roosevelt.  TVA was created to, among other things, improve navigation on the Tennessee River, reduce the damage from destructive flood waters within the Tennessee River system and downstream on the lower Ohio and Mississippi Rivers, further the economic development of TVA's service area in the southeastern U.S., and sell the electricity generated at the facilities TVA operates. Today, TVA operates the nation's largest public power system and supplies power in most of Tennessee, northern Alabama, northeastern Mississippi, and southwestern Kentucky and in portions of northern Georgia, western North Carolina, and southwestern Virginia to a population of approximately 10 million people.

    TVA also manages the Tennessee River, its tributaries, and certain shorelines to provide, among other things, year-round navigation, flood damage reduction, and affordable and reliable electricity. Consistent with these primary purposes, TVA also manages the river system and public lands to provide recreational opportunities, adequate water supply, improved water quality, cultural and natural resource protection, and economic development. TVA performs these management duties in cooperation with other federal and state agencies that have jurisdiction and authority over certain aspects of the river system. In addition, the TVA Board of Directors ("TVA Board") has established two councils — the Regional Resource Stewardship Council and the Regional Energy Resource Council — to advise TVA on its stewardship activities in the Tennessee Valley and its energy resource activities.

The power program has historically been separate and distinct from the stewardship programs.  It is required to be self-supporting from power revenues and proceeds from power financings, such as proceeds from the issuance of bonds, notes, or other evidences of indebtedness (collectively, "Bonds").  Although TVA does not currently receive Congressional appropriations, it is required to make annual payments to the United States Department of the Treasury ("U.S. Treasury") as a return on the government's appropriation investment in TVA's power facilities (the "Power Program Appropriation Investment").  In the 1998 Energy and Water Development Appropriations Act, Congress directed TVA to fund essential stewardship activities related to its management of the Tennessee River system and nonpower or stewardship properties with power revenues in the event that there were insufficient appropriations or other available funds to pay for such activities in any fiscal year.  Congress has not
provided any appropriations to TVA to fund such activities since 1999.  Consequently, during 2000, TVA began paying for essential stewardship activities primarily with power revenues, with the remainder funded with user fees and other forms of revenues derived in connection with those activities.  The activities related to stewardship properties do not meet the criteria of an operating segment under accounting principles generally accepted in the United States of America ("GAAP").  Accordingly, these assets and properties are included as part of the power program, TVA's only operating segment.

Power rates are established by the TVA Board as authorized by the Tennessee Valley Authority Act of 1933, as amended, 16 U.S.C. §§ 831-831ee ("TVA Act").  The TVA Act requires TVA to charge rates for power that will produce gross revenues sufficient to provide funds for operation, maintenance, and administration of its power system; payments to states and counties in lieu of taxes ("tax equivalents"); debt service on outstanding indebtedness; payments to the U.S. Treasury in repayment of and as a return on the Power Program Appropriation Investment; and such additional margin as the TVA Board may consider desirable for investment in power system assets, retirement of outstanding Bonds in advance of maturity, additional reduction of the Power Program Appropriation Investment, and other purposes connected with TVA's power business.  TVA fulfilled its requirement to repay $1.0 billion of the Power Program Appropriation Investment with the 2014 payment; therefore, this repayment obligation is no longer a component of rate setting. In setting TVA's rates, the TVA Board is charged by the TVA Act to have due regard for the primary objectives of the TVA Act, including the objective that power shall be sold at rates as low as are feasible.  Rates set by the TVA Board are not subject to review or approval by any state or other federal regulatory body.

Fiscal Year

TVA's fiscal year ends September 30.  Years (2022, 2021, etc.) refer to TVA's fiscal years unless they are preceded by "CY," in which case the references are to calendar years.

Cost-Based Regulation

Since the TVA Board is authorized by the TVA Act to set rates for power sold to its customers, TVA is self-regulated. Additionally, TVA's regulated rates are designed to recover its costs.  Based on current projections, TVA believes that rates, set at levels that will recover TVA's costs, can be charged and collected.  As a result of these factors, TVA records certain assets and liabilities that result from the regulated ratemaking process that would not be recorded under GAAP for non-regulated entities.   Regulatory assets generally represent incurred costs that have been deferred because such costs are probable of future recovery in customer rates.  Regulatory liabilities generally represent obligations to make refunds to customers for previous collections for costs that are not likely to be incurred or deferral of gains that will be credited to customers in future periods.  TVA assesses whether the regulatory assets are probable of future recovery by considering factors such as applicable regulatory changes, potential legislation, and changes in technology.  Based on these assessments, TVA believes the existing regulatory assets are probable of recovery.  This determination reflects the current regulatory and political environment and is subject to change in the future.  If future recovery of regulatory assets ceases to be probable, or TVA is no longer considered to be a regulated entity, then costs would be required to be written off.  All regulatory asset write offs would be required to be recognized in earnings in the period in which future recovery ceases to be probable.

Basis of Presentation

    The accompanying consolidated financial statements, which have been prepared in accordance with GAAP, include the accounts of TVA and variable interest entities ("VIEs") of which TVA is the primary beneficiary. See Note 11 — Variable Interest Entities. Intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements requires TVA to estimate the effects of various matters that are inherently uncertain as of the date of the consolidated financial statements.  Although the consolidated financial statements are prepared in conformity with GAAP, TVA is required to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the amounts of revenues and expenses, reported during the reporting period.  Each of these estimates varies in regard to the level of judgment involved and its potential impact on TVA's financial results.  Estimates are considered critical either when a different estimate could have reasonably been used, or where changes in the estimate are reasonably likely to occur from period to period, and such use or change would materially impact TVA's financial condition, results of operations, or cash flows.

Cash, Cash Equivalents, and Restricted Cash

    Cash includes cash on hand, non-interest bearing cash, and deposit accounts. All highly liquid investments with original maturities of three months or less are considered cash equivalents. Cash and cash equivalents that are restricted, as to withdrawal or use under the terms of certain contractual agreements, are recorded in Other long-term assets on the Consolidated Balance Sheets. Restricted cash and cash equivalents include cash held in trusts that are currently restricted for TVA economic development loans and for certain TVA environmental programs in accordance with agreements related to
compliance with certain environmental regulations. See Note 21 — Commitments and Contingencies — Legal Proceedings — Environmental Agreements.

    The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported on the Consolidated Balance Sheets and Consolidated Statements of Cash Flows:
Cash, Cash Equivalents, and Restricted Cash
At September 30
(in millions)
 20222021
Cash and cash equivalents$500 $499 
Restricted cash and cash equivalents included in Other long-term assets20 19 
Total cash, cash equivalents, and restricted cash$520 $518 

Allowance for Uncollectible Accounts

TVA recognizes an allowance that reflects the current estimate for credit losses expected to be incurred over the life of the financial assets based on historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amounts. The appropriateness of the allowance is evaluated at the end of each reporting period.

To determine the allowance for trade receivables, TVA considers historical experience and other currently available information, including events such as customer bankruptcy and/or a customer failing to fulfill payment arrangements by the due date. TVA's corporate credit department also performs an assessment of the financial condition of customers and the credit quality of the receivables. In addition, TVA reviews other reasonable and supportable forecasts to determine if the allowance for uncollectible amounts should be further adjusted in accordance with the accounting guidance for Current Expected Credit Losses.

To determine the allowance for loans receivables, TVA aggregates loans into the appropriate pools based on the existence of similar risk characteristics such as collateral types and internal assessed credit risks. In situations where a loan exhibits unique risk characteristics and is no longer expected to experience similar risks to the rest of its pool, the loan will be evaluated separately. TVA derives an annual loss rate based on historical loss and then adjusts the rate to reflect TVA's consideration of available information on current conditions and reasonable and supportable future forecasts. This information may include economic and business conditions, default trends, and other internal and external factors. For periods beyond the reasonable and supportable forecast period, TVA uses the current calculated long-term average historical loss rate for the remaining life of the loan portfolio.

The allowance for uncollectible accounts was less than $1 million at both September 30, 2022 and 2021, for trade accounts receivable.  Additionally, loans receivable of $105 million and $99 million at September 30, 2022 and 2021, respectively, are included in Accounts receivable, net and Other long-term assets, for the current and long-term portions, respectively. Loans receivables are reported net of allowances for uncollectible accounts of $3 million and $4 million at September 30, 2022 and 2021, respectively.

Revenues

TVA recognizes revenue from contracts with customers to depict the transfer of goods or services to customers in an amount to which the entity expects to be entitled in exchange for those goods or services. For the generation and transmission of electricity, this is generally at the time the power is delivered to a metered customer delivery point for the customer's consumption or distribution. As a result, revenues from power sales are recorded as electricity is delivered to customers. In addition to power sales invoiced and recorded during the month, TVA accrues estimated unbilled revenues for power sales provided to five customers whose billing date occurs prior to the end of the month.  Exchange power sales are presented in the accompanying Consolidated Statements of Operations as a component of sales of electricity. Exchange power sales are sales of excess power after meeting TVA native load and directly served requirements.  Native load refers to the customers on whose behalf a company, by statute, franchise, regulatory requirement, or contract, has undertaken an obligation to serve. TVA engages in other arrangements in addition to power sales. Certain other revenue from activities related to TVA's overall mission is recorded in Other revenue. Revenues that are not related to the overall mission are recorded in Other income, net.

Inventories

Certain Fuel, Materials, and Supplies.  Materials and supplies inventories are valued using an average unit cost method. A new average cost is computed after each inventory purchase transaction, and inventory issuances are priced at the latest moving weighted average unit cost. Coal, fuel oil, and natural gas inventories are valued using an average cost method. A new weighted average cost is computed monthly, and monthly issues are priced accordingly.
Renewable Energy Certificates. TVA accounts for Renewable Energy Certificates ("RECs") using the specific identification cost method. RECs that are acquired through power purchases are recorded as inventory and charged to purchased power expense when the RECs are subsequently used or sold. TVA assigns a value to the RECs at the inception of the power purchase arrangement using a relative standalone selling price approach. RECs created through TVA-owned asset generation are recorded at zero cost.

Emission Allowances.  TVA accounts for emission allowances using the specific identification cost method. Allowances that are acquired through third party purchases are recorded as inventory at cost and charged to operating expense based on tons emitted during the respective compliance periods.  

Allowance for Inventory Obsolescence.  TVA reviews materials and supplies inventories by category and usage on a periodic basis.  Each category is assigned a probability of becoming obsolete based on the type of material and historical usage data.  TVA has a fleet-wide inventory management policy for each generation type. Based on the estimated value of the inventory, TVA adjusts its allowance for inventory obsolescence.

Property, Plant, and Equipment, and Depreciation

    Property, Plant, and Equipment. Additions to plant are recorded at cost, which includes direct and indirect costs.  The cost of current repairs and minor replacements is charged to operating expense.  Nuclear fuel, which is included in Property, plant, and equipment, is valued using the average cost method for raw materials and the specific identification method for nuclear fuel in a reactor.  Amortization of nuclear fuel in a reactor is calculated on a units-of-production basis and is included in fuel expense. When property, plant, and equipment is retired, accumulated depreciation is charged for the original cost of the assets. Gains or losses are only recognized upon the sale of land or an entire operating unit. TVA capitalizes certain costs incurred in connection with developing or obtaining internal-use software. Capitalized software costs are included in Property, plant, and equipment on the Consolidated Balance Sheets and are generally amortized over seven years.  

    Depreciation. TVA accounts for depreciation of its properties using the composite depreciation convention of accounting.  Under the composite method, assets with similar economic characteristics are grouped and depreciated as one asset. Depreciation is generally computed on a straight-line basis over the estimated service lives of the various classes of assets. The estimation of asset useful lives requires management judgment, supported by external depreciation studies of historical asset retirement experience. Depreciation rates are determined based on external depreciation studies that are updated approximately every five years. During the first quarter of 2022, TVA implemented a new depreciation study related to its completed plant.  The new study included a decline in the service life estimates of TVA’s coal-fired plants based on current planning assumptions to potentially retire the remainder of the coal-fired fleet by 2035. Implementation of the study resulted in an estimated increase to depreciation and amortization expense of approximately $345 million during 2022. This estimate represents the effect of using the new depreciation rates on the property, plant, and equipment balances at September 30, 2021, and does not include any potential impact from additions to or retirements of net completed plant, that occurred since September 30, 2021.

Depreciation expense for the years ended September 30, 2022, 2021, and 2020 was $1.8 billion, $1.4 billion, and $1.6 billion, respectively. Depreciation expense expressed as a percentage of the average annual depreciable completed plant was 2.98 percent for 2022, 2.28 percent for 2021, and 2.74 percent for 2020.  Average depreciation rates by asset class are as follows:
Property, Plant, and Equipment Depreciation Rates
At September 30
(percent)
202220212020
Asset Class
Nuclear2.72 2.38 2.38 
Coal-fired(1)
4.27 1.95 3.62 
Hydroelectric1.85 1.60 1.60 
Gas and oil-fired3.38 2.98 3.04 
Transmission1.51 1.34 1.34 
Other3.64 7.12 7.26 
Note
(1) The rates include the acceleration of depreciation related to retiring certain coal-fired units and potentially retiring the remainder of the coal-fired fleet by 2035. See Note 7 — Plant Closures.

Reacquired Rights. Property, plant, and equipment includes intangible reacquired rights, net of amortization, of $178 million and $184 million as of September 30, 2022 and 2021, respectively, related to the purchase of residual interests from lease/leaseback agreements of certain combustion turbine units ("CTs"). Reacquired rights are amortized over the estimated useful lives of the underlying CTs which range from 33 to 35 years. Amortization expense was $6 million for 2022 and $8 million for the years 2021 and 2020, and accumulated amortization at September 30, 2022 and 2021 totaled $42 million and $36 million,
respectively. At September 30, 2022, the estimated aggregate amortization expense (in millions) for each of the next five years and thereafter is shown below:

 20232024202520262027Thereafter
Reacquired Rights$6 $6 $6 $6 $6 $148 

Impairment of Assets.  TVA evaluates long-lived assets for impairment when events or changes in circumstances indicate that the carrying value of such assets may not be recoverable.  For long-lived assets, TVA bases its evaluation on impairment indicators such as the nature of the assets, the future economic benefit of the assets, any historical or future profitability measurements, regulatory approval and ability to set rates at levels that allow for recoverability of the assets, and other external market conditions or factors that may be present.  If such impairment indicators are present or other factors exist that indicate that the carrying amount of an asset may not be recoverable, TVA determines whether an impairment has occurred based on an estimate of undiscounted cash flows attributable to the asset as compared with the carrying value of the asset.  If an impairment has occurred, the amount of the impairment recognized is measured as the excess of the asset's carrying value over its fair value.  Additionally, TVA regularly evaluates construction projects.  If the project is canceled or deemed to have no future economic benefit, the project is written off as an asset impairment or, upon TVA Board approval, reclassified as a regulatory asset and amortized over the Board-approved period. See Note 7 — Plant Closures.

Leases

    TVA recognizes a lease asset and lease liability for leases with terms of greater than 12 months. Lease assets represent TVA's right to use an underlying asset for the lease term, and lease liabilities represent TVA's obligation to make lease payments arising from the lease, both of which are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date.  TVA has certain lease agreements that include variable lease payments that are based on energy production levels. These variable lease payments are not included in the measurement of the lease assets or lease liabilities but are recognized in the period in which the expenses are incurred.
    
    While not specifically structured as leases, certain power purchase agreements ("PPAs") are deemed to contain a lease of the underlying generating units when the terms convey the right to control the use of the assets. Amounts recorded for these leases are generally based on the amount of the scheduled capacity payments due over the remaining terms of the PPAs, the terms of which vary. The total lease obligations included in Accounts payable and accrued liabilities and Other long-term liabilities and Finance lease liabilities related to these agreements were $425 million and $133 million for finance and operating leases, respectively, at September 30, 2022. The total lease obligations included in Accounts payable and accrued liabilities and Other long-term liabilities and Finance lease liabilities related to these agreements were $464 million and $143 million for finance and operating leases, respectively, at September 30, 2021.

    TVA has agreements with lease and non-lease components and has elected to account for the components separately. Consideration is allocated to lease and non-lease components generally based on relative standalone selling prices.

    TVA has lease agreements which include options for renewal and early termination. The intent to renew a lease varies depending on the lease type and asset. Renewal options that are reasonably certain to be exercised are included in the lease measurements. The decision to terminate a lease early is dependent on various economic factors. No termination options have been included in TVA's lease measurements.
    
    Leases with an initial term of 12 months or less, which do not include an option to extend the initial term of the lease to greater than 12 months that TVA is reasonably certain to exercise, are not recorded on the Consolidated Balance Sheets at September 30, 2022.
    Operating leases are recognized on a straight-line basis over the term of the lease agreement. Rent expense associated with short-term leases and variable leases is recorded in Operating and maintenance expense, Fuel expense, or Purchased power expense on the Consolidated Statements of Operations. Expenses associated with finance leases result in the separate presentation of interest expense on the lease liability and amortization expense of the related lease asset on the Consolidated Statements of Operations.

Decommissioning Costs

    TVA recognizes legal obligations associated with the future retirement of certain tangible long-lived assets.  These obligations relate to fossil fuel-fired generating plants, nuclear generating plants, hydroelectric generating plants/dams, transmission structures, and other property-related assets.  Activities involved with retiring these assets could include decontamination and demolition of structures, removal and disposal of wastes, and site restoration. Revisions to the forecasted costs of decommissioning activities are made whenever factors indicate that the timing or amounts of estimated cash flows have changed materially. Studies are updated for both nuclear and non-nuclear decommissioning costs at least every five years.  Any accretion or depreciation expense related to these liabilities and assets is charged to a regulatory asset.  See Note 10 — Regulatory Assets and Liabilities — Nuclear Decommissioning Costs and Non-Nuclear Decommissioning Costs and Note 13 —
Asset Retirement Obligations.

Down-blend Offering for Tritium

TVA, the U.S. Department of Energy ("DOE"), and certain nuclear fuel contractors have entered into agreements, referred to as the Down-blend Offering for Tritium ("DBOT"), that provide for the production, processing, and storage of low-enriched uranium that is to be made using surplus DOE highly enriched uranium and other uranium.  Low-enriched uranium can be fabricated into fuel for use in a nuclear power plant.  Production of the low-enriched uranium began in 2019 and is contracted to continue through September 2025. Contract activity will consist of storage and flag management.  Flag management ensures that the uranium is of U.S. origin, free from foreign obligations, and unencumbered by policy restrictions, so that it can be used in connection with the production of tritium. Under the terms of the interagency agreement between the DOE and TVA, the DOE will reimburse TVA for a portion of the costs of converting the highly enriched uranium to low-enriched uranium. Since 2019, TVA has received $188 million in reimbursements from the DOE. At September 30, 2022, TVA recorded $9 million in Accounts receivable, net related to this agreement.

Investment Funds

    Investment funds consist primarily of trust funds designated to fund decommissioning requirements (see Note 21 — Commitments and Contingencies — Decommissioning Costs), the Supplemental Executive Retirement Plan ("SERP") (see Note 20 — Benefit Plans — Overview of Plans and Benefits — Supplemental Executive Retirement Plan), and the Deferred Compensation Plan ("DCP"). The Nuclear Decommissioning Trust ("NDT") holds funds primarily for the ultimate decommissioning of TVA's nuclear power plants. The Asset Retirement Trust ("ART") holds funds primarily for the costs related to the future closure and retirement of TVA's other long-lived assets. The NDT, ART, SERP, and DCP funds are invested in portfolios of securities generally designed to achieve a return in line with overall equity and debt market performance. The NDT, ART, SERP, and DCP funds are all classified as trading.

Insurance

Although TVA uses private companies to administer its healthcare plans for eligible active and retired employees not covered by Medicare, TVA does not purchase health insurance.  Third-party actuarial specialists assist TVA in determining certain liabilities for self-insured claims.  TVA recovers the costs of claims through power rates and through adjustments to the participants' contributions to their benefit plans.  These liabilities are included in Other long-term liabilities on the Consolidated Balance Sheets.

The Federal Employees' Compensation Act ("FECA") governs liability to employees for service-connected injuries.  TVA purchases excess workers' compensation insurance above a self-insured retention.

    In addition to excess workers' compensation insurance, TVA purchases property and liability insurance for nuclear assets and operations. See Note 21 — Commitments and Contingencies — Nuclear Insurance. TVA also purchases liability insurance and property insurance for certain conventional (non-nuclear) assets, and other insurance policies when commercially feasible.

    The insurance policies are subject to the terms and conditions of the specific policy, including deductibles or self-insured retentions. To the extent insurance would not provide either a partial or total recovery of the costs associated with a loss, TVA would have to recover any such costs through other means, including through power rates.

Research and Development Costs

Research and development costs are expensed when incurred.  TVA's research programs include those related to power delivery technologies, emerging technologies (clean energy, renewables, distributed resources, and energy efficiency), technologies related to generation (fossil fuel, nuclear, and hydroelectric), and environmental technologies.

Tax Equivalents

TVA is not subject to federal income taxation. In addition, neither TVA nor its property, franchises, or income is subject to taxation by states or their subdivisions. The TVA Act requires TVA to make payments to states and counties in which TVA conducts its power operations and in which TVA has acquired power properties previously subject to state and local taxation.   The total amount of these payments is five percent of gross revenues from sales of power during the preceding year, excluding sales or deliveries to other federal agencies and off-system sales with other utilities, with a provision for minimum payments under certain circumstances. TVA calculates tax equivalent expense by subtracting the prior year fuel cost-related tax equivalent regulatory asset or liability from the payments made to the states and counties during the current year and adding back the current year fuel cost-related tax equivalent regulatory asset or liability. Fuel cost-related tax equivalent expense is recognized in the same accounting period in which the fuel cost-related revenue is recognized.
Maintenance CostsTVA records maintenance costs and repairs related to its property, plant, and equipment on the Consolidated Statements of Operations as they are incurred except for the recording of certain regulatory assets for retirement and removal costs.
v3.22.2.2
Impact of New Accounting Standards and Interpretations
 12 Months Ended
Sep. 30, 2022
Accounting Changes and Error Corrections [Abstract]  
Accounting Standards Update and Change in Accounting Principle [Text Block] Impact of New Accounting Standards and Interpretations
    The following are accounting standard updates issued by the Financial Accounting Standards Board ("FASB") that TVA adopted during 2022:
Lessor-Certain Leases with Variable Lease Payments
Description
This guidance amends the lessor lease classification for leases that have variable lease payments that are not based on an index or rate. If the lease meets the criteria for classification as either (1) a sale-type or (2) a direct finance lease, and application of the lease guidance would result in recognition of a day-one selling loss, then the lease should be classified as an operating lease.

There are two transition methods provided by the guidance for entities that have adopted the standard:

•Retrospective application to leases that commenced or were modified after the beginning of the period in which the standard was adopted, or
•Prospective application to leases that commence or are modified subsequent to the date that amendments in the guidance are first applied.
Effective Date for TVAOctober 1, 2021
Effect on the Financial Statements or Other Significant MattersTVA adopted this standard on a prospective basis. Adoption of this standard did not have a material
impact on TVA's financial condition, results of operations, or cash flows.
Reference Rate Reform
DescriptionThis guidance provides temporary optional expedients and exceptions to the guidance in GAAP on contract modifications and hedge accounting to ease the financial reporting burdens related to the expected market transition from the London Interbank Offered Rate ("LIBOR") and other interbank offered rates to alternative reference rates, such as the Secured Overnight Financing Rates ("SOFR").
Effective Date for TVADecember 31, 2021
Effect on the Financial Statements or Other Significant Matters
TVA had interest rate swap contracts that totaled a notional value of $1.5 billion at December 31, 2021,
that were indexed to LIBOR. TVA adopted the International Swaps and Derivative Association’s
("ISDA’s") LIBOR fallback protocol for interest rate swaps prior to December 31, 2021. Under this
protocol, U.S. dollar LIBOR transactions would fall back to the SOFR upon cessation of the related
LIBOR publication. The interest rate swap contracts did not receive hedge accounting treatment, and
therefore TVA did not elect any optional expedients for this modification. TVA does not have any other
significant contracts, including lease agreements, that include payments indexed to LIBOR. Therefore,
the change of reference rate did not have a material impact on TVA’s financial condition, results of
operations, or cash flows.

The following accounting standards have been issued but as of September 30, 2022, were not effective and had not been adopted by TVA:

Accounting for Contract Assets and Contract Liabilities from Contracts with Customers
DescriptionThis guidance requires an entity (acquirer) to recognize and measure contract assets and contract
liabilities acquired in a business combination in accordance with revenue with customers. It is
expected that an acquirer will generally recognize and measure acquired contract assets and contract
liabilities in a manner consistent with how the acquiree recognized and measured contract assets and
contract liabilities in the acquiree’s financial statement. The entity should apply the standard prospectively to business combinations occurring on or after the effective date of the standard.
Effective Date for TVAThis new standard is effective for TVA’s interim and annual reporting periods beginning October 1,
2023. While early adoption is permitted, TVA does not currently plan to adopt this standard early.
Effect on the Financial Statements or Other Significant MattersTVA does not expect the adoption of this standard to have a material impact on its financial condition,
results of operations, or cash flows.

Troubled Debt Restructurings and Vintage Disclosures
DescriptionThis guidance eliminates the recognition and measurement guidance on troubled debt restructuring for
creditors that have adopted Financial Instruments-Credit Losses and requires enhanced disclosures
about loan modifications for borrowers experiencing financial difficulty. Additionally, the guidance
requires public business entities to present current-period gross write-offs by year of origination in their
vintage disclosures. The entity should apply the standard prospectively except for the transition method related to the recognition and measurement of troubled debt restructuring. For the transition method, an entity has the option to apply a modified retrospective transition method, resulting in a cumulative-effect adjustment to retained earnings in the period of adoption.
Effective Date for TVAThis new standard is effective for TVA’s interim and annual reporting periods beginning October 1,
2023. While early adoption is permitted, TVA does not currently plan to adopt this standard early.
Effect on the Financial Statements or Other Significant MattersTVA does not expect the adoption of this standard to have a material impact on its financial condition,
results of operations, or cash flows.
v3.22.2.2
Accounts Receivable, Net
 12 Months Ended
Sep. 30, 2022
Accounts Receivable, after Allowance for Credit Loss [Abstract]  
Accounts Receivable, Net
3.  Accounts Receivable, Net

Accounts receivable primarily consist of amounts due from customers for power sales.  The table below summarizes the types and amounts of TVA's accounts receivable:
Accounts Receivable, Net
At September 30
(in millions)
 20222021
Power receivables$1,899 $1,480 
Other receivables108 86 
Accounts receivable, net(1)
$2,007 $1,566 
Note
(1) Allowance for uncollectible accounts was less than $1 million at both September 30, 2022 and 2021, and therefore is not represented in the table above.
v3.22.2.2
Inventories, Net
 12 Months Ended
Sep. 30, 2022
Inventory, Net [Abstract]  
Inventories, Net
4.  Inventories, Net

The table below summarizes the types and amounts of TVA's inventories:
Inventories, Net 
At September 30
(in millions)
 20222021
Materials and supplies inventory$808 $775 
Fuel inventory303 198 
Renewable energy certificates/emissions allowance inventory, net18 12 
Allowance for inventory obsolescence(57)(35)
Inventories, net$1,072 $950 
Fuel inventory increased $105 million at September 30, 2022, as compared to September 30, 2021, primarily due to an increase in coal inventory of $58 million and an increase in natural gas inventory of $32 million. Coal inventory increased primarily due to higher costs of fuel, including transportation costs, as a result of continued supply constraints driven by both domestic and export demand, limited production capacity, and market volatility. Coal inventory also increased over the prior year due to coal conservation efforts and an increase in inventory levels as TVA prepares for winter inventory needs. Natural gas inventory increased primarily due to higher gas prices, as well as an increase in the amount of stored gas to mitigate fuel price volatility.
v3.22.2.2
Net Completed Plant
 12 Months Ended
Sep. 30, 2022
Property, Plant and Equipment, Net, by Type [Abstract]  
Property, Plant, and Equipment and Intangible Assets Net Completed Plant
Net completed plant consisted of the following:
Net Completed Plant
At September 30
(in millions)
 20222021
 CostAccumulated Depreciation 
Net		CostAccumulated DepreciationNet
Coal-fired(1)
$18,145 $13,649 $4,496 $19,319 $14,357 $4,962 
Gas and oil-fired6,112 1,957 4,155 6,076 1,824 4,252 
Nuclear26,629 12,928 13,701 26,024 12,632 13,392 
Transmission8,919 3,301 5,618 8,597 3,215 5,382 
Hydroelectric3,987 1,192 2,795 3,525 1,135 2,390 
Other electrical plant1,724 807 917 1,943 1,103 840 
Multipurpose dams900 396 504 900 388 512 
Other stewardship26 9 17 27 9 18 
Total$66,442 $34,239 $32,203 $66,411 $34,663 $31,748 
Note
(1) TVA recognized accelerated depreciation as a result of the decision to idle or retire certain units and the potential retirement of the remainder of the coal-fired fleet by 2035. See Note 7 — Plant Closures.
v3.22.2.2
Other Long-Term Assets [Text Block]
 12 Months Ended
Sep. 30, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]  
Other Long-Term Assets
9.  Other Long-Term Assets

The table below summarizes the types and amounts of TVA's other long-term assets:
Other Long-Term Assets 
At September 30
(in millions)
 20222021
Loans and other long-term receivables, net$99 $96 
EnergyRight® receivables, net
49 57 
Prepaid long-term service agreements74 44 
Commodity contract derivative assets102 40 
Other70 83 
Total other long-term assets$394 $320 

Loans and Other Long-Term Receivables. TVA's loans and other long-term receivables primarily consist of economic development loans for qualifying organizations and a receivable for reimbursements to recover the cost of providing long-term, on-site storage for spent nuclear fuel. The current and long-term portions of the loans receivable are reported in Accounts
receivable, net and Other long-term assets, respectively, on TVA's Consolidated Balance Sheets. At September 30, 2022 and 2021, the carrying amount of the loans receivable, net of discount, reported in Accounts receivable, net was approximately $6 million and $3 million, respectively.    

EnergyRight® Receivables. In association with the EnergyRight® program, TVA's local power company customers ("LPCs") offer financing to end-use customers for the purchase of energy-efficient equipment. Depending on the nature of the energy-efficiency project, loans may have a maximum term of five years or 10 years. TVA purchases the resulting loans receivable from its LPCs. The loans receivable are then transferred to a third-party bank with which TVA has agreed to repay in full any loans receivable that have been in default for 180 days or more or that TVA has determined are uncollectible. Given this continuing involvement, TVA accounts for the transfer of the loans receivable as secured borrowings. The current and long-term portions of the loans receivable are reported in Accounts receivable, net and Other long-term assets, respectively, on TVA's Consolidated Balance Sheets. At September 30, 2022 and 2021, the carrying amount of the loans receivable, net of discount, reported in Accounts receivable, net was approximately $13 million and $15 million, respectively. See Note 12 — Other Long-Term Liabilities for information regarding the associated financing obligation.

Allowance for Loan Losses. The allowance for loan loss is an estimate of expected credit losses, measured over the estimated life of the loan receivables, that considers reasonable and supportable forecasts of future economic conditions in addition to information about historical experience and current conditions. See Note 1 — Summary of Significant Accounting Policies — Allowance for Uncollectible Accounts.

The allowance components, which consist of a collective allowance and specific loans allowance, are based on the risk characteristics of TVA's loans. Loans that share similar risk characteristics are evaluated on a collective basis in measuring credit losses, while loans that do not share similar risk characteristics with other loans are evaluated on an individual basis.

Allowance Components
At September 30
(in millions)
20222021
EnergyRight® loan reserve
$1 $1 
Economic development loan collective reserve1 1 
Economic development loan specific loan reserve1 2 
Total allowance for loan losses$3 $4 

Prepaid Long-Term Service Agreements. TVA has entered into various long-term service agreements for major
maintenance activities at certain of its combined cycle plants. TVA uses the direct expense method of accounting for these
arrangements. TVA accrues for parts when it takes ownership and for contractor services when they are rendered. Under
certain of these agreements, payments made exceed the value of parts received and services rendered. The current and long-term portions of the resulting prepayments are reported in Other current assets and Other long-term assets, respectively, on
TVA's Consolidated Balance Sheets. At both September 30, 2022 and 2021, prepayments of $12 million were recorded in Other current assets.
Commodity Contract Derivative Assets. TVA enters into certain derivative contracts for natural gas that require physical delivery of the contracted quantity of the commodity. TVA also reinstated the FHP in December 2021, and hedging activity began under the program in the second quarter of 2022. See Note 15 — Risk Management Activities and Derivative Transactions — Derivatives Not Receiving Hedge Accounting Treatment — Commodity Derivatives and — Commodity Derivatives under the FHP for a discussion of TVA's commodity contract derivatives.
v3.22.2.2
Regulatory Assets and Liabilities [Text Block]
 12 Months Ended
Sep. 30, 2022
Regulatory Assets and Liabilities Disclosure [Abstract]  
Regulatory Assets and Liabilities Regulatory Assets and Liabilities
TVA records certain assets and liabilities that result from the regulated ratemaking process that would not be recorded under GAAP for non-regulated entities. As such, certain items that would generally be reported in earnings or that would impact the Consolidated Statements of Operations are recorded as regulatory assets or regulatory liabilities. Regulatory assets generally represent incurred costs that have been deferred because such costs are probable of future recovery in customer rates.  Regulatory liabilities generally represent obligations to make refunds to customers for previous collections for costs that are not likely to be incurred or deferral of gains that will be credited to customers in future periods. Components of regulatory assets and regulatory liabilities are summarized in the table below. 
Regulatory Assets and Liabilities 
At September 30
(in millions)
 20222021
Current regulatory assets  
Unrealized losses on interest rate derivatives$47 $114 
Unrealized losses on commodity derivatives14 3 
Fuel cost adjustment receivable77 79 
Total current regulatory assets138 196 
Non-current regulatory assets  
Retirement benefit plans deferred costs1,839 3,668 
Non-nuclear decommissioning costs2,856 2,653 
Unrealized losses on interest rate derivatives479 1,122 
Nuclear decommissioning costs821 363 
Unrealized losses on commodity derivatives1 — 
Other non-current regulatory assets138 150 
Total non-current regulatory assets6,134 7,956 
Total regulatory assets$6,272 $8,152 
Current regulatory liabilities  
Fuel cost adjustment tax equivalents$218 $130 
Unrealized gains on commodity derivatives173 210 
Total current regulatory liabilities391 340 
Non-current regulatory liabilities  
Retirement benefit plans deferred credits70 — 
Unrealized gains on commodity derivatives102 40 
Total non-current regulatory liabilities172 40 
Total regulatory liabilities$563 $380 

    Retirement Benefit Plans Deferred Costs (Credits).  TVA measures the funded status of its pension and post-retirement ("OPEB") benefit plans at each year-end balance sheet date. The funded status is measured as the difference between the fair value of plan assets and the benefit obligations at the measurement date for each plan. The changes in funded status are actuarial gains and losses that are recognized on TVA's Consolidated Balance Sheets by adjusting the recognized pension and OPEB liabilities, with the offset deferred as a regulatory asset or a regulatory liability. In an unregulated environment, these deferred costs (credits) would be recognized as an increase or decrease to accumulated other comprehensive income (loss) ("AOCI").

    "Incurred cost" is a cost arising from cash paid out or an obligation to pay for an acquired asset or service, and a loss from any cause that has been sustained and for which payment has been or must be made. In the cases of pension and OPEB costs, the unfunded obligation represents a projected liability to the employee for services rendered, and thus it meets the definition of an incurred cost. Therefore, amounts that otherwise would be charged to AOCI for these costs are recorded as a regulatory asset or liability since TVA has historically recovered pension and OPEB expense in rates. Through historical and current year expense included in ratemaking, the TVA Board has demonstrated the ability and intent to include pension and
OPEB costs in allowable costs and in rates for ratemaking purposes. As a result, it is probable that future revenue will result from inclusion of the pension and OPEB regulatory assets or regulatory liability in allowable costs for ratemaking purposes.

    The regulatory asset and liability are classified as long-term, which is consistent with the pension and OPEB liabilities, and are not amortized to the Consolidated Statements of Operations over a specified recovery period. They are adjusted either upward or downward each year in conjunction with the adjustments to the unfunded pension liability and OPEB liability, as calculated by the actuaries. Ultimately the regulatory asset and liability will be recognized in the Consolidated Statements of Operations in the form of pension and OPEB expense as the actuarial liabilities are eliminated in future periods. See Note 20 — Benefit Plans — Obligations and Funded Status.

    Additionally on October 1, 2014, TVA began recognizing pension costs as a regulatory asset to the extent that the amount calculated under GAAP as pension expense differs from the amount TVA contributes to the pension plan. As a result of previous plan design changes, future contributions are expected to exceed the expense calculated under U.S. GAAP. Accordingly, TVA will discontinue this regulatory accounting practice once all such deferred costs have been recovered, at which time it will recognize pension costs in accordance with U.S. GAAP.

Non-Nuclear Decommissioning Costs.  Non-nuclear decommissioning costs include: (1) certain deferred charges related to the future closure and decommissioning of TVA's non-nuclear long-lived assets, (2) recognition of changes in the liability, (3) recognition of changes in the value of TVA's ART, and (4) certain other deferred charges under the accounting rules for AROs.  TVA has established the ART to more effectively segregate, manage, and invest funds to help meet future non-nuclear AROs.  The funds from the ART may be used, among other things, to pay the costs related to the future closure and retirement of non-nuclear long-lived assets under various legal requirements.  These future costs can be funded through a combination of investment funds set aside in the ART, future earnings on those investment funds, and future cash contributions to the ART.  In 2022 and 2021, TVA recovered in rates an amount determined by the average life of debt financed for non-nuclear decommissioning expenditures, assuming a 20-year debt service period, and contributions to the ART. Deferred charges will be recovered in rates based on an analysis of the expected expenditures, contributions, and investment earnings required to recover the decommissioning costs. Recovery of future decommissioning costs is dependent upon the future earnings of the ART, timing of decommissioning activities, and changes in decommissioning estimates. The regulatory asset is classified as long-term as amounts recovered are used to service debt or to contribute to the ART, which is restricted for future decommissioning costs.

Unrealized Losses on Interest Rate Derivatives.  TVA uses regulatory accounting treatment to defer the unrealized gains and losses on certain interest rate derivative contracts. When amounts in these contracts are realized, the resulting gains or losses are included in the ratemaking formula.  The unrealized losses on these interest rate derivatives are recorded on TVA's Consolidated Balance Sheets as current and non-current regulatory assets, and the related realized gains or losses, if any, are recorded on TVA's Consolidated Statements of Operations when the contracts settle. A portion of certain unrealized gains and losses will be amortized into earnings over the remaining lives of the contracts. Gains and losses on interest rate derivatives that are expected to be realized within the next year are included as a current regulatory asset or liability on TVA's Consolidated Balance Sheet.

Due to rising interest rates in the financial markets and net settlement payments made during 2022, TVA experienced a reduction in unrealized losses related to its derivative instruments for the year ended September 30, 2022. TVA does not recognize unrealized gains and losses from the investment portfolios and derivative instruments within earnings but rather defers all such gains and losses within a regulatory liability or asset in accordance with its accounting policy. See Note 15 — Risk Management Activities and Derivative Transactions and Note 16 — Fair Value Measurements.

Nuclear Decommissioning Costs.  Nuclear decommissioning costs include: (1) certain deferred charges related to the future closure and decommissioning of TVA's nuclear generating units under the Nuclear Regulatory Commission ("NRC") requirements, (2) recognition of changes in the liability, (3) recognition of changes in the value of TVA's NDT, and (4) certain other deferred charges under the accounting rules for AROs.  These future costs can be funded through a combination of investment funds set aside in the NDT and ART and future earnings on those investment funds. Deferred charges will be recovered in rates based on the analysis of expected expenditures, contributions, and investment earnings required to recover the decommissioning costs.  See Note 1 — Summary of Significant Accounting Policies — Investment Funds.  Recovery of future decommissioning costs is dependent upon the future earnings of the NDT and ART, timing of decommissioning activities, and changes in decommissioning estimates. The regulatory asset is classified as long-term as amounts recovered are contributed to the NDT or the ART, which are restricted for future decommissioning costs.

Nuclear decommissioning costs increased $458 million for the year ended September 30, 2022 as compared to the same period of the prior year, primarily due to investment losses in the NDT and accretion of the related AROs. See Note 13 — Asset Retirement Obligations and Note 16 — Fair Value Measurements

Unrealized Gains (Losses) on Commodity Derivatives.  TVA enters into certain derivative contracts for natural gas that require the physical delivery of the contracted quantity of the commodity. Unrealized gains (losses) on natural gas purchase contracts, included as part of unrealized gains (losses) on commodity derivatives, relate to the mark-to-market ("MtM") valuation of natural gas purchase contracts.  The natural gas purchase contracts qualify as derivative contracts but do not qualify for cash
flow hedge accounting treatment.  As a result, TVA recognizes the changes in the market value of these derivative contracts as a regulatory liability or asset.  This treatment reflects TVA's ability and intent to recover the cost of these commodity contracts on a settlement basis for ratemaking purposes through the fuel cost adjustment. TVA recognizes the actual cost of fuel received under these contracts in fuel expense at the time the fuel is used to generate electricity.  These contracts expire at various times through October 2024.  Unrealized gains and losses on contracts with a maturity of less than one year are included as a current regulatory asset or liability on TVA's Consolidated Balance Sheets.  See Note 15 — Risk Management Activities and Derivative Transactions.

TVA reinstated the FHP in December 2021, and hedging activity began under the program in the second quarter of 2022. Currently, TVA is hedging exposure to the price of natural gas under the FHP. Deferred gains and losses relating to TVA's FHP are included as part of unrealized gains and losses on commodity derivatives. TVA defers all MtM unrealized gains or losses as regulatory liabilities or assets, respectively, and records the realized gains or losses in fuel and purchased power expense as the contracts settle to match the delivery period of the underlying commodity. This accounting treatment reflects TVA's ability and intent to include the realized gains or losses of these commodity contracts in future periods through the fuel cost adjustment. Net unrealized gains and losses for any settlements that occur within 12 months or less are classified as a current regulatory liability or asset. See Note 15 — Risk Management Activities and Derivative Transactions.

Fuel Cost Adjustment Receivable.  The fuel cost adjustment provides a mechanism to alter rates monthly to reflect changing fuel and purchased power costs. There is typically a lag between the occurrence of a change in fuel and purchased power costs and the reflection of the change in fuel rates.  Balances in the fuel cost adjustment regulatory accounts represent over-collected or under-collected revenues that offset fuel and purchased power costs, and the fuel rate is designed to recover or refund the balance in less than one year.

Other Non-Current Regulatory Assets. Other non-current regulatory assets consist of the following:

    Deferred Lease Asset and Other Financing Obligations. For certain leases, TVA recognized the initial finance lease and other financing asset and liability at inception of the lease or other obligation. However, the annual expense recognized in rates is equal to the annual payments, which differs from GAAP treatment for non-regulated entities. This practice results in TVA's asset balances being higher than they otherwise would have been under GAAP, with the difference representing a regulatory asset related to the lease or other financing obligation. These costs will be amortized over the respective lease or other financing obligation terms as payments are made. As the costs associated with this regulatory asset are not currently being considered in rates and the asset is expected to increase over the next year, the regulatory asset has been classified as long-term.

Debt Reacquisition Costs.  Reacquisition expenses, call premiums, and other related costs, such as unamortized debt issue costs associated with redeemed Bond issues, are deferred and amortized (accreted) on a straight-line basis over the weighted average life of TVA's debt portfolio. Because timing of additional reacquisition expenses and changes to the weighted average life of the debt are uncertain, the regulatory asset is classified as long-term.

Retirement Removal Costs.  Retirement removal costs, net of salvage, that are not legally required are recognized as a regulatory asset. Net removal costs are amortized over a one-year period subsequent to completion of the removal activities. TVA treats this regulatory asset as long-term in its entirety primarily because it relates to assets that are long-term in nature.
Fuel Cost Adjustment Tax Equivalents.  The fuel cost adjustment includes a provision related to the current funding of the future payments TVA will make.  As TVA records the fuel cost adjustment, five percent of the calculation that relates to a future asset or liability for tax equivalent payments is recorded as a current regulatory liability and paid or refunded in the following year.
v3.22.2.2
Variable Interest Entities (Text Block)
 12 Months Ended
Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Variable Interest Entities
11.  Variable Interest Entities

A VIE is an entity that either (i) has insufficient equity to permit the entity to finance its activities without additional subordinated financial support or (ii) has equity investors who lack the characteristics of owning a controlling financial interest. When TVA determines that it has a variable interest in a VIE, a qualitative evaluation is performed to assess which interest holders have the power to direct the activities that most significantly impact the economic performance of the entity and have the obligation to absorb losses or receive benefits that could be significant to the entity. The evaluation considers the purpose and design of the business, the risks that the business was designed to create and pass along to other entities, the activities of the business that can be directed and which party can direct them, and the expected relative impact of those activities on the economic performance of the business through its life. TVA has the power to direct the activities of an entity when it has the ability to make key operating and financing decisions, including, but not limited to, capital investment and the issuance of debt. Based on the evaluation of these criteria, TVA has determined it is the primary beneficiary of certain entities and as such is required to account for the VIEs on a consolidated basis.

John Sevier VIEs

In 2012, TVA entered into a $1.0 billion construction management agreement and lease financing arrangement with
John Sevier Combined Cycle Generation LLC ("JSCCG") for the completion and lease by TVA of the John Sevier Combined Cycle Facility ("John Sevier CCF"). JSCCG is a special single-purpose limited liability company formed in January 2012 to finance the John Sevier CCF through a $900 million secured note issuance (the "JSCCG notes") and the issuance of $100 million of membership interests subject to mandatory redemption.  The membership interests were purchased by John Sevier Holdco LLC ("Holdco").  Holdco is a special single-purpose entity, also formed in January 2012, established to acquire and hold the membership interests in JSCCG.  A non-controlling interest in Holdco is held by a third-party through nominal membership interests, to which none of the income, expenses, and cash flows are allocated. 
 
The membership interests held by Holdco in JSCCG were purchased with proceeds from the issuance of $100 million of secured notes (the "Holdco notes") and are subject to mandatory redemption pursuant to a schedule of amortizing, semi-annual payments due each January 15 and July 15, with a final payment due in January 2042. The payment dates for the mandatorily redeemable membership interests are the same as those of the Holdco notes. The sale of the JSCCG notes, the membership interests in JSCCG, and the Holdco notes closed in January 2012. The JSCCG notes are secured by TVA's lease payments, and the Holdco notes are secured by Holdco's investment in, and amounts receivable from, JSCCG. TVA's lease payments to JSCCG are equal to and payable on the same dates as JSCCG's and Holdco's semi-annual debt service payments. In addition to the lease payments, TVA pays administrative and miscellaneous expenses incurred by JSCCG and Holdco. Certain agreements related to this transaction contain default and acceleration provisions.

    Due to its participation in the design, business activity, and credit and financial support of JSCCG and Holdco, TVA
has determined that it has a variable interest in each of these entities. Based on its analysis, TVA has concluded that it is the
primary beneficiary of JSCCG and Holdco and, as such, is required to account for the VIEs on a consolidated basis. Holdco's
membership interests in JSCCG are eliminated in consolidation.

Southaven VIE

        In 2013, TVA entered into a $400 million lease financing arrangement with Southaven Combined Cycle Generation LLC ("SCCG") for the lease by TVA of the Southaven Combined Cycle Facility ("Southaven CCF"). SCCG is a special single-purpose limited liability company formed in June 2013 to finance the Southaven CCF through a $360 million secured notes issuance (the "SCCG notes") and the issuance of $40 million of membership interests subject to mandatory redemption. The membership interests were purchased by Southaven Holdco LLC ("SHLLC"). SHLLC is a special single-purpose entity, also formed in June 2013, established to acquire and hold the membership interests in SCCG. A non-controlling interest in SHLLC is held by a third-party through nominal membership interests, to which none of the income, expenses, and cash flows of SHLLC are allocated.

The membership interests held by SHLLC were purchased with proceeds from the issuance of $40 million of secured notes (the "SHLLC notes") and are subject to mandatory redemption pursuant to a schedule of amortizing, semi-annual payments due each February 15 and August 15, with a final payment due on August 15, 2033. The payment dates for the mandatorily redeemable membership interests are the same as those of the SHLLC notes, and the payment amounts are sufficient to provide returns on, as well as returns of, capital until the investment has been repaid to SHLLC in full. The rate of return on investment to SHLLC is 7.0 percent, which is reflected as interest expense in the Consolidated Statements of Operations. SHLLC is required to pay a pre-determined portion of the return on investment to Seven States Southaven, LLC ("SSSL") on each lease payment date as agreed in SHLLC's formation documents (the "Seven States Return"). The current and long-term portions of the Membership interests of VIE subject to mandatory redemption are included in Accounts payable and accrued liabilities and Other long-term liabilities, respectively.

The payment dates for the mandatorily redeemable membership interests are the same as those of the SHLLC notes. The SCCG notes are secured by TVA's lease payments, and the SHLLC notes are secured by SHLLC's investment in, and amounts receivable from, SCCG. TVA's lease payments to SCCG are payable on the same dates as SCCG's and SHLLC's semi-annual debt service payments and are equal to the sum of (i) the amount of SCCG's semi-annual debt service payments, (ii) the amount of SHLLC's semi-annual debt service payments, and (iii) the amount of the Seven States Return. In addition to the lease payments, TVA pays administrative and miscellaneous expenses incurred by SCCG and SHLLC. Certain agreements related to this transaction contain default and acceleration provisions.

    In the event that TVA were to choose to exercise an early buy out feature of the Southaven facility lease, in part or in whole, TVA must pay to SCCG amounts sufficient for SCCG to repay or partially repay on a pro rata basis the membership interests held by SHLLC, including any outstanding investment amount plus accrued but unpaid return. TVA also has the right, at any time and without any early redemption of the other portions of the Southaven facility lease payments due to SCCG, to fully repay SHLLC's investment, upon which repayment SHLLC will transfer the membership interests to a designee of TVA.

    TVA participated in the design, business activity, and financial support of SCCG and has determined that it has a direct variable interest in SCCG resulting from risk associated with the value of the Southaven CCF at the end of the lease term. Based on its analysis, TVA has determined that it is the primary beneficiary of SCCG and, as such, is required to account for the VIE on a consolidated basis.
Impact on Consolidated Financial Statements

    The financial statement items attributable to carrying amounts and classifications of JSCCG, Holdco, and SCCG as of September 30, 2022 and 2021, as reflected on the Consolidated Balance Sheets, are as follows:
Summary of Impact of VIEs on Consolidated Balance Sheets
At September 30
(in millions)
 20222021
Current liabilities 
Accrued interest$10 $10 
Accounts payable and accrued liabilities2 3 
Current maturities of long-term debt of variable interest entities39 43 
Total current liabilities
51 56 
Other liabilities
Other long-term liabilities18 20 
Long-term debt, net
Long-term debt of variable interest entities, net968 1,006 
Total liabilities$1,037 $1,082 

Interest expense of $50 million, $52 million, and $54 million related to debt of VIEs and membership interests of variable interest entity subject to mandatory redemption is included on the Consolidated Statements of Operations for the years ended September 30, 2022, 2021, and 2020, respectively.

At September 30, 2022, TVA had outstanding debt of VIEs of $1.0 billion and outstanding membership interests subject to mandatory redemption (including current portion) of $20 million issued by one of its VIEs of which it is the primary beneficiary. The following table sets forth TVA's future payments at September 30, 2022:
Maturities Due in the Year Ending September 30
(in millions)
 20232024202520262027Thereafter
Long-term debt of VIEs including current maturities(1)
$39 $36 $37 $39 $40 $822 
Membership interests of variable interest entity subject to mandatory redemption2 1 1 1 1 14 
Note
(1) Long-term debt of VIEs does not include non-cash item of unamortized debt issue costs of $6 million.

Creditors of the VIEs do not have any recourse to the general credit of TVA. TVA does not have any obligations to provide financial support to the VIEs other than as prescribed in the terms of the agreements related to these transactions.
v3.22.2.2
Asset Retirement Obligations
 12 Months Ended
Sep. 30, 2022
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligations Asset Retirement Obligations
    During the year ended September 30, 2022, TVA's total ARO liability increased $160 million.

    To estimate its decommissioning obligation related to its nuclear generating stations, TVA uses a probability-weighted, discounted cash flow model which, on a unit-by-unit basis, considers multiple outcome scenarios that include significant estimations and assumptions. Those assumptions include (1) estimates of the cost of decommissioning; (2) the method of decommissioning and the timing of the related cash flows; (3) the license period of the nuclear plant, considering the probability of license extensions; (4) cost escalation factors; and (5) the credit adjusted risk free rate to measure the obligation at the present value of the future estimated costs. TVA has ascribed probabilities to two different decommissioning methods related to its nuclear decommissioning obligation estimate: the DECON method and the SAFSTOR method. The DECON method requires radioactive contamination to be removed from a site and safely disposed of or decontaminated to a level that permits the site to be released for unrestricted use shortly after it ceases operation. The SAFSTOR method allows nuclear facilities to be placed and maintained in a condition that allows the facilities to be safely stored and subsequently decontaminated to levels that permit release for unrestricted use.

    The revisions in nuclear estimates increased the liability balance by $61 million for the year ended September 30, 2022. This was primarily due to approval and implementation of the most recent site-specific cost study in September 2022 resulting in an increase of $58 million.

    TVA also has decommissioning obligations related to its non-nuclear generating sites, ash impoundments, transmission substation and distribution assets, and certain general facilities. To estimate its decommissioning obligation related to these assets, TVA uses estimations and assumptions for the amounts and timing of future expenditures and makes judgments concerning whether or not such costs are considered a legal obligation. Those assumptions include (1) estimates of the costs of decommissioning, (2) the method of decommissioning and the timing of the related cash flows, (3) the expected retirement date of each asset, (4) cost escalation factors, and (5) the credit adjusted risk free rate to measure the obligation at the present value of the future estimated costs. TVA bases its decommissioning estimates for each asset on its identified preferred closure method.

The revisions in non-nuclear estimates increased the liability balance by $186 million for the year ended September 30, 2022. During the year, TVA completed an engineering review of its cost estimates for closure of certain areas containing coal fines at Paradise Fossil Plant ("Paradise"), which resulted in an increase of $119 million due to expected cost increases for necessary changes in activities associated with proper completion of the closure. Coal combustion residuals ("CCR") closure liabilities at Paradise and Cumberland increased $82 million due to new vendor bids, modified closure designs, and revised estimates for construction costs. Refined project cost assumptions and scope changes related to TVA's AROs for the closure of certain coal yards at its fossil plants resulted in an increase of $57 million. In addition, effective October 1, 2022, TVA implemented revised depreciation rates applicable to its completed plant due to the results of a new depreciation study. The study included a decline in the service life estimates of TVA's coal-fired plants based on current planning assumptions to potentially retire the remainder of the coal-fired fleet by 2035. As a result of the change in service life estimates reflected in the depreciation study, TVA performed an assessment of the assumptions used in the timing of cash flows related to its non-nuclear AROs. Based on the assessment, TVA increased AROs by $47 million due to identified changes in the projections of timing of certain asset retirement activities. Partially offsetting these increases, expected reductions in CCR post-closure costs for maintenance and monitoring at Paradise, Shawnee, and Colbert Fossil Plant ("Colbert") resulted in a decrease of $53 million. CCR closure liabilities at Gallatin decreased $30 million due to selection of a new vendor bid and changes to anticipated timing
of certain asset retirement activities. In addition, CCR closure liabilities at Allen Fossil Plant decreased $15 million as a result of changes in cost estimates and anticipated timing of various retirement activities.

    The revisions in non-nuclear estimates increased $191 million for the year ended September 30, 2021. This increase was primarily driven by revisions of approximately $122 million to certain CCR closure liabilities at Shawnee, Paradise, Colbert, Cumberland, and Gallatin resulting from revised engineering estimates for construction costs, new vendor bids, modified closure designs, and expected costs associated with post-closure care of closed areas. CCR ARO liabilities associated with groundwater well monitoring also increased approximately $69 million due to expansion in the scope of recurring activities including measuring, modeling, and reporting. In addition, TVA's use of a new CCR landfill at Shawnee and expansion of landfill acreage used at Gallatin resulted in new obligations of $30 million and $13 million, respectively.
    
    Additionally, during the years ended September 30, 2022 and 2021, both the nuclear and non-nuclear liabilities were increased by periodic accretion, partially offset by settlement projects that were conducted during these periods. The nuclear and non-nuclear accretion amounts were deferred as regulatory assets. During 2022, 2021, and 2020, $137 million, $72 million, and $169 million, respectively, of the related regulatory assets were amortized into expense as these amounts were collected in rates. See Note 10 — Regulatory Assets and Liabilities. TVA maintains investment trusts to help fund its decommissioning obligations. See Note 16 — Fair Value Measurements — Investment Funds and Note 21 — Commitments and Contingencies — Decommissioning Costs for a discussion of the trusts' objectives and the current balances of the trusts.
Asset Retirement Obligation Activity
(in millions)
 NuclearNon-NuclearTotal
Balance at September 30, 2020$3,278 $3,507 $6,785 
Settlements(11)(231)(242)
Revisions in estimate12 191 203 
Additional obligations— 43 43 
Accretion (recorded as regulatory asset)149 64 213 
Balance at September 30, 20213,428 3,574 7,002 
(1)
Settlements(2)(309)(311)
(2)
Revisions in estimate61 186 247 
Accretion (recorded as regulatory asset)156 68 224 
Balance at September 30, 2022$3,643 $3,519 $7,162 
(1)
Note
(1) Includes $275 million and $266 million at September 30, 2022 and 2021, respectively, in Current liabilities.
(2) Settlements include the change in asset retirement obligation project accruals included in Accounts payable and accrued liabilities of $20 million.
v3.22.2.2
Other Long-Term Liabilities
 12 Months Ended
Sep. 30, 2022
Other Liabilities, Noncurrent [Abstract]  
Other Long-Term Liabilities Other Long-Term Liabilities
Other long-term liabilities consist primarily of liabilities related to certain derivative agreements as well as liabilities related to operating leases. The table below summarizes the types and amounts of Other long-term liabilities:
Other Long-Term Liabilities
At September 30
(in millions)
 2022
2021(1)
Interest rate swap liabilities$851 $1,524 
Operating lease liabilities93 122 
Currency swap liabilities228 76 
EnergyRight® financing obligation58 66 
Long-term deferred compensation39 42 
Advances for construction53 24 
Long-term deferred revenue39 37 
Accrued long-term service agreements— 29 
Other124 121 
Total other long-term liabilities$1,485 $2,041 
Note
(1) At September 30, 2021, $5 million and $19 million previously classified as Long-term deferred revenue (a component of Other long-term liabilities) and Other (a
component of Other long-term liabilities), respectively, were reclassified to Advances for construction (a component of Other long-term liabilities) to conform
with current year presentation.
Interest Rate Swap Liabilities. TVA uses interest rate swaps to fix variable short-term debt to a fixed rate. The values of these derivatives are included in Accounts payable and accrued liabilities, Accrued interest, and Other long-term liabilities on the Consolidated Balance Sheets. At September 30, 2022 and 2021, the carrying amount of the interest rate swap liabilities reported in Accounts payable and accrued liabilities and Accrued interest was $54 million and $115 million, respectively. See Note 15 — Risk Management Activities and Derivative Transactions — Derivatives Not Receiving Hedge Accounting Treatment — Interest Rate Derivatives for information regarding the interest rate swap liabilities. As of September 30, 2022, interest rate swap liabilities (including current portion) decreased $734 million as compared to September 30, 2021, primarily due to increases in market interest rates along with net settlement payments made during the year.

Operating Lease Liabilities. TVA's operating leases consist primarily of railcars, equipment, real estate/land, and power generating facilities. At September 30, 2022 and 2021, the current portion of TVA's operating leases reported in Accounts payable and accrued liabilities was $59 million and $40 million, respectively. See Note 8 — Leases for more information regarding leases.

Currency Swap Liabilities. To protect against exchange rate risk related to British pound sterling denominated Bond transactions, TVA entered into foreign currency hedges. The values of these derivatives are included in Accounts payable and accrued liabilities and Other long-term liabilities on the Consolidated Balance Sheets. At September 30, 2022 and 2021, the carrying amount of the currency swap liabilities reported in Accounts payable and accrued liabilities was $12 million and $7 million, respectively. As of September 30, 2022, currency swap liabilities (including current portion) increased $157 million as compared to September 30, 2021, primarily due to the strengthening of the U.S. dollar against the British pound sterling. See Note 15 — Risk Management Activities and Derivative Transactions — Cash Flow Hedging Strategy for Currency Swaps for more information regarding the currency swap liabilities.

    EnergyRight® Financing Obligation. TVA purchases certain loans receivable from its LPCs in association with the EnergyRight® program. The current and long-term portions of the resulting financing obligation are reported in Accounts payable and accrued liabilities and Other long-term liabilities, respectively, on TVA's Consolidated Balance Sheets. At September 30, 2022 and 2021, the carrying amount of the financing obligation reported in Accounts payable and accrued liabilities was $14 million and $16 million, respectively. See Note 9 — Other Long-Term Assets for information regarding the associated loans receivable.

Long-Term Deferred Compensation. TVA provides compensation arrangements to engage and retain certain employees, both executive and non-executive, which are designed to provide participants with the ability to defer compensation to future periods. The current and long-term portions are recorded in Accounts payable and accrued liabilities and Other long-term liabilities, respectively, on TVA’s Consolidated Balance Sheets. At September 30, 2022 and 2021, the current amount of deferred compensation recorded in Accounts payable and accrued liabilities was $53 million and $51 million, respectively.

Advances for Construction. TVA receives refundable and non-refundable advances for construction that are generally intended to defray all or a portion of the costs of building or extending TVA’s existing power assets. Amounts received are
deferred as a liability with the long-term portion representing amounts that will not be recognized within the next 12 months. As projects meet milestones or other contractual obligations, the refundable portion is refunded to the customer and the non-refundable portion is recognized as contributions in aid of construction and offsets the cost of plant assets. At September 30, 2022 and 2021, the current amount of advances for construction recorded in Accounts payable and accrued liabilities was $33 million and $38 million, respectively.

Long-Term Deferred Revenue. Long-term deferred revenue represents payments received that exceed services rendered resulting in the deferral of revenue. This long-term portion represents amounts that will not be recognized within the next 12 months primarily related to fiber and transmission agreements. The current and long-term portions of the deferral are recorded in Accounts payable and accrued liabilities and Other long-term liabilities, respectively, on TVA’s Consolidated Balance Sheets. At September 30, 2022 and 2021, the current amount of deferred revenue recorded in Accounts payable and accrued liabilities was $16 million and $17 million, respectively.

    Accrued Long-Term Service Agreements. TVA has entered into various long-term service agreements for major
maintenance activities at certain of its combined cycle plants. TVA uses the direct expense method of accounting for these
arrangements. TVA accrues for parts when it takes ownership and for contractor services when they are rendered. Under
certain of these agreements, parts received and services rendered exceed payments made. The current and long-term portions
of the resulting obligation are recorded in Accounts payable and accrued liabilities and Other long-term liabilities, respectively, on
TVA's Consolidated Balance Sheets. At September 30, 2022 and 2021, the current amount of accrued long-term service agreements recorded in Accounts payable and accrued liabilities was $32 million and $28 million, respectively.
v3.22.2.2
Debt and Other Obligations
 12 Months Ended
Sep. 30, 2022
Debt Disclosure [Abstract]  
Debt and Other Obligations Debt and Other Obligations
General

The TVA Act authorizes TVA to issue Bonds in an amount not to exceed $30.0 billion at any time.  At September 30, 2022, TVA had only two types of Bonds outstanding: power bonds and discount notes.  Power bonds have maturities between one year and 50 years, and discount notes have maturities of less than one year.  Power bonds and discount notes are both issued pursuant to Section 15d of the TVA Act and pursuant to the Basic Tennessee Valley Authority Power Bond Resolution adopted by the TVA Board on October 6, 1960, as amended on September 28, 1976, October 17, 1989, and March 25, 1992 (the "Basic Resolution").  Bonds are not obligations of the U.S., and the U.S. does not guarantee the payments of principal or interest on Bonds.

Power bonds and discount notes rank on parity and have first priority of payment from net power proceeds, which are defined as the remainder of TVA's gross power revenues after deducting the costs of operating, maintaining, and administering its power properties and tax equivalent payments, but before deducting depreciation accruals or other charges representing the amortization of capital expenditures, plus the net proceeds from the sale or other disposition of any power facility or interest therein.

TVA considers its scheduled rent payments under its leaseback transactions, as well as its scheduled payments under its lease financing arrangements involving John Sevier CCF and Southaven CCF, as costs of operating, maintaining, and administering its power properties. Costs of operating, maintaining, and administering TVA's power properties have priority over TVA's payments on the Bonds.  Once net power proceeds have been applied to payments on power bonds and discount notes as well as any other Bonds that TVA may issue in the future that rank on parity with or subordinate to power bonds and discount notes, Section 2.3 of the Basic Resolution provides that the remaining net power proceeds shall be used only for (1) minimum payments into the U.S. Treasury required by the TVA Act as repayment of, and as a return on, the Power Program Appropriation
Investment; (2) investment in power system assets; (3) additional reductions of TVA's capital obligations; and (4) other lawful purposes related to TVA's power business.

The TVA Act and the Basic Resolution each contain two bond tests: the rate test and the bondholder protection test.  Under the rate test, TVA must charge rates for power which will produce gross revenues sufficient to provide funds for, among other things, debt service on outstanding Bonds.  As of September 30, 2022, TVA was in compliance with the rate test. See Note 1 — Summary of Significant Accounting Policies — General.  Under the bondholder protection test, TVA must, in successive five-year periods, use an amount of net power proceeds at least equal to the sum of (1) the depreciation accruals and other charges representing the amortization of capital expenditures and (2) the net proceeds from any disposition of power facilities for either the reduction of its capital obligations (including Bonds and the Power Program Appropriation Investment) or investment in power assets. TVA met the bondholder protection test for the five-year period ended September 30, 2020, and must next meet the bondholder protection test for the five-year period ending September 30, 2025.

Secured Debt of VIEs

On August 9, 2013, SCCG issued secured notes totaling $360 million that bear interest at a rate of 3.846 percent. The SCCG notes require amortizing semi-annual payments on each February 15 and August 15, and mature on August 15, 2033. Also on August 9, 2013, SCCG issued $40 million of membership interests subject to mandatory redemption. The proceeds from the secured notes issuance and the issuance of the membership interests were paid to TVA in accordance with the terms of the Southaven head lease. See Note 11 — Variable Interest Entities — Southaven VIE. TVA used the proceeds from the transaction primarily to fund the acquisition of the Southaven CCF from SSSL.

On January 17, 2012, JSCCG issued secured notes totaling $900 million in aggregate principal amount that bear interest at a rate of 4.626 percent. Also on January 17, 2012, Holdco issued secured notes totaling $100 million that bear interest at a rate of 7.1 percent. The JSCCG notes and the Holdco notes require amortizing semi-annual payments on each January 15 and July 15, and mature on January 15, 2042. The Holdco notes require a $10 million balloon payment upon maturity. See Note 11 — Variable Interest Entities — John Sevier VIEs. TVA used the proceeds from the transaction to meet its requirements under the TVA Act.

Secured debt of VIEs, including current maturities, outstanding at both September 30, 2022 and 2021 totaled $1.0 billion.

Short-Term Debt

    The following table provides information regarding TVA's short-term borrowings:
Short-term Borrowings
At September 30
 20222021
Gross amount outstanding - discount notes (in millions)$1,173 $780 
Weighted average interest rate - discount notes2.93 %0.03 %

Put Options

TVA has two issues of Putable Automatic Rate Reset Securities ("PARRS") outstanding.  After a fixed-rate period of five years, the coupon rate on the PARRS may automatically be reset downward under certain market conditions on an annual basis.  The coupon rate reset on the PARRS is based on a calculation.  For both series of PARRS, the coupon rate will reset downward on the reset date if the rate calculated is below the then-current coupon rate on the Bond.  The calculation dates, potential reset dates, and terms of the calculation are different for each series.  The coupon rate on the 1998 Series D PARRS may be reset on June 1 (annually) if the sum of the five-day average of the 30-Year Constant Maturity Treasury ("CMT") rate for the week ending the last Friday in April, plus 94 basis points, is below the then-current coupon rate.  The coupon rate on the 1999 Series A PARRS may be reset on May 1 (annually) if the sum of the five-day average of the 30-Year CMT rate for the week ending the last Friday in March, plus 84 basis points, is below the then-current coupon rate.  The coupon rates may only be reset downward, but investors may request to redeem their Bonds at par value in conjunction with a coupon rate reset for a limited period of time prior to the reset dates under certain circumstances.

The coupon rate for the 1998 Series D PARRS, which mature in June 2028, has been reset eight times, from an initial rate of 6.750 percent to the current rate of 2.134 percent.  In connection with these resets, $318 million of the Bonds have been redeemed; therefore, $256 million of the Bonds were outstanding at September 30, 2022.  The coupon rate for the 1999 Series A PARRS, which mature in May 2029, has been reset seven times, from an initial rate of 6.50 percent to the current rate of 2.216 percent.  In connection with these resets, $316 million of the Bonds have been redeemed; therefore, $208 million of the Bonds were outstanding at September 30, 2022.
Due to the contingent nature of the put option on the PARRS, TVA determines whether the PARRS should be classified as long-term debt or current maturities of long-term debt by calculating the expected reset rate for the Bonds on the calculation dates, described above.  If the determination date for reset is before the balance sheet date of the reporting period and the expected reset rate is less than the then-current coupon rate on the PARRS, the PARRS are included in current maturities. Otherwise, the PARRS are included in long-term debt.  

Debt Securities Activity

The table below summarizes the long-term debt securities activity for the years ended September 30, 2022 and 2021.
Debt Securities Activity
For the years ended September 30
(in millions)
 20222021
Issues
2021 Series A(1)
$— $500 
2022 Series A(2)
500 — 
Discount on debt issues(16)— 
Total$484 $500 
Redemptions/Maturities(3)
 
2009 Series B$28 $29 
2011 Series A— 1,500 
1998 Series H— 331 
2012 Series A1,000 — 
Total redemptions/maturities of power bonds1,028 1,860 
Debt of variable interest entities43 41 
Total redemptions/maturities of debt$1,071 $1,901 
Notes
(1) The 2021 Series A Bonds were issued at 99.982 percent of par.
(2) The 2022 Series A Bonds were issued at 96.786 percent of par.
(3) All redemptions were at 100 percent of par.

Debt Outstanding

    Total debt outstanding at September 30, 2022 and 2021, consisted of the following: 
Short-Term Debt
At September 30
(in millions)
 
CUSIP or Other Identifier
 
Maturity
 
Coupon Rate		20222021
Short-term debt, net of discounts$1,172 $780 
Current maturities of long-term debt of VIEs issued at par39 43 
Current maturities of power bonds issued at par
880591EN88/15/20221.875%— 1,000 
880591EF512/15/20223.770%1 1 
880591EF56/15/20233.770%28 27 
Total current maturities of power bonds issued at par  29 1,028 
Total current debt outstanding, net  $1,240 $1,851 
Long-Term Debt
At September 30
(in millions)
 
CUSIP or Other Identifier
 
Maturity
Coupon
Rate		2022 Par2021 ParStock Exchange Listings
880591ER99/15/20242.875%$1,000 $1,000 New York
880591EW85/15/20250.750%1,000 1,000 New York
880591CJ911/1/20256.750%1,350 1,350 New York, Hong Kong, Luxembourg, Singapore
880591EU22/1/20272.875%1,000 1,000 New York
880591300(3)
6/1/20282.134%256 256 New York
880591409(3)
5/1/20292.216%208 208 New York
880591DM15/1/20307.125%1,000 1,000 New York, Luxembourg
880591EX69/15/20311.500%500 500 New York
880591DP46/7/20326.587%
(2)
279 
(1)
337 
(1)
New York, Luxembourg
880591DV17/15/20334.700%472 472 New York, Luxembourg
880591EF56/15/20343.770%160 190 None
880591DX76/15/20354.650%436 436 New York
880591CK64/1/20365.980%121 121 New York
880591CS94/1/20365.880%1,500 1,500 New York
880591CP51/15/20386.150%1,000 1,000 New York
880591ED06/15/20385.500%500 500 New York
880591EH19/15/20395.250%2,000 2,000 New York
880591EP312/15/20423.500%1,000 1,000 New York
880591DU36/7/20434.962%
(2)
168 
(1)
202 
(1)
New York, Luxembourg
880591EB41/15/20484.875%500 500 New York, Luxembourg
880591DZ24/1/20565.375%1,000 1,000 New York
880591EJ79/15/20604.625%1,000 1,000 New York
880591ES79/15/20654.250%1,000 1,000 New York
880591EY49/15/20524.250%500 — New York
Subtotal17,950 17,572  
Unamortized discounts, premiums, issue costs, and other (124)(115) 
Total long-term outstanding power bonds, net 17,826 17,457  
Long-term debt of VIEs, net968 1,006 
Total long-term debt, net$18,794 $18,463 
Notes
(1)  Includes net exchange gain from currency transactions of $150 million and $58 million at September 30, 2022 and 2021, respectively.
(2)  The coupon rate represents TVA's effective interest rate.
(3)  TVA PARRS, CUSIP numbers 880591300 and 880591409, may be redeemed under certain conditions.  See Put Options above.

 
Maturities Due in the Year Ending September 30
(in millions)
 20232024202520262027ThereafterTotal
Long-term power bonds including current maturities(1)
$29 $1,022 $1,022 $1,370 $1,020 $13,666 $18,129 
Short-term debt(2)
1,173 — — — — — 1,173 
Notes
(1) Long-term power bonds does not include non-cash items of foreign currency exchange gain of $150 million, unamortized debt issue costs of $42 million, and net
discount on sale of Bonds of $82 million.
(2) Short-term debt does not include the non-cash item of discount on issuance of discount notes of $1 million.

Credit Facility Agreements

TVA has funding available under four long-term revolving credit facilities totaling approximately $2.7 billion: a $150 million credit facility that matures on February 9, 2024, a $500 million credit facility that matures on February 1, 2025, a $1.0 billion credit facility that matures on September 21, 2026, and a $1.0 billion credit facility that matures on March 25, 2027. The interest rate on any borrowing under these facilities varies based on market factors and the rating of TVA's senior unsecured, long-term, non-credit-enhanced debt. TVA is required to pay an unused facility fee on the portion of the total $2.7 billion that TVA has not borrowed or committed under letters of credit. This fee, along with letter of credit fees, may fluctuate depending on the rating of TVA's senior unsecured, long-term, non-credit-enhanced debt. At September 30, 2022 and 2021, there were approximately $704 million and $1.2 billion of letters of credit outstanding under these facilities, and there were no borrowings outstanding. See Note 15 — Risk Management Activities and Derivative Transactions — Other Derivative Instruments — Collateral.

The following table provides additional information regarding TVA's funding available under the four long-term revolving credit facilities:
Summary of Long-Term Credit Facilities
At September 30, 2022
(in millions)
Maturity DateFacility LimitLetters of Credit OutstandingCash BorrowingsAvailability
 February 2024$150 $38 $— $112 
February 2025500 500 — — 
September 20261,000 99 — 901 
March 20271,000 67 — 933 
     Total$2,650 $704 $— $1,946 

TVA and the U.S. Treasury, pursuant to the TVA Act, have entered into a memorandum of understanding under which the U.S. Treasury provides TVA with a $150 million credit facility. This credit facility was renewed for 2023 with a maturity date of September 30, 2023. Access to this credit facility or other similar financing arrangements with the U.S. Treasury has been available to TVA since the 1960s. TVA can borrow under the U.S. Treasury credit facility only if it cannot issue Bonds in the market on reasonable terms, and TVA considers the U.S. Treasury credit facility a secondary source of liquidity. The interest rate on any borrowing under this facility is based on the average rate on outstanding marketable obligations of the U.S. with maturities from date of issue of 12 months or less. There were no outstanding borrowings under the facility at September 30, 2022. The availability of this credit facility may be impacted by how the U.S. government addresses the possibility of approaching its debt limit.

Lease/Leasebacks

    TVA previously entered into leasing transactions to obtain third-party financing for 24 peaking CTs as well as certain qualified technological equipment and software ("QTE"). Due to TVA's continuing involvement with the combustion turbine facilities and the QTE during the leaseback term, TVA accounted for the lease proceeds as financing obligations. At September 30, 2021, the outstanding leaseback obligations related to the remaining CTs and QTE were $25 million. There were no outstanding leaseback obligations related to the remaining CTs and QTE at September 30, 2022. Prior to 2021, TVA made final rent payments involving 16 CTs, and acquired the equity interest related to these transactions. Rent payments under the remaining CT lease/leaseback transactions were made through January 2022. TVA gave notice in December 2021 of its election to acquire the equity interests related to the remaining eight CTs for a total of $155 million. The associated acquisitions are expected to close in December 2022 and May 2023.

In October 2019, TVA provided notice of its intent to purchase the ownership interest in certain QTE through a series of installments. TVA made its last repurchase payment in December 2021, after which the associated leases were terminated.
v3.22.2.2
Risk Management Activities and Derivative Transactions
 12 Months Ended
Sep. 30, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Risk Management Activities and Derivative Transactions
TVA is exposed to various risks related to commodity prices, investment prices, interest rates, currency exchange rates, and inflation as well as counterparty credit and performance risks.  To help manage certain of these risks, TVA has historically entered into various derivative transactions, principally commodity option contracts, forward contracts, swaps, swaptions, futures, and options on futures.  Other than certain derivative instruments in its trust investment funds, it is TVA's policy to enter into these derivative transactions solely for hedging purposes and not for speculative purposes.

In November 2021, the TVA Board approved the elimination of the Value at Risk aggregate transaction limit for the FHP
and authorized the use of tolerances and measures that will be reviewed annually by the TVA Board. The tolerances will address counterparty exposure, liquidity risk, and reduction in fuel cost volatility. In addition, the TVA Board approved certain administrative changes to the FHP. In December 2021, TVA reinstated the FHP, and hedging activity began under the program in the second quarter of 2022.

Overview of Accounting Treatment

TVA recognizes certain of its derivative instruments as either assets or liabilities on its Consolidated Balance Sheets at fair value.  The accounting for changes in the fair value of these instruments depends on (1) whether TVA uses regulatory accounting to defer the derivative gains and losses, (2) whether the derivative instrument has been designated and qualifies for hedge accounting treatment, and (3) if so, the type of hedge relationship (for example, cash flow hedge).

The following tables summarize the accounting treatment that certain of TVA's financial derivative transactions receive:
Summary of Derivative Instruments That Receive Hedge Accounting Treatment (part 1) 
Amount of Mark-to-Market Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
For the years ended September 30
Derivatives in Cash Flow Hedging RelationshipObjective of Hedge TransactionAccounting for Derivative
Hedging Instrument		20222021
Currency swapsTo protect against changes in cash flows caused by changes in foreign currency exchange rates (exchange rate risk)Unrealized gains and losses are recorded in AOCI and reclassified to Interest expense to the extent they are offset by gains and losses on the hedged transaction$(157)$126 
Summary of Derivative Instruments That Receive Hedge Accounting Treatment (part 2)(1)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) to Interest Expense
For the years ended September 30
Derivatives in Cash Flow Hedging Relationship20222021
Currency swaps$(93)$97 
Note
(1) There were no amounts excluded from effectiveness testing for any of the periods presented. Based on forecasted foreign currency exchange rates, TVA expects to reclassify approximately $29 million of gains from AOCI to Interest expense within the next 12 months to offset amounts anticipated to be recorded in Interest expense related to the forecasted exchange loss on the debt.
Summary of Derivative Instruments That Do Not Receive Hedge Accounting Treatment
Amount of Gain (Loss) Recognized in Income on Derivatives(1)
For the years ended September 30
 
Derivative TypeObjective of DerivativeAccounting for Derivative Instrument20222021
Interest rate swapsTo fix short-term debt variable rate to a fixed rate (interest rate risk)Mark-to-market gains and losses are recorded as regulatory liabilities and assets, respectively

Realized gains and losses are recognized in Interest expense when incurred during the settlement period and are presented in operating cash flow		$(103)$(115)
Commodity derivatives
under the FHP		To protect against fluctuations in market prices of purchased commodities (price risk)
Mark-to-market gains and losses are recorded as regulatory liabilities and assets, respectively

Realized gains and losses are recognized in Fuel expense or Purchased power expense as the contracts settle to match the delivery period of the underlying commodity(2)
47 — 
Notes
(1) All of TVA's derivative instruments that do not receive hedge accounting treatment have unrealized gains (losses) that would otherwise be recognized in income but instead are deferred as regulatory liabilities and assets. As such, there were no related gains (losses) recognized in income for these unrealized gains (losses) for the years ended September 30, 2022 and 2021.
(2) Of the amount recognized in 2022, $38 million and $9 million were reported in Fuel expense and Purchased power expense, respectively.
Fair Values of TVA Derivatives
At September 30
 20222021
Derivatives That Receive Hedge Accounting Treatment:
 BalanceBalance Sheet PresentationBalanceBalance Sheet Presentation
Currency swaps    
£250 million Sterling
$(130)
Accounts payable and accrued liabilities $(7); Other long-term liabilities $(123)
$(36)
Accounts payable and accrued liabilities $(4); Other long-term liabilities $(32)
£150 million Sterling
(110)
Accounts payable and accrued liabilities $(5); Other long-term liabilities $(105)
(47)
Accounts payable and accrued liabilities $(3); Other long-term liabilities $(44)
Derivatives That Do Not Receive Hedge Accounting Treatment:
 BalanceBalance Sheet PresentationBalanceBalance Sheet Presentation
Interest rate swaps    
$1.0 billion notional
$(672)
Accounts payable and accrued liabilities $(9); Accrued interest $(33); Other long-term liabilities $(630)
$(1,182)
Accounts payable and
accrued liabilities $(44); Accrued interest $(37);
Other long-term liabilities
$(1,101)
$476 million notional
(233)
Accounts payable and accrued liabilities $(3); Accrued interest $(9); Other long-term liabilities $(221)
(455)
Accounts payable and
accrued liabilities $(22); Accrued interest $(10);
Other long-term liabilities
$(423)
$42 million notional(1)
— N/A(2)
Accounts payable and
accrued liabilities $(1); Accrued interest $(1)
Commodity contract derivatives 145 
Other current assets $118; Other long-term assets $34; Accounts payable and accrued liabilities $(6); Other long-term liabilities $(1)
247 
Other current assets $210; Other long-term assets $40; Accounts payable and accrued liabilities $(3)
Commodity derivatives under the FHP115 
Accounts receivable, net $1; Other current assets $54; Other long-term assets $68; Accounts payable and accrued liabilities $(8)
— N/A
Note
(1) At September 30, 2021, represented two interest rate swaps with notional amounts of $28 million and $14 million. In 2022, final payments were made on both of the interest rate swaps.

Cash Flow Hedging Strategy for Currency Swaps

To protect against exchange rate risk related to British pound sterling denominated Bond transactions, TVA entered into foreign currency hedges at the time the Bond transactions occurred.  TVA had the following currency swaps outstanding at September 30, 2022:
Currency Swaps Outstanding
Effective Date of Currency Swap ContractAssociated TVA Bond Issues Currency ExposureExpiration Date of SwapOverall Effective
Cost to TVA
2001£250 million20326.59%
2003£150 million20434.96%

When the dollar strengthens against the British pound sterling, the exchange gain on the Bond liability and related accrued interest is offset by an equal amount of loss on the swap contract that is reclassified out of AOCI.  Conversely, the exchange loss on the Bond liability and related accrued interest is offset by an equal amount of gain on the swap contract that is reclassified out of AOCI.  All such exchange gains or losses on the Bond liability and related accrued interest are included in Long-term debt, net and Accrued interest, respectively.  The offsetting exchange losses or gains on the swap contracts are recognized in AOCI.  If any gain (loss) were to be incurred as a result of the early termination of the foreign currency swap contract, the resulting income (expense) would be amortized over the remaining life of the associated Bond as a component of Interest expense. The values of the currency swap liabilities are included in Accounts payable and accrued liabilities and Other long-term liabilities on the Consolidated Balance Sheets.
    
Derivatives Not Receiving Hedge Accounting Treatment

Interest Rate Derivatives.  Generally TVA uses interest rate swaps to fix variable short-term debt to a fixed rate, and TVA uses regulatory accounting treatment to defer the MtM gains and losses on its interest rate swaps. The net deferred unrealized gains and losses are classified as regulatory liabilities or assets on TVA's Consolidated Balance Sheets and are included in the ratemaking formula when gains or losses are realized. The values of these derivatives are included in Accounts payable and accrued liabilities, Accrued interest, and Other long-term liabilities on the Consolidated Balance Sheets, and realized gains and losses, if any, are included on TVA's Consolidated Statements of Operations. For the years ended September 30, 2022 and 2021, the changes in fair market value of the interest rate swaps resulted in the reduction in unrealized losses of $728 million and $402 million, respectively.  TVA may hold short-term debt balances lower than the notional amount of the interest rate swaps from time to time due to changes in business conditions and other factors. While actual balances vary, TVA generally plans to maintain average balances of short-term debt equal to or in excess of the combined notional amount of the interest rate swaps.

Commodity Derivatives. TVA enters into certain derivative contracts for natural gas that require physical delivery of the contracted quantity of the commodity. TVA marks to market these natural gas contracts and defers the fair market values as regulatory assets or liabilities on a gross basis. At September 30, 2022, TVA's natural gas contract derivatives had terms of up to two years.
Commodity Contract Derivatives 
At September 30
 20222021
 
Number of Contracts
Notional AmountFair Value (MtM)
(in millions)		Number of ContractsNotional Amount
Fair Value (MtM)
(in millions)
Natural gas contract derivatives44296 million mmBtu$145 40263 million mmBtu$247 

Commodity Derivatives under the FHP. In December 2021, TVA reinstated the FHP, and hedging activity began under the program in the second quarter of 2022. Currently, TVA is hedging exposure to the price of natural gas under the FHP. There is no Value at Risk aggregate transaction limit under the current FHP structure, but the TVA Board reviews and authorizes the use of tolerances and measures annually. TVA's policy prohibits trading financial instruments under the FHP for speculative purposes. At September 30, 2022, TVA's natural gas swap contracts under the FHP had remaining terms of up to four years.

Commodity Derivatives under Financial Hedging Program(1)
At September 30, 2022At September 30, 2021
Number of Contracts
Notional Amount
Fair Value (MtM)
(in millions)
Number of Contracts
Notional Amount
Fair Value (MtM)
(in millions)
Natural gas
Swap contracts225256 million mmBtu$115 —— million mmBtu$— 
Note
(1) Fair value amounts presented are based on the net commodity position with the counterparty. Notional amounts disclosed represent the net value of contractual amounts.

TVA defers all FHP unrealized gains (losses) as regulatory liabilities (assets) and records the realized gains or losses in Fuel expense and Purchased power expense to match the delivery period of the underlying commodity.
Offsetting of Derivative Assets and Liabilities

    The amounts of TVA's derivative instruments as reported on the Consolidated Balance Sheets are shown in the table below:
Derivative Assets and Liabilities(1)
At September 30
(in millions)
20222021
Assets
Commodity contract derivatives $152 $250 
Commodity derivatives under the FHP(2)
123 — 
Total derivatives subject to master netting or similar arrangement$275 $250 
Liabilities
Currency swaps$240 $83 
Interest rate swaps(3)
905 1,639 
Commodity contract derivatives7 3 
Commodity derivatives under the FHP(2)
8 — 
Total derivatives subject to master netting or similar arrangement$1,160 $1,725 
Notes
(1) Offsetting amounts include counterparty netting of derivative contracts. Except as discussed below, there were no other material offsetting amounts on TVA's Consolidated Balance Sheets at either September 30, 2022 or 2021.
(2) At September 30, 2022, the gross derivative asset and gross derivative liability was $168 million and $53 million, respectively, with offsetting amounts for each totaling $45 million. TVA received $68 million of collateral from counterparties as of September 30, 2022, which is recorded separately from the fair values of the derivative assets and liabilities and reported in Accounts payable and accrued liabilities.
(3) Letters of credit of approximately $704 million and $1.2 billion were posted as collateral at September 30, 2022 and 2021, respectively, to partially secure the liability positions of one of the interest rate swaps in accordance with the collateral requirements for this derivative.

Other Derivative Instruments

Investment Fund Derivatives.  Investment funds consist primarily of funds held in the NDT, ART, SERP, and DCP.  See Note 16 — Fair Value Measurements — Investment Funds for a discussion of the trusts, plans, and types of investments.  The NDT and ART may invest in derivative instruments which may include swaps, futures, options, forwards, and other instruments.   At September 30, 2022 and 2021, the NDT held investments in forward contracts to purchase debt securities. The fair values of these derivatives were in net asset positions totaling $4 million and $2 million at September 30, 2022 and 2021, respectively.

Collateral.  TVA's interest rate swaps, currency swaps, and commodity derivatives under the FHP contain contract provisions that require a party to post collateral (in a form such as cash or a letter of credit) when the party's liability balance under the agreement exceeds a certain threshold.  At September 30, 2022, the aggregate fair value of all derivative instruments with credit-risk related contingent features that were in a liability position was $1.2 billion.  TVA's collateral obligations at September 30, 2022, under these arrangements were $602 million, for which TVA had posted $704 million in letters of credit.  These letters of credit reduce the available balance under the related credit facilities.  TVA's assessment of the risk of its nonperformance includes a reduction in its exposure under the interest rate swap contracts as a result of this posted collateral. In addition, as of September 30, 2022, TVA received $68 million of collateral from counterparties related to the commodity derivatives under the FHP.

For all of its derivative instruments with credit-risk related contingent features:
    
•If TVA remains a majority-owned U.S. government entity but Standard & Poor's Financial Services, LLC ("S&P") or Moody's Investors Service, Inc. ("Moody's") downgrades TVA's credit rating to AA or Aa2, respectively, TVA's collateral obligations would likely increase by $22 million, and

•If TVA ceases to be majority-owned by the U.S. government, TVA's credit rating would likely be downgraded and TVA would be required to post additional collateral.

Counterparty Risk

    TVA may be exposed to certain risks when a counterparty has the potential to fail to meet its obligations in accordance with agreed terms. These risks may be related to credit, operational, or nonperformance matters. To mitigate certain counterparty risk, TVA analyzes the counterparty's financial condition prior to entering into an agreement, establishes credit limits, monitors the appropriateness of those limits, as well as any changes in the creditworthiness of the counterparty, on an ongoing basis, and when required, employs credit mitigation measures, such as collateral or prepayment arrangements and master purchase and sale agreements.
Customers.  TVA is exposed to counterparty credit risk associated with trade accounts receivable from delivered power sales to LPCs, and from industries and federal agencies directly served, all located in the Tennessee Valley region. Of the $1.9 billion and $1.5 billion of receivables from power sales outstanding at September 30, 2022 and 2021, respectively, nearly all counterparties were rated investment grade. The obligations of customers that are not investment grade are secured by collateral. TVA is also exposed to risk from exchange power arrangements with a small number of investor-owned regional utilities related to either delivered power or the replacement of open positions of longer-term purchased power or fuel agreements. TVA believes its policies and procedures for counterparty performance risk reviews have generally protected TVA against significant exposure related to market and economic conditions. See Note 1 — Summary of Significant Accounting Policies — Allowance for Uncollectible Accounts, Note 3 — Accounts Receivable, Net, and Note 9 — Other Long-Term Assets.
TVA had revenue from two LPCs that collectively accounted for 17 percent of total operating revenues for both the years ended September 30, 2022 and 2021.

Suppliers.  TVA assesses potential supplier performance risks, including procurement of fuel, parts, and services. If suppliers are unable to perform under TVA's existing contracts or if TVA is unable to obtain similar services or supplies from other vendors, TVA could experience delays, disruptions, additional costs, or other operational outcomes that may impact generation, maintenance, and capital programs. If certain fuel or purchased power suppliers fail to perform under the terms of their contract with TVA, TVA might lose the money that it paid to the supplier under the contract and have to purchase replacement fuel or power on the spot market, perhaps at a significantly higher price than TVA was entitled to pay under the contract. In addition, TVA might not be able to acquire replacement fuel or power in a timely manner and thus might be unable to satisfy its own obligations to deliver power. TVA continues evaluating potential supplier performance risks and supplier impact but cannot determine or predict the duration of such risks/impacts or the extent to which such risks/impacts could affect TVA's business, operations, and financial results or cause potential business disruptions.

TVA has experienced an increase in supplier impacts as a result of Coronavirus Disease 2019 ("COVID-19") and the state of global supply chains and the economy, such as project delays, limited availability of supplies, and price increases. Russia's invasion of Ukraine has further intensified the state of global supply chains and inflationary pressures, and TVA will continue to monitor these pressures.

Natural Gas. TVA purchases a significant amount of its natural gas requirements through contracts with a variety of suppliers and purchases substantially all of its fuel oil requirements on the spot market. TVA delivers to its gas fleet under firm and non-firm transportation contracts on multiple interstate natural gas pipelines. TVA contracts for storage capacity that allows for operational flexibility and increased supply during peak gas demand scenarios or supply disruptions. TVA plans to continue using contracts of various lengths and terms to meet the projected natural gas needs of its natural gas fleet. TVA also maintains on-site, fuel oil backup to operate at the majority of the combustion turbine sites in the event of major supply disruptions. In the event suppliers are unable to perform under existing contracts, TVA can utilize its storage portfolio or other suppliers to help secure replacement natural gas volumes.

    Coal. To ensure a reliable supply of coal, TVA had coal contracts with multiple suppliers at September 30, 2022. The contracted supply of coal is sourced from several geographic regions of the U.S. and is delivered via barge and rail. As a result of emerging technologies, environmental regulations, industry trends, and natural gas market volatility over the past few years, coal suppliers are facing increased financial pressure, which has led to relatively poor credit ratings and bankruptcies, restructuring, mine closures, or other scenarios. A long-term continued decline in demand for coal could result in more consolidations, additional bankruptcies, restructuring, mine closures, or other scenarios. Current market conditions indicate limited availability of spot market coal due to increased exports, utility demand, and mine capacity and capability.

TVA experienced challenges in 2021 related to coal supply, as a result of supply limitation and transportation challenges. Coal supply and transportation continued to be constrained in 2022, and these constraints are anticipated to continue into 2023. Rail service continues to limit TVA’s ability to receive contracted supply, and TVA is also seeing supply constraints and price increases for reagents, diesel fuel, and fuel surcharges associated with coal transport, which are also expected to continue. TVA will continue to monitor the coal supply challenges and utilize its contracting strategy and diverse generation portfolio to balance needs and ensure adequate fuel supplies.

    Nuclear Fuel. Nuclear fuel is obtained predominantly through long-term uranium concentrate supply contracts, contracted conversion services, contracted enrichment services, or a combination thereof, and contracted fuel fabrication services. The supply markets for uranium concentrates and certain nuclear fuel services are subject to price fluctuations and availability restrictions. Supply market conditions may make procurement contracts subject to credit risk related to the potential nonperformance of counterparties. In the event of nonperformance by these or other suppliers, TVA believes that replacement uranium concentrate and nuclear fuel services can be obtained, although at prices that may be unfavorable when compared to the prices under the current supply agreements.

As a result of Russia’s invasion of Ukraine, new contracts for Russian origin nuclear fuel have been limited by Executive Order 14066, and further restrictions on the purchase or use of Russian origin fuel may be forthcoming. TVA should have no direct impact from existing or future restrictions since TVA has no Russian origin nuclear fuel in inventory for use in its reactors and it is not contracted to purchase any Russian origin nuclear fuel. TVA could be impacted by higher market prices as a result
of general market impacts associated with supply restrictions; however, at this time TVA's nuclear fuel is obtained predominantly through long-term contracts.

    Purchased Power. TVA acquires power from a variety of power producers through long-term and short-term PPAs as well as through spot market purchases. Because of the long-term nature and reliability of purchased power, TVA requires that the PPAs contain certain counterparty performance assurance requirements to help insure counterparty performance during the term of the agreements.

Other Suppliers. Mounting solar supply chain constraints, commodity price increases, and the recent trade policy investigation into solar panel imports have created challenges for the U.S. solar industry, threatening project delays, cancellations, and price increases. These constraints are affecting contracted PPAs from previous requests for proposals that are not yet online and TVA's Self-Directed Solar project.

Derivative Counterparties.  TVA has entered into physical and financial contracts that are classified as derivatives for hedging purposes, and TVA's NDT, ART, and qualified defined benefit plan ("pension plan") have entered into derivative contracts for investment purposes. If a counterparty to one of the physical or financial derivative transactions defaults, TVA might incur costs in connection with entering into a replacement transaction. If a counterparty to the derivative contracts into which the NDT, the ART, or the pension plan have entered for investment purposes defaults, the value of the investment could decline significantly or perhaps become worthless. TVA has concentrations of credit risk from the banking, coal, and gas industries because multiple companies in these industries serve as counterparties to TVA in various derivative transactions. At September 30, 2022, all of TVA's commodity derivatives under the FHP, currency swaps, and interest rate swaps were with counterparties whose Moody's credit ratings were A2 or higher.
TVA classifies forward natural gas contracts as derivatives. See Derivatives Not Receiving Hedge Accounting Treatment above. At September 30, 2022, the natural gas contracts were with counterparties whose ratings ranged from B1 to A1.
v3.22.2.2
Fair Value Measurements
 12 Months Ended
Sep. 30, 2022
Fair Value Disclosures [Abstract]  
Fair Value Measurements
Fair value is determined based on the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the asset or liability's principal market, or in the absence of a principal market, the most advantageous market for the asset or liability in an orderly transaction between market participants. TVA uses market or observable inputs as the preferred source of values, followed by assumptions based on hypothetical transactions in the absence of market inputs.

Valuation Techniques

The measurement of fair value results in classification into a hierarchy by the inputs used to determine the fair value as follows:
Level 1—
 		Unadjusted quoted prices in active markets accessible by the reporting entity for identical assets or liabilities.  Active markets are those in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing.
Level 2
 		—
 		Pricing inputs other than quoted market prices included in Level 1 that are based on observable market data and that are directly or indirectly observable for substantially the full term of the asset or liability.  These include quoted market prices for similar assets or liabilities, quoted market prices for identical or similar assets in markets that are not active, adjusted quoted market prices, inputs from observable data such as interest rate and yield curves, volatilities and default rates observable at commonly quoted intervals, and inputs derived from observable market data by correlation or other means.
Level 3—
 
Pricing inputs that are unobservable, or less observable, from objective sources.  Unobservable inputs are only to be used to the extent observable inputs are not available.  These inputs maintain the concept of an exit price from the perspective of a market participant and should reflect assumptions of other market participants.  An entity should consider all market participant assumptions that are available without unreasonable cost and effort.  These are given the lowest priority and are generally used in internally developed methodologies to generate management's best estimate of the fair value when no observable market data is available.

A financial instrument's level within the fair value hierarchy (where Level 1 is the highest and Level 3 is the lowest) is based on the lowest level of input significant to the fair value measurement.

The following sections describe the valuation methodologies TVA uses to measure different financial instruments at fair value. Except for gains and losses on SERP and DCP assets, all changes in fair value of these assets and liabilities have been recorded as changes in regulatory assets, regulatory liabilities, or AOCI on TVA's Consolidated Balance Sheets and Consolidated Statements of Comprehensive Income (Loss). Except for gains and losses on SERP and DCP assets, there has been no impact to the Consolidated Statements of Operations or the Consolidated Statements of Cash Flows related to these fair value measurements.
Investment Funds

    At September 30, 2022, Investment funds were comprised of $3.7 billion of equity securities and debt securities classified as trading measured at fair value. Equity and trading debt securities are held in the NDT, ART, SERP, and DCP. The NDT holds funds for the ultimate decommissioning of TVA's nuclear power plants. The ART holds funds primarily for the costs related to the future closure and retirement of TVA's other long-lived assets. The balances in the NDT and ART were $2.5 billion and $1.1 billion, respectively, at September 30, 2022.

TVA established a SERP to provide benefits to selected employees of TVA which are comparable to those provided by competing organizations. The DCP is designed to provide participants with the ability to defer compensation to future periods. The NDT, ART, SERP, and DCP funds are invested in portfolios of securities generally designed to achieve a return in line with overall equity and debt market performance.

The NDT, ART, SERP, and DCP are composed of multiple types of investments and are managed by external institutional investment managers. Most U.S. and international equities, U.S. Treasury inflation-protected securities ("TIPS"), real estate investment trust securities, and cash securities and certain derivative instruments are measured based on quoted exchange prices in active markets and are classified as Level 1 valuations. Fixed-income investments, high-yield fixed-income investments, currencies, and most derivative instruments are non-exchange traded and are classified as Level 2 valuations. These measurements are based on market and income approaches with observable market inputs.

    Private equity limited partnerships, private real asset investments, and private credit investments may include holdings of investments in private real estate, venture capital, buyout, mezzanine or subordinated debt, restructuring or distressed debt, and special situations through funds managed by third-party investment managers. These investments generally involve a three-to-four-year period where the investor contributes capital, followed by a period of distribution, typically over several years. The investment period is generally, at a minimum, 10 years or longer. The NDT had unfunded commitments related to private equity limited partnerships of $187 million, private real assets of $128 million, and private credit of $57 million at September 30, 2022. The ART had unfunded commitments related to limited partnerships in private equity of $104 million, private real assets of $75 million, and private credit of $32 million at September 30, 2022. These investments have no redemption or limited redemption options and may also impose restrictions on the NDT's and ART's ability to liquidate their investments. There are no readily available quoted exchange prices for these investments. The fair value of these investments is based on information provided by the investment managers. These investments are valued on a quarterly basis. TVA's private equity limited partnerships, private real asset investments, and private credit investments are valued at net asset values ("NAV") as a practical expedient for fair value. TVA classifies its interest in these types of investments as investments measured at NAV in the fair value hierarchy.

Commingled funds represent investment funds comprising multiple individual financial instruments. The commingled funds held by the NDT, ART, SERP, and DCP consist of either a single class of securities, such as equity, debt, or foreign currency securities, or multiple classes of securities. All underlying positions in these commingled funds are either exchange traded or measured using observable inputs for similar instruments. The fair value of commingled funds is based on NAV per fund share (the unit of account), derived from the prices of the underlying securities in the funds. These commingled funds can be redeemed at the measurement date NAV and are classified as Commingled funds measured at NAV in the fair value hierarchy.

     Realized and unrealized gains and losses on equity and trading debt securities are recognized in current earnings and are based on average cost. The gains and losses of the NDT and ART are subsequently reclassified to a regulatory asset or liability account in accordance with TVA's regulatory accounting policy. See Note 1 — Summary of Significant Accounting Policies — Cost-Based Regulation and Note 10 — Regulatory Assets and Liabilities. TVA recorded unrealized gains and losses related to its equity and trading debt securities held during each period as follows:
Unrealized Investment Gains (Losses)
For the years ended September 30
(in millions)
FundFinancial Statement Presentation20222021
NDTRegulatory assets$(396)$279 
ARTRegulatory assets(190)145 
SERPOther income, net(19)7 
DCPOther income, net(5)1 

Currency and Interest Rate Swap Derivatives

See Note 15 — Risk Management Activities and Derivative Transactions — Cash Flow Hedging Strategy for Currency Swaps and Derivatives Not Receiving Hedge Accounting Treatment for a discussion of the nature, purpose, and contingent features of TVA's currency swaps and interest rate swaps. These swaps are classified as Level 2 valuations and are valued based on income approaches using observable market inputs for similar instruments.
Commodity Contract Derivatives and Commodity Derivatives under the FHP

Commodity Contract Derivatives. Most of these derivative contracts are valued based on market approaches, which utilize short-term and mid-term market-quoted prices from an external industry brokerage service.

Commodity Derivatives under the FHP. Swap contracts are valued using a pricing model based on New York Mercantile Exchange inputs and are subject to nonperformance risk outside of the exit price. These contracts are classified as Level 2 valuations.

See Note 15 — Risk Management Activities and Derivative Transactions — Derivatives Not Receiving Hedge Accounting Treatment — Commodity Derivatives and — Commodity Derivatives under the FHP.

Nonperformance Risk

The assessment of nonperformance risk, which includes credit risk, considers changes in current market conditions, readily available information on nonperformance risk, letters of credit, collateral, other arrangements available, and the nature of master netting arrangements. TVA is a counterparty to currency swaps, interest rate swaps, commodity contracts, and other derivatives which subject TVA to nonperformance risk. Nonperformance risk on the majority of investments and certain exchange-traded instruments held by TVA is incorporated into the exit price that is derived from quoted market data that is used to mark the investment to market.

Nonperformance risk for most of TVA's derivative instruments is an adjustment to the initial asset/liability fair value. TVA adjusts for nonperformance risk, both of TVA (for liabilities) and the counterparty (for assets), by applying credit valuation adjustments ("CVAs"). TVA determines an appropriate CVA for each applicable financial instrument based on the term of the instrument and TVA's or the counterparty's credit rating as obtained from Moody's. For companies that do not have an observable credit rating, TVA uses internal analysis to assign a comparable rating to the counterparty. TVA discounts each financial instrument using the historical default rate (as reported by Moody's for CY 1983 to CY 2021) for companies with a similar credit rating over a time period consistent with the remaining term of the contract. The application of CVAs resulted in a $2 million decrease in the fair value of assets and a $2 million decrease in the fair value of liabilities at September 30, 2022.

Fair Value Measurements

The following tables set forth by level, within the fair value hierarchy, TVA's financial assets and liabilities that were measured at fair value on a recurring basis at September 30, 2022 and 2021. Financial assets and liabilities have been classified in their entirety based on the lowest level of input that is significant to the fair value measurement. TVA's assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the determination of the fair value of the assets and liabilities and their classification in the fair value hierarchy levels.
Fair Value Measurements
At September 30, 2022
(in millions)
Quoted Prices in Active
 Markets for
Identical Assets
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Assets
Investments    
Equity securities$534 $— $— $534 
Government debt securities(1)
358 36 — 394 
Corporate debt securities(2)
— 283 — 283 
Mortgage and asset-backed securities— 52 — 52 
Institutional mutual funds242 — — 242 
Forward debt securities contracts— 4 — 4 
Private equity funds measured at net asset value(3)
— — — 487 
Private real asset funds measured at net asset value(3)
— — — 369 
Private credit measured at net asset value(3)
— — — 103 
Commingled funds measured at net asset value(3)
— — — 1,203 
Total investments1,134 375 — 3,671 
Commodity contract derivatives— 152 — 152 
Commodity derivatives under the FHP— 123 — 123 
Total$1,134 $650 $— $3,946 
Quoted Prices in Active Markets for Identical Liabilities
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Liabilities
Currency swaps(4)
$— $240 $— $240 
Interest rate swaps— 905 — 905 
Commodity contract derivatives— 7 — 7 
Commodity derivatives under the FHP— 8 — 8 
Total$— $1,160 $— $1,160 
Notes
(1) Includes government-sponsored entities, including $358 million of U.S. Treasury securities within Level 1 of the fair value hierarchy.
(2) Includes both U.S. and foreign debt.
(3) Certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been categorized in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented on the Consolidated Balance Sheets.
(4) TVA records currency swaps net of cash collateral received from or paid to the counterparty if applicable, to the extent such amount is not recorded in Accounts payable and accrued liabilities. See Note 15 — Risk Management Activities and Derivative Transactions — Offsetting of Derivative Assets and Liabilities.
Fair Value Measurements
At September 30, 2021
(in millions)
Quoted Prices in Active
 Markets for
Identical Assets
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Assets
Investments    
Equity securities$634 $— $— $634 
Government debt securities(1)
573 24 — 597 
Corporate debt securities(2)
— 411 — 411 
Mortgage and asset-backed securities— 63 — 63 
Institutional mutual funds225 — — 225 
Forward debt securities contracts— 2 — 2 
Private equity funds measured at net asset value(3)
— — — 357 
Private real asset funds measured at net asset value(3)
— — — 272 
    Private credit measured at net asset value(3)
— — — 71 
Commingled funds measured at net asset value(3)
— — — 1,421 
Total investments1,432 500 — 4,053 
Commodity contract derivatives— 250 — 250 
Total$1,432 $750 $— $4,303 
Quoted Prices in Active Markets for Identical Liabilities
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Liabilities
Currency swaps(4)
$— $83 $— $83 
Interest rate swaps— 1,639 — 1,639 
Commodity contract derivatives— 3 — 3 
Total$— $1,725 $— $1,725 
Notes
(1) Includes government-sponsored entities, including $573 million of U.S. Treasury securities within Level 1 of the fair value hierarchy.
(2) Includes both U.S. and foreign debt.
(3) Certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been categorized in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented on the Consolidated Balance Sheets.
(4) TVA records currency swaps net of cash collateral received from or paid to the counterparty, to the extent such amount is not recorded in Accounts payable and accrued liabilities. See Note 15 — Risk Management Activities and Derivative Transactions — Offsetting of Derivative Assets and Liabilities.



Other Financial Instruments Not Recorded at Fair Value

TVA uses the methods and assumptions described below to estimate the fair value of each significant class of financial instruments. The fair value of the financial instruments held at September 30, 2022 and 2021, may not be representative of the actual gains or losses that will be recorded when these instruments mature or are called or presented for early redemption. The estimated values of TVA's financial instruments not recorded at fair value at September 30, 2022 and 2021, were as follows:
Estimated Values of Financial Instruments Not Recorded at Fair Value
(in millions)
 At September 30, 2022At September 30, 2021
 Valuation ClassificationCarrying
Amount		Fair
Value		Carrying
Amount		Fair
Value
EnergyRight® receivables, net (including current portion)
Level 2$62 $62 $72 $71 
Loans and other long-term receivables, net (including current portion)Level 2105 96 99 94 
EnergyRight® financing obligations (including current portion)
Level 272 81 82 92 
Unfunded loan commitmentsLevel 2— — — 3 
Membership interests of VIEs subject to mandatory redemption (including current portion)Level 220 22 23 30 
Long-term outstanding power bonds, net (including current maturities)Level 217,856 18,070 18,485 24,309 
Long-term debt of VIEs, net (including current maturities)Level 21,007 989 1,049 1,307 

The carrying value of Cash and cash equivalents, Restricted cash and cash equivalents, Accounts receivable, net, and Short-term debt, net approximate their fair values.

The fair value for loans and other long-term receivables is estimated by determining the present value of future cash flows using a discount rate equal to lending rates for similar loans made to borrowers with similar credit ratings and for similar remaining maturities, where applicable. The fair value of long-term debt and membership interests of VIEs subject to mandatory redemption is estimated by determining the present value of future cash flows using current market rates for similar obligations, giving effect to credit ratings and remaining maturities.
v3.22.2.2
Other Income (Expense), Net
 12 Months Ended
Sep. 30, 2022
Other Income and Expenses [Abstract]  
Other Income (Expense), Net
Income and expenses not related to TVA's operating activities are summarized in the following table:
Other Income, Net
For the years ended September 30
(in millions)
 202220212020
Bellefonte$— $(28)$— 
Interest income15 12 18 
External services16 13 12 
Gains (losses) on investments(17)16 9 
Miscellaneous(7)— (3)
Total other income, net$7 $13 $36 
v3.22.2.2
Related Parties
 12 Months Ended
Sep. 30, 2022
Related Party Transactions [Abstract]  
Related Parties
TVA is a wholly-owned corporate agency of the federal government, and because of this relationship, TVA's revenues and expenses are included as part of the federal budget as a revolving fund.  TVA's purpose and responsibilities as an agency are described under the "Other Agencies" section of the federal budget.

TVA's power program and stewardship (nonpower) programs were originally funded primarily by appropriations from Congress.  In 1959, Congress passed an amendment to the TVA Act that required TVA's power program to be self-financing from power revenues and proceeds from power program financings.  While TVA's power program did not directly receive appropriated funds after it became self-financing, TVA continued to receive appropriations for certain multipurpose and other nonpower mission-related activities as well as for its stewardship activities.  TVA has not received any appropriations from Congress for any activities since 1999, and since that time, TVA has funded stewardship program activities primarily with power revenues.

The 1959 amendment to the TVA Act also required TVA, beginning in 1961, to make annual payments to the U.S. Treasury from net power proceeds as a repayment of and as a return on the Power Program Appropriation Investment until a total of $1.0 billion of the Power Program Appropriation Investment has been repaid in accordance with the 1959 amendment.   TVA fulfilled its requirement to repay $1.0 billion of the Power Program Appropriation Investment in 2014. The TVA Act requires TVA to continue making payments to the U.S. Treasury as a return on the remaining $258 million of the Power Program Appropriation Investment.

TVA paid the U.S. Treasury $4 million, $4 million, and $6 million in 2022, 2021, and 2020, respectively, as a return on the Power Program Appropriation Investment.  The amount of the return on the Power Program Appropriation Investment is based on the Power Program Appropriation Investment balance at the beginning of that year and the computed average interest rate payable by the U.S. Treasury on its total marketable public obligations at the same date.  The interest rates payable by TVA
on the Power Program Appropriation Investment were 1.47 percent, 1.64 percent, and 2.44 percent for 2022, 2021, and 2020, respectively.

TVA also has access to a financing arrangement with the U.S. Treasury pursuant to the TVA Act.  TVA and the U.S. Treasury entered into a memorandum of understanding under which the U.S. Treasury provides TVA with a $150 million credit facility.  This credit facility has a maturity date of September 30, 2023, and is typically renewed annually.  Access to this credit facility or other similar financing arrangements has been available to TVA since the 1960s.  See Note 14 — Debt and Other Obligations — Credit Facility Agreements.

In the normal course of business, TVA contracts with other federal agencies for sales of electricity and other services.   Transactions with agencies of the federal government were as follows:
Related Party Transactions
At or for the years ended September 30
(in millions)
 202220212020
Revenue from sales of electricity$134 $109 $105 
Other income296 280 260 
Expenditures
Operating expenses228 214 224 
Additions to property, plant, and equipment11 10 9 
Cash and cash equivalents30 30 31 
Accounts receivable, net78 65 94 
Investment funds358 573 485 
Long-term accounts receivable43 31 27 
Accounts payable and accrued liabilities42 15 39 
Long-term power bonds, net1 1 1 
Return on power program appropriation investment4 4 6 
v3.22.2.2
Subsequent Events (Notes)
 12 Months Ended
Sep. 30, 2022
Subsequent Events [Abstract]  
Subsequent Events [Text Block] . Subsequent Events
Valuation Changes in Derivative Transactions

As of November xx, 2022, TVA’s interest rate swap derivative liability and related regulatory asset for unrealized losses are estimated to decrease approximately $120 million compared to September 30, 2022, due to increases in market interest rates.

As of November xx, 2022, TVA’s commodity contract derivative asset and related regulatory liability for unrealized gains are estimated to decrease approximately $48 million compared to September 30, 2022. The commodity derivative liability and related regulatory asset for unrealized losses are estimated to decrease $2 million compared to September 30, 2022. TVA's commodity derivative asset under the FHP and related regulatory liability for unrealized gains are estimated to decrease approximately $50 million compared to September 30, 2022. TVA’s commodity derivative liability under the FHP and related regulatory asset for unrealized losses is estimated to increase approximately $27 million compared to September 30, 2022. These changes are primarily due to recent decreases in natural gas prices.
v3.22.2.2
Plant Closures (Text Block)
 12 Months Ended
Sep. 30, 2022
Property, Plant and Equipment [Abstract]  
Plant Closures
7. Plant Closures

Background

TVA must continuously evaluate all generating assets to ensure an optimal energy portfolio that provides safe, clean, and reliable power while maintaining flexibility and fiscal responsibility to the people of the Tennessee Valley. Based on results of assessments presented to the TVA Board in 2019, the retirement of Bull Run Fossil Plant ("Bull Run") by December 2023 was approved. In addition, TVA is evaluating the impact of retiring the balance of the coal-fired fleet by 2035, and that evaluation includes environmental reviews, public input, and TVA Board approval. Due to these evaluations, certain planning assumptions were updated, and their financial impacts are discussed below.

Financial Impact

TVA's policy is to adjust depreciation rates to reflect the most current assumptions, ensuring units will be fully depreciated by the applicable retirement dates. As a result of TVA's decision to accelerate the retirement of Bull Run, TVA has recognized a cumulative $482 million of accelerated depreciation since the second quarter of 2019. Of this amount, $140 million, $136 million, and $125 million were recognized for the years ended September 30, 2022, 2021, and 2020, respectively.

In addition, service lives for Cumberland Fossil Plant ("Cumberland"), Gallatin Fossil Plant ("Gallatin"), Kingston Fossil Plant ("Kingston"), and Shawnee Fossil Plant ("Shawnee") were shortened in a new depreciation study implemented during the first quarter of 2022 to reflect current planning assumptions to potentially retire the remainder of the coal-fired fleet by 2035. As a result, TVA recognized an estimated $339 million of additional depreciation related to these four coal-fired plants during the year ended September 30, 2022. This estimate represents the effect of using the new depreciation rates on the property, plant, and equipment balances at September 30, 2021, and does not include any potential impact from additions to or retirements of net completed plant, that occurred since September 30, 2021.

For the years ended September 30, 2022, 2021, and 2020, respectively, TVA also recognized $22 million, $4 million, and $13 million in Operating and maintenance expense related to additional inventory reserves and project write-offs for the coal-fired fleet, including Bull Run.
v3.22.2.2
Leases (Text Block)
 12 Months Ended
Sep. 30, 2022
Leases [Abstract]  
Lessee, Operating Leases
8. Leases

    The following table provides information regarding the presentation of leases on the Consolidated Balance Sheets:
Amounts Recognized on TVA's Consolidated Balance Sheets
At September 30
(in millions)
20222021
Assets
  OperatingOperating lease assets, net of amortization$155 $165 
  FinanceFinance leases630 692 
Total lease assets$785 $857 
Liabilities
Current
  OperatingAccounts payable and accrued liabilities$59 $40 
  FinanceAccounts payable and accrued liabilities59 60 
Non-current
  OperatingOther long-term liabilities93 122 
  FinanceFinance lease liabilities628 687 
Total lease liabilities$839 $909 

    TVA's leases consist primarily of railcars, equipment, real estate/land, power generating facilities, and gas pipelines. TVA's leases have various terms and expiration dates remaining from less than one year to approximately 24 years. The components of lease costs were as follows:
Lease Costs
For the years ended September 30
(in millions)
202220212020
Operating lease costs(1)
$56 $52 $84 
Variable lease costs(1)
78 75 75 
Short-term lease costs(1)
26 12 7 
Finance lease costs
Amortization of lease assets(2)
58 51 15 
Interest on lease liabilities(3)(4)
42 39 33 
Total finance lease costs100 90 48 
     Total lease costs$260 $229 $214 
Notes
(1) Costs are included in Operating and maintenance expense, Fuel expense, Purchased power expense, and Tax equivalents expense on the Consolidated Statements of Operations.
(2) Expense is included in Depreciation and amortization expense on the Consolidated Statements of Operations.
(3) Expense is included in Interest expense on the Consolidated Statements of Operations.
(4) Certain finance leases receive regulatory accounting treatment and are reclassified to Fuel expense and Purchased power expense.

    TVA's variable lease costs are primarily related to renewable energy purchase agreements that require TVA to purchase all output from the underlying facility. Payments under those agreements are solely based on the actual output over the lease term. Certain TVA lease agreements contain renewal options. Those renewal options that are reasonably certain to be exercised are included in the lease measurements.
The following table contains additional information with respect to cash and non-cash activities related to leases:
Amounts Recognized on TVA's Consolidated Statements of Cash Flows
For the years ended September 30
(in millions)
202220212020
Operating cash flows for operating leases$57 $53 $85 
Operating cash flows for finance leases42 39 33 
Financing cash flows for finance leases60 52 15 
Lease assets obtained in exchange for lease obligations (non-cash)
Operating leases(1)
$43 $(22)$110 
Finance leases— 233 394 
Note
(1) Amount for 2021 represents a non-cash reduction due to a lease that was amended during the fiscal year resulting in derecognition of the operating lease asset and obligation upon remeasurement.

TVA has certain finance leases under PPAs under which the present value of the minimum lease payments exceeds the fair value of the related lease asset at the date of measurement.  This resulted in an interest rate that was higher than TVA's incremental borrowing rate. The weighted average remaining lease term in years and the weighted average discount rate for TVA's operating and financing leases were as follows:
Weighted Averages
At September 30
20222021
Weighted average remaining lease terms
Operating leases3 years5 years
Finance leases11 years12 years
Weighted average discount rate(1)
Operating leases1.5%1.5%
Finance leases17.8%17.7%
Note
(1) The discount rate is calculated using the rate implicit in a lease if it is readily determinable. If the rate used by the lessor is not readily determinable, TVA uses its incremental borrowing rate as permitted by accounting guidance. The incremental borrowing rate is influenced by TVA's credit rating and lease term and as such may differ for individual leases, embedded leases, or portfolios of leased assets.
    The following table presents maturities of lease liabilities and a reconciliation of the undiscounted cash flows to lease liabilities at September 30, 2022:
Future Minimum Lease Payments
Minimum payments due at September 30, 2022
(in millions)
Operating leases
2023$61 
202443 
202535 
202610 
20272 
Thereafter5 
Minimum annual payments156 
Less: present value discount(4)
Operating present value of net minimum lease payments$152 
Finance leases
2023$112 
2024107 
2025106 
2026105 
2027104 
   Thereafter552 
Minimum annual payments1,086 
Less: amount representing interest(399)
Finance present value of net minimum lease payments$687 

TVA has entered into five PPAs with renewable resource providers for solar generation and rights to charge and discharge battery energy storage systems. The systems are considered a lease component in these agreements. These PPAs have terms of 20 years, and are expected to commence between April 2023 and December 2024. Payments made over the term of these PPAs are expected to total approximately $414 million.

During the fourth quarter of 2022, TVA entered into an office lease with a term of approximately 11 years and an expected commencement date of April 2023. Payments made over the term of this lease are expected to total approximately $15 million.
v3.22.2.2
Deferred Costs, Capitalized, Prepaid, and Other Assets - Text Block
 12 Months Ended
Sep. 30, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]  
Other Current Assets
5. Other Current Assets

Other current assets consisted of the following:
Other Current Assets 
At September 30
(in millions)
 20222021
Commodity contract derivative assets$172 $210 
Other85 77 
Other current assets$257 $287 

Commodity Contract Derivative Assets. TVA enters into certain derivative contracts for natural gas that require physical
delivery of the contracted quantity of the commodity. TVA also reinstated the Financial Hedging Program ("FHP") (formerly the
Financial Trading Program, which was suspended in 2014) in December 2021, and hedging activity began under the program in
the second quarter of 2022. Commodity contract derivative assets classified as current include deliveries or settlements that will
occur within 12 months or less. See Note 15 — Risk Management Activities and Derivative Transactions — Derivatives Not Receiving Hedge Accounting Treatment — Commodity Derivatives and — Commodity Derivatives under the FHP for a discussion of TVA's commodity contract derivatives.
v3.22.2.2
Summary of Significant Accounting Policies [Policy Text Block]
 12 Months Ended
Sep. 30, 2022
Accounting Policies [Abstract]  
General
General

The Tennessee Valley Authority ("TVA") is a corporate agency and instrumentality of the United States ("U.S.") that was created in 1933 by federal legislation in response to a proposal by President Franklin D. Roosevelt.  TVA was created to, among other things, improve navigation on the Tennessee River, reduce the damage from destructive flood waters within the Tennessee River system and downstream on the lower Ohio and Mississippi Rivers, further the economic development of TVA's service area in the southeastern U.S., and sell the electricity generated at the facilities TVA operates. Today, TVA operates the nation's largest public power system and supplies power in most of Tennessee, northern Alabama, northeastern Mississippi, and southwestern Kentucky and in portions of northern Georgia, western North Carolina, and southwestern Virginia to a population of approximately 10 million people.

    TVA also manages the Tennessee River, its tributaries, and certain shorelines to provide, among other things, year-round navigation, flood damage reduction, and affordable and reliable electricity. Consistent with these primary purposes, TVA also manages the river system and public lands to provide recreational opportunities, adequate water supply, improved water quality, cultural and natural resource protection, and economic development. TVA performs these management duties in cooperation with other federal and state agencies that have jurisdiction and authority over certain aspects of the river system. In addition, the TVA Board of Directors ("TVA Board") has established two councils — the Regional Resource Stewardship Council and the Regional Energy Resource Council — to advise TVA on its stewardship activities in the Tennessee Valley and its energy resource activities.

The power program has historically been separate and distinct from the stewardship programs.  It is required to be self-supporting from power revenues and proceeds from power financings, such as proceeds from the issuance of bonds, notes, or other evidences of indebtedness (collectively, "Bonds").  Although TVA does not currently receive Congressional appropriations, it is required to make annual payments to the United States Department of the Treasury ("U.S. Treasury") as a return on the government's appropriation investment in TVA's power facilities (the "Power Program Appropriation Investment").  In the 1998 Energy and Water Development Appropriations Act, Congress directed TVA to fund essential stewardship activities related to its management of the Tennessee River system and nonpower or stewardship properties with power revenues in the event that there were insufficient appropriations or other available funds to pay for such activities in any fiscal year.  Congress has not
provided any appropriations to TVA to fund such activities since 1999.  Consequently, during 2000, TVA began paying for essential stewardship activities primarily with power revenues, with the remainder funded with user fees and other forms of revenues derived in connection with those activities.  The activities related to stewardship properties do not meet the criteria of an operating segment under accounting principles generally accepted in the United States of America ("GAAP").  Accordingly, these assets and properties are included as part of the power program, TVA's only operating segment.

Power rates are established by the TVA Board as authorized by the Tennessee Valley Authority Act of 1933, as amended, 16 U.S.C. §§ 831-831ee ("TVA Act").  The TVA Act requires TVA to charge rates for power that will produce gross revenues sufficient to provide funds for operation, maintenance, and administration of its power system; payments to states and counties in lieu of taxes ("tax equivalents"); debt service on outstanding indebtedness; payments to the U.S. Treasury in repayment of and as a return on the Power Program Appropriation Investment; and such additional margin as the TVA Board may consider desirable for investment in power system assets, retirement of outstanding Bonds in advance of maturity, additional reduction of the Power Program Appropriation Investment, and other purposes connected with TVA's power business.  TVA fulfilled its requirement to repay $1.0 billion of the Power Program Appropriation Investment with the 2014 payment; therefore, this repayment obligation is no longer a component of rate setting. In setting TVA's rates, the TVA Board is charged by the TVA Act to have due regard for the primary objectives of the TVA Act, including the objective that power shall be sold at rates as low as are feasible.  Rates set by the TVA Board are not subject to review or approval by any state or other federal regulatory body.
Fiscal Year
Fiscal Year

TVA's fiscal year ends September 30.  Years (2022, 2021, etc.) refer to TVA's fiscal years unless they are preceded by "CY," in which case the references are to calendar years.
Cost-Based Regulation
Cost-Based Regulation

Since the TVA Board is authorized by the TVA Act to set rates for power sold to its customers, TVA is self-regulated. Additionally, TVA's regulated rates are designed to recover its costs.  Based on current projections, TVA believes that rates, set at levels that will recover TVA's costs, can be charged and collected.  As a result of these factors, TVA records certain assets and liabilities that result from the regulated ratemaking process that would not be recorded under GAAP for non-regulated entities.   Regulatory assets generally represent incurred costs that have been deferred because such costs are probable of future recovery in customer rates.  Regulatory liabilities generally represent obligations to make refunds to customers for previous collections for costs that are not likely to be incurred or deferral of gains that will be credited to customers in future periods.  TVA assesses whether the regulatory assets are probable of future recovery by considering factors such as applicable regulatory changes, potential legislation, and changes in technology.  Based on these assessments, TVA believes the existing regulatory assets are probable of recovery.  This determination reflects the current regulatory and political environment and is subject to change in the future.  If future recovery of regulatory assets ceases to be probable, or TVA is no longer considered to be a regulated entity, then costs would be required to be written off.  All regulatory asset write offs would be required to be recognized in earnings in the period in which future recovery ceases to be probable.
Basis of Presentation Basis of Presentation    The accompanying consolidated financial statements, which have been prepared in accordance with GAAP, include the accounts of TVA and variable interest entities ("VIEs") of which TVA is the primary beneficiary. See Note 11 — Variable Interest Entities. Intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates
Use of Estimates

The preparation of financial statements requires TVA to estimate the effects of various matters that are inherently uncertain as of the date of the consolidated financial statements.  Although the consolidated financial statements are prepared in conformity with GAAP, TVA is required to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the amounts of revenues and expenses, reported during the reporting period.  Each of these estimates varies in regard to the level of judgment involved and its potential impact on TVA's financial results.  Estimates are considered critical either when a different estimate could have reasonably been used, or where changes in the estimate are reasonably likely to occur from period to period, and such use or change would materially impact TVA's financial condition, results of operations, or cash flows.
Reclassification, Comparability Adjustment
Cash and Cash Equivalents and Restricted Cash and Investments
Cash, Cash Equivalents, and Restricted Cash

    Cash includes cash on hand, non-interest bearing cash, and deposit accounts. All highly liquid investments with original maturities of three months or less are considered cash equivalents. Cash and cash equivalents that are restricted, as to withdrawal or use under the terms of certain contractual agreements, are recorded in Other long-term assets on the Consolidated Balance Sheets. Restricted cash and cash equivalents include cash held in trusts that are currently restricted for TVA economic development loans and for certain TVA environmental programs in accordance with agreements related to
compliance with certain environmental regulations. See Note 21 — Commitments and Contingencies — Legal Proceedings — Environmental Agreements.

    The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported on the Consolidated Balance Sheets and Consolidated Statements of Cash Flows:
Cash, Cash Equivalents, and Restricted Cash
At September 30
(in millions)
 20222021
Cash and cash equivalents$500 $499 
Restricted cash and cash equivalents included in Other long-term assets20 19 
Total cash, cash equivalents, and restricted cash$520 $518 
Allowance for Uncollectible Accounts
Allowance for Uncollectible Accounts

TVA recognizes an allowance that reflects the current estimate for credit losses expected to be incurred over the life of the financial assets based on historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amounts. The appropriateness of the allowance is evaluated at the end of each reporting period.

To determine the allowance for trade receivables, TVA considers historical experience and other currently available information, including events such as customer bankruptcy and/or a customer failing to fulfill payment arrangements by the due date. TVA's corporate credit department also performs an assessment of the financial condition of customers and the credit quality of the receivables. In addition, TVA reviews other reasonable and supportable forecasts to determine if the allowance for uncollectible amounts should be further adjusted in accordance with the accounting guidance for Current Expected Credit Losses.

To determine the allowance for loans receivables, TVA aggregates loans into the appropriate pools based on the existence of similar risk characteristics such as collateral types and internal assessed credit risks. In situations where a loan exhibits unique risk characteristics and is no longer expected to experience similar risks to the rest of its pool, the loan will be evaluated separately. TVA derives an annual loss rate based on historical loss and then adjusts the rate to reflect TVA's consideration of available information on current conditions and reasonable and supportable future forecasts. This information may include economic and business conditions, default trends, and other internal and external factors. For periods beyond the reasonable and supportable forecast period, TVA uses the current calculated long-term average historical loss rate for the remaining life of the loan portfolio.
The allowance for uncollectible accounts was less than $1 million at both September 30, 2022 and 2021, for trade accounts receivable.  Additionally, loans receivable of $105 million and $99 million at September 30, 2022 and 2021, respectively, are included in Accounts receivable, net and Other long-term assets, for the current and long-term portions, respectively. Loans receivables are reported net of allowances for uncollectible accounts of $3 million and $4 million at September 30, 2022 and 2021, respectively.
Revenues
Revenues

TVA recognizes revenue from contracts with customers to depict the transfer of goods or services to customers in an amount to which the entity expects to be entitled in exchange for those goods or services. For the generation and transmission of electricity, this is generally at the time the power is delivered to a metered customer delivery point for the customer's consumption or distribution. As a result, revenues from power sales are recorded as electricity is delivered to customers. In addition to power sales invoiced and recorded during the month, TVA accrues estimated unbilled revenues for power sales provided to five customers whose billing date occurs prior to the end of the month.  Exchange power sales are presented in the accompanying Consolidated Statements of Operations as a component of sales of electricity. Exchange power sales are sales of excess power after meeting TVA native load and directly served requirements.  Native load refers to the customers on whose behalf a company, by statute, franchise, regulatory requirement, or contract, has undertaken an obligation to serve. TVA engages in other arrangements in addition to power sales. Certain other revenue from activities related to TVA's overall mission is recorded in Other revenue. Revenues that are not related to the overall mission are recorded in Other income, net.
Inventories
Inventories

Certain Fuel, Materials, and Supplies.  Materials and supplies inventories are valued using an average unit cost method. A new average cost is computed after each inventory purchase transaction, and inventory issuances are priced at the latest moving weighted average unit cost. Coal, fuel oil, and natural gas inventories are valued using an average cost method. A new weighted average cost is computed monthly, and monthly issues are priced accordingly.
Renewable Energy Certificates. TVA accounts for Renewable Energy Certificates ("RECs") using the specific identification cost method. RECs that are acquired through power purchases are recorded as inventory and charged to purchased power expense when the RECs are subsequently used or sold. TVA assigns a value to the RECs at the inception of the power purchase arrangement using a relative standalone selling price approach. RECs created through TVA-owned asset generation are recorded at zero cost.

Emission Allowances.  TVA accounts for emission allowances using the specific identification cost method. Allowances that are acquired through third party purchases are recorded as inventory at cost and charged to operating expense based on tons emitted during the respective compliance periods.  

Allowance for Inventory Obsolescence.  TVA reviews materials and supplies inventories by category and usage on a periodic basis.  Each category is assigned a probability of becoming obsolete based on the type of material and historical usage data.  TVA has a fleet-wide inventory management policy for each generation type. Based on the estimated value of the inventory, TVA adjusts its allowance for inventory obsolescence.
Property, Plant, and Equipment, and Depreciation
Property, Plant, and Equipment, and Depreciation

    Property, Plant, and Equipment. Additions to plant are recorded at cost, which includes direct and indirect costs.  The cost of current repairs and minor replacements is charged to operating expense.  Nuclear fuel, which is included in Property, plant, and equipment, is valued using the average cost method for raw materials and the specific identification method for nuclear fuel in a reactor.  Amortization of nuclear fuel in a reactor is calculated on a units-of-production basis and is included in fuel expense. When property, plant, and equipment is retired, accumulated depreciation is charged for the original cost of the assets. Gains or losses are only recognized upon the sale of land or an entire operating unit. TVA capitalizes certain costs incurred in connection with developing or obtaining internal-use software. Capitalized software costs are included in Property, plant, and equipment on the Consolidated Balance Sheets and are generally amortized over seven years.  

    Depreciation. TVA accounts for depreciation of its properties using the composite depreciation convention of accounting.  Under the composite method, assets with similar economic characteristics are grouped and depreciated as one asset. Depreciation is generally computed on a straight-line basis over the estimated service lives of the various classes of assets. The estimation of asset useful lives requires management judgment, supported by external depreciation studies of historical asset retirement experience. Depreciation rates are determined based on external depreciation studies that are updated approximately every five years. During the first quarter of 2022, TVA implemented a new depreciation study related to its completed plant.  The new study included a decline in the service life estimates of TVA’s coal-fired plants based on current planning assumptions to potentially retire the remainder of the coal-fired fleet by 2035. Implementation of the study resulted in an estimated increase to depreciation and amortization expense of approximately $345 million during 2022. This estimate represents the effect of using the new depreciation rates on the property, plant, and equipment balances at September 30, 2021, and does not include any potential impact from additions to or retirements of net completed plant, that occurred since September 30, 2021.

Depreciation expense for the years ended September 30, 2022, 2021, and 2020 was $1.8 billion, $1.4 billion, and $1.6 billion, respectively. Depreciation expense expressed as a percentage of the average annual depreciable completed plant was 2.98 percent for 2022, 2.28 percent for 2021, and 2.74 percent for 2020.  Average depreciation rates by asset class are as follows:
Property, Plant, and Equipment Depreciation Rates
At September 30
(percent)
202220212020
Asset Class
Nuclear2.72 2.38 2.38 
Coal-fired(1)
4.27 1.95 3.62 
Hydroelectric1.85 1.60 1.60 
Gas and oil-fired3.38 2.98 3.04 
Transmission1.51 1.34 1.34 
Other3.64 7.12 7.26 
Note
(1) The rates include the acceleration of depreciation related to retiring certain coal-fired units and potentially retiring the remainder of the coal-fired fleet by 2035. See Note 7 — Plant Closures.

Reacquired Rights. Property, plant, and equipment includes intangible reacquired rights, net of amortization, of $178 million and $184 million as of September 30, 2022 and 2021, respectively, related to the purchase of residual interests from lease/leaseback agreements of certain combustion turbine units ("CTs"). Reacquired rights are amortized over the estimated useful lives of the underlying CTs which range from 33 to 35 years. Amortization expense was $6 million for 2022 and $8 million for the years 2021 and 2020, and accumulated amortization at September 30, 2022 and 2021 totaled $42 million and $36 million,
respectively. At September 30, 2022, the estimated aggregate amortization expense (in millions) for each of the next five years and thereafter is shown below:

 20232024202520262027Thereafter
Reacquired Rights$6 $6 $6 $6 $6 $148 
Impairment of Assets.  TVA evaluates long-lived assets for impairment when events or changes in circumstances indicate that the carrying value of such assets may not be recoverable.  For long-lived assets, TVA bases its evaluation on impairment indicators such as the nature of the assets, the future economic benefit of the assets, any historical or future profitability measurements, regulatory approval and ability to set rates at levels that allow for recoverability of the assets, and other external market conditions or factors that may be present.  If such impairment indicators are present or other factors exist that indicate that the carrying amount of an asset may not be recoverable, TVA determines whether an impairment has occurred based on an estimate of undiscounted cash flows attributable to the asset as compared with the carrying value of the asset.  If an impairment has occurred, the amount of the impairment recognized is measured as the excess of the asset's carrying value over its fair value.  Additionally, TVA regularly evaluates construction projects.  If the project is canceled or deemed to have no future economic benefit, the project is written off as an asset impairment or, upon TVA Board approval, reclassified as a regulatory asset and amortized over the Board-approved period. See Note 7 — Plant Closures.
Lessee, Leases
Leases

    TVA recognizes a lease asset and lease liability for leases with terms of greater than 12 months. Lease assets represent TVA's right to use an underlying asset for the lease term, and lease liabilities represent TVA's obligation to make lease payments arising from the lease, both of which are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date.  TVA has certain lease agreements that include variable lease payments that are based on energy production levels. These variable lease payments are not included in the measurement of the lease assets or lease liabilities but are recognized in the period in which the expenses are incurred.
    
    While not specifically structured as leases, certain power purchase agreements ("PPAs") are deemed to contain a lease of the underlying generating units when the terms convey the right to control the use of the assets. Amounts recorded for these leases are generally based on the amount of the scheduled capacity payments due over the remaining terms of the PPAs, the terms of which vary. The total lease obligations included in Accounts payable and accrued liabilities and Other long-term liabilities and Finance lease liabilities related to these agreements were $425 million and $133 million for finance and operating leases, respectively, at September 30, 2022. The total lease obligations included in Accounts payable and accrued liabilities and Other long-term liabilities and Finance lease liabilities related to these agreements were $464 million and $143 million for finance and operating leases, respectively, at September 30, 2021.

    TVA has agreements with lease and non-lease components and has elected to account for the components separately. Consideration is allocated to lease and non-lease components generally based on relative standalone selling prices.

    TVA has lease agreements which include options for renewal and early termination. The intent to renew a lease varies depending on the lease type and asset. Renewal options that are reasonably certain to be exercised are included in the lease measurements. The decision to terminate a lease early is dependent on various economic factors. No termination options have been included in TVA's lease measurements.
    
    Leases with an initial term of 12 months or less, which do not include an option to extend the initial term of the lease to greater than 12 months that TVA is reasonably certain to exercise, are not recorded on the Consolidated Balance Sheets at September 30, 2022.
    Operating leases are recognized on a straight-line basis over the term of the lease agreement. Rent expense associated with short-term leases and variable leases is recorded in Operating and maintenance expense, Fuel expense, or Purchased power expense on the Consolidated Statements of Operations. Expenses associated with finance leases result in the separate presentation of interest expense on the lease liability and amortization expense of the related lease asset on the Consolidated Statements of Operations.
Decommissioning Costs
Decommissioning Costs

    TVA recognizes legal obligations associated with the future retirement of certain tangible long-lived assets.  These obligations relate to fossil fuel-fired generating plants, nuclear generating plants, hydroelectric generating plants/dams, transmission structures, and other property-related assets.  Activities involved with retiring these assets could include decontamination and demolition of structures, removal and disposal of wastes, and site restoration. Revisions to the forecasted costs of decommissioning activities are made whenever factors indicate that the timing or amounts of estimated cash flows have changed materially. Studies are updated for both nuclear and non-nuclear decommissioning costs at least every five years.  Any accretion or depreciation expense related to these liabilities and assets is charged to a regulatory asset.  See Note 10 — Regulatory Assets and Liabilities — Nuclear Decommissioning Costs and Non-Nuclear Decommissioning Costs and Note 13 —
Asset Retirement Obligations.
Down-blend Offering for Tritium
Down-blend Offering for Tritium

TVA, the U.S. Department of Energy ("DOE"), and certain nuclear fuel contractors have entered into agreements, referred to as the Down-blend Offering for Tritium ("DBOT"), that provide for the production, processing, and storage of low-enriched uranium that is to be made using surplus DOE highly enriched uranium and other uranium.  Low-enriched uranium can be fabricated into fuel for use in a nuclear power plant.  Production of the low-enriched uranium began in 2019 and is contracted to continue through September 2025. Contract activity will consist of storage and flag management.  Flag management ensures that the uranium is of U.S. origin, free from foreign obligations, and unencumbered by policy restrictions, so that it can be used in connection with the production of tritium. Under the terms of the interagency agreement between the DOE and TVA, the DOE will reimburse TVA for a portion of the costs of converting the highly enriched uranium to low-enriched uranium. Since 2019, TVA has received $188 million in reimbursements from the DOE. At September 30, 2022, TVA recorded $9 million in Accounts receivable, net related to this agreement.
Investment Funds
Investment Funds

    Investment funds consist primarily of trust funds designated to fund decommissioning requirements (see Note 21 — Commitments and Contingencies — Decommissioning Costs), the Supplemental Executive Retirement Plan ("SERP") (see Note 20 — Benefit Plans — Overview of Plans and Benefits — Supplemental Executive Retirement Plan), and the Deferred Compensation Plan ("DCP"). The Nuclear Decommissioning Trust ("NDT") holds funds primarily for the ultimate decommissioning of TVA's nuclear power plants. The Asset Retirement Trust ("ART") holds funds primarily for the costs related to the future closure and retirement of TVA's other long-lived assets. The NDT, ART, SERP, and DCP funds are invested in portfolios of securities generally designed to achieve a return in line with overall equity and debt market performance. The NDT, ART, SERP, and DCP funds are all classified as trading.
Insurance
Insurance

Although TVA uses private companies to administer its healthcare plans for eligible active and retired employees not covered by Medicare, TVA does not purchase health insurance.  Third-party actuarial specialists assist TVA in determining certain liabilities for self-insured claims.  TVA recovers the costs of claims through power rates and through adjustments to the participants' contributions to their benefit plans.  These liabilities are included in Other long-term liabilities on the Consolidated Balance Sheets.

The Federal Employees' Compensation Act ("FECA") governs liability to employees for service-connected injuries.  TVA purchases excess workers' compensation insurance above a self-insured retention.

    In addition to excess workers' compensation insurance, TVA purchases property and liability insurance for nuclear assets and operations. See Note 21 — Commitments and Contingencies — Nuclear Insurance. TVA also purchases liability insurance and property insurance for certain conventional (non-nuclear) assets, and other insurance policies when commercially feasible.
    The insurance policies are subject to the terms and conditions of the specific policy, including deductibles or self-insured retentions. To the extent insurance would not provide either a partial or total recovery of the costs associated with a loss, TVA would have to recover any such costs through other means, including through power rates.
Research and Development Costs
Research and Development Costs

Research and development costs are expensed when incurred.  TVA's research programs include those related to power delivery technologies, emerging technologies (clean energy, renewables, distributed resources, and energy efficiency), technologies related to generation (fossil fuel, nuclear, and hydroelectric), and environmental technologies.
Tax Equivalents
Tax Equivalents

TVA is not subject to federal income taxation. In addition, neither TVA nor its property, franchises, or income is subject to taxation by states or their subdivisions. The TVA Act requires TVA to make payments to states and counties in which TVA conducts its power operations and in which TVA has acquired power properties previously subject to state and local taxation.   The total amount of these payments is five percent of gross revenues from sales of power during the preceding year, excluding sales or deliveries to other federal agencies and off-system sales with other utilities, with a provision for minimum payments under certain circumstances. TVA calculates tax equivalent expense by subtracting the prior year fuel cost-related tax equivalent regulatory asset or liability from the payments made to the states and counties during the current year and adding back the current year fuel cost-related tax equivalent regulatory asset or liability. Fuel cost-related tax equivalent expense is recognized in the same accounting period in which the fuel cost-related revenue is recognized.
Maintenance Costs Maintenance CostsTVA records maintenance costs and repairs related to its property, plant, and equipment on the Consolidated Statements of Operations as they are incurred except for the recording of certain regulatory assets for retirement and removal costs.
v3.22.2.2
Variable Interest Entities (Policies)
 12 Months Ended
Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Summary of Impact of VIEs on Consolidated Balance Sheets The financial statement items attributable to carrying amounts and classifications of JSCCG, Holdco, and SCCG as of September 30, 2022 and 2021, as reflected on the Consolidated Balance Sheets, are as follows:
Summary of Impact of VIEs on Consolidated Balance Sheets
At September 30
(in millions)
 20222021
Current liabilities 
Accrued interest$10 $10 
Accounts payable and accrued liabilities2 3 
Current maturities of long-term debt of variable interest entities39 43 
Total current liabilities
51 56 
Other liabilities
Other long-term liabilities18 20 
Long-term debt, net
Long-term debt of variable interest entities, net968 1,006 
Total liabilities$1,037 $1,082 
Consolidation, Variable Interest Entity, Policy A VIE is an entity that either (i) has insufficient equity to permit the entity to finance its activities without additional subordinated financial support or (ii) has equity investors who lack the characteristics of owning a controlling financial interest. When TVA determines that it has a variable interest in a VIE, a qualitative evaluation is performed to assess which interest holders have the power to direct the activities that most significantly impact the economic performance of the entity and have the obligation to absorb losses or receive benefits that could be significant to the entity. The evaluation considers the purpose and design of the business, the risks that the business was designed to create and pass along to other entities, the activities of the business that can be directed and which party can direct them, and the expected relative impact of those activities on the economic performance of the business through its life. TVA has the power to direct the activities of an entity when it has the ability to make key operating and financing decisions, including, but not limited to, capital investment and the issuance of debt. Based on the evaluation of these criteria, TVA has determined it is the primary beneficiary of certain entities and as such is required to account for the VIEs on a consolidated basis.
v3.22.2.2
Asset Retirement Obligations Asset Retirement Obligations (Policies)
 12 Months Ended
Sep. 30, 2022
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligations, Policy
Decommissioning Costs

    TVA recognizes legal obligations associated with the future retirement of certain tangible long-lived assets.  These obligations relate to fossil fuel-fired generating plants, nuclear generating plants, hydroelectric generating plants/dams, transmission structures, and other property-related assets.  Activities involved with retiring these assets could include decontamination and demolition of structures, removal and disposal of wastes, and site restoration. Revisions to the forecasted costs of decommissioning activities are made whenever factors indicate that the timing or amounts of estimated cash flows have changed materially. Studies are updated for both nuclear and non-nuclear decommissioning costs at least every five years.  Any accretion or depreciation expense related to these liabilities and assets is charged to a regulatory asset.  See Note 10 — Regulatory Assets and Liabilities — Nuclear Decommissioning Costs and Non-Nuclear Decommissioning Costs and Note 13 —
Asset Retirement Obligations.
v3.22.2.2
Benefit Plans Benefit Plans (Policies)
 12 Months Ended
Sep. 30, 2022
Retirement Benefits [Abstract]  
Benefit Plans
Accounting Mechanisms

Regulatory Accounting.  TVA has classified all amounts related to unrecognized prior service costs/(credits), net actuarial gains or losses, and the funded status as regulatory assets or liabilities as such amounts are probable of collection in
future rates. Additionally, TVA recognizes pension costs as regulatory assets or regulatory liabilities to the extent that the amount calculated under U.S. GAAP as pension expense differs from the amount TVA contributes to the pension plan as pension plan contributions. As a result of plan design changes, future contributions are expected to exceed the expense calculated under U.S. GAAP. Accordingly, TVA will discontinue this regulatory accounting practice once all such deferred costs have been recovered, at which time it will recognize pension costs in accordance with U.S. GAAP.

Cost Method. TVA uses the projected unit credit cost method to determine the service cost and the projected benefit obligation for retirement, termination, and ancillary benefits.  Under this method, a "projected accrued benefit" is calculated at the beginning of the year and at the end of the year for each benefit that may be payable in the future.  The "projected accrued benefit" is based on the plan's accrual formula and upon service at the beginning or end of the year, but it uses final average compensation, social security benefits, and other relevant factors projected to the age at which the employee is assumed to leave active service.  The projected benefit obligation is the actuarial present value of the "projected accrued benefits" at the beginning of the year for employed participants and is the actuarial present value of all benefits for other participants.  The service cost is the actuarial present value of the difference between the "projected accrued benefits" at the beginning and end of the year.

Amortization of Net Gain or Loss.  TVA utilizes the corridor approach for gain/loss amortization.  Differences between actuarial assumptions and actual plan results are deferred and amortized into periodic cost only when the accumulated differences exceed 10 percent of the greater of the projected benefit obligation or the market-related value of plan assets.  If necessary, the excess is amortized over the average future expected working lifetime of participants expected to receive benefits, which is approximately 11 years for the pension plan.

Amortization of Prior Service Cost/(Credit). Amortization of net prior service cost/(credit) resulting from a plan change is included as a component of period expense in the year first recognized and every year thereafter until it is fully amortized.  The increase or decrease in the benefit obligation due to the plan change is amortized over the average remaining service period of participating employees expected to receive benefits under the plan. The pension and post-retirement plans currently have prior service costs/(credits) from plan changes made in 2016, 2018, 2019, 2020, and 2021 with remaining amortization periods ranging from one to seven years. However, when a plan change reduces the benefit obligation, existing positive prior service costs are reduced or eliminated starting with the earliest established before a new prior service credit base is established.

Asset Method.  TVA's asset method calculates a market-related value of assets ("MRVA") that recognizes realized and unrealized investment gains and losses over a three-year smoothing period to decrease the volatility of annual net periodic pension benefit costs. The MRVA is used to determine the expected return on plan assets, a component of net periodic pension benefit cost. The difference in the expected return on the MRVA and the actual return on the fair value on plan assets is recognized as an actuarial (gain)/loss in the pension benefit obligation at September 30. However, the MRVA has no impact on the fair value of plan assets measured at September 30.
v3.22.2.2
Revenue (Policies)
 12 Months Ended
Sep. 30, 2022
Revenue from Contract with Customer [Abstract]  
Revenues
Revenues

TVA recognizes revenue from contracts with customers to depict the transfer of goods or services to customers in an amount to which the entity expects to be entitled in exchange for those goods or services. For the generation and transmission of electricity, this is generally at the time the power is delivered to a metered customer delivery point for the customer's consumption or distribution. As a result, revenues from power sales are recorded as electricity is delivered to customers. In addition to power sales invoiced and recorded during the month, TVA accrues estimated unbilled revenues for power sales provided to five customers whose billing date occurs prior to the end of the month.  Exchange power sales are presented in the accompanying Consolidated Statements of Operations as a component of sales of electricity. Exchange power sales are sales of excess power after meeting TVA native load and directly served requirements.  Native load refers to the customers on whose behalf a company, by statute, franchise, regulatory requirement, or contract, has undertaken an obligation to serve. TVA engages in other arrangements in addition to power sales. Certain other revenue from activities related to TVA's overall mission is recorded in Other revenue. Revenues that are not related to the overall mission are recorded in Other income, net.
v3.22.2.2
Plant Closures (Policies)
 12 Months Ended
Sep. 30, 2022
Property, Plant and Equipment [Abstract]  
Plant Retirement and Abandonment, Policy [Policy Text Block]
Financial Impact

TVA's policy is to adjust depreciation rates to reflect the most current assumptions, ensuring units will be fully depreciated by the applicable retirement dates. As a result of TVA's decision to accelerate the retirement of Bull Run, TVA has recognized a cumulative $482 million of accelerated depreciation since the second quarter of 2019. Of this amount, $140 million, $136 million, and $125 million were recognized for the years ended September 30, 2022, 2021, and 2020, respectively.

In addition, service lives for Cumberland Fossil Plant ("Cumberland"), Gallatin Fossil Plant ("Gallatin"), Kingston Fossil Plant ("Kingston"), and Shawnee Fossil Plant ("Shawnee") were shortened in a new depreciation study implemented during the first quarter of 2022 to reflect current planning assumptions to potentially retire the remainder of the coal-fired fleet by 2035. As a result, TVA recognized an estimated $339 million of additional depreciation related to these four coal-fired plants during the year ended September 30, 2022. This estimate represents the effect of using the new depreciation rates on the property, plant, and equipment balances at September 30, 2021, and does not include any potential impact from additions to or retirements of net completed plant, that occurred since September 30, 2021.

For the years ended September 30, 2022, 2021, and 2020, respectively, TVA also recognized $22 million, $4 million, and $13 million in Operating and maintenance expense related to additional inventory reserves and project write-offs for the coal-fired fleet, including Bull Run.
v3.22.2.2
Summary of Significant Accounting Policies [Table Text Block]
 12 Months Ended
Sep. 30, 2022
Accounting Policies [Abstract]  
Property, Plant, and Equipment Depreciation Rates Average depreciation rates by asset class are as follows:
Property, Plant, and Equipment Depreciation Rates
At September 30
(percent)
202220212020
Asset Class
Nuclear2.72 2.38 2.38 
Coal-fired(1)
4.27 1.95 3.62 
Hydroelectric1.85 1.60 1.60 
Gas and oil-fired3.38 2.98 3.04 
Transmission1.51 1.34 1.34 
Other3.64 7.12 7.26 
v3.22.2.2
Accounts Receivable, Net Accounts Receivable, Net (Tables)
 12 Months Ended
Sep. 30, 2022
Accounts Receivable, after Allowance for Credit Loss [Abstract]  
Accounts Receivable, Net
Accounts receivable primarily consist of amounts due from customers for power sales.  The table below summarizes the types and amounts of TVA's accounts receivable:
Accounts Receivable, Net
At September 30
(in millions)
 20222021
Power receivables$1,899 $1,480 
Other receivables108 86 
Accounts receivable, net(1)
$2,007 $1,566 
v3.22.2.2
Inventories, Net Inventories, Net (Tables)
 12 Months Ended
Sep. 30, 2022
Inventory, Net [Abstract]  
Inventories, Net
The table below summarizes the types and amounts of TVA's inventories:
Inventories, Net 
At September 30
(in millions)
 20222021
Materials and supplies inventory$808 $775 
Fuel inventory303 198 
Renewable energy certificates/emissions allowance inventory, net18 12 
Allowance for inventory obsolescence(57)(35)
Inventories, net$1,072 $950 
Fuel inventory increased $105 million at September 30, 2022, as compared to September 30, 2021, primarily due to an increase in coal inventory of $58 million and an increase in natural gas inventory of $32 million. Coal inventory increased primarily due to higher costs of fuel, including transportation costs, as a result of continued supply constraints driven by both domestic and export demand, limited production capacity, and market volatility. Coal inventory also increased over the prior year due to coal conservation efforts and an increase in inventory levels as TVA prepares for winter inventory needs. Natural gas inventory increased primarily due to higher gas prices, as well as an increase in the amount of stored gas to mitigate fuel price volatility.
v3.22.2.2
Net Completed Plant Net Completed Plant (Tables)
 12 Months Ended
Sep. 30, 2022
Property, Plant and Equipment, Net, by Type [Abstract]  
Net Completed Plant
Net completed plant consisted of the following:
Net Completed Plant
At September 30
(in millions)
 20222021
 CostAccumulated Depreciation 
Net		CostAccumulated DepreciationNet
Coal-fired(1)
$18,145 $13,649 $4,496 $19,319 $14,357 $4,962 
Gas and oil-fired6,112 1,957 4,155 6,076 1,824 4,252 
Nuclear26,629 12,928 13,701 26,024 12,632 13,392 
Transmission8,919 3,301 5,618 8,597 3,215 5,382 
Hydroelectric3,987 1,192 2,795 3,525 1,135 2,390 
Other electrical plant1,724 807 917 1,943 1,103 840 
Multipurpose dams900 396 504 900 388 512 
Other stewardship26 9 17 27 9 18 
Total$66,442 $34,239 $32,203 $66,411 $34,663 $31,748 
v3.22.2.2
Other Long-Term Assets (Tables)
 12 Months Ended
Sep. 30, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]  
Other Long-Term Assets
The table below summarizes the types and amounts of TVA's other long-term assets:
Other Long-Term Assets 
At September 30
(in millions)
 20222021
Loans and other long-term receivables, net$99 $96 
EnergyRight® receivables, net
49 57 
Prepaid long-term service agreements74 44 
Commodity contract derivative assets102 40 
Other70 83 
Total other long-term assets$394 $320 
v3.22.2.2
Regulatory Assets and Liabilities Regulatory Assets and Liabilities (Tables)
 12 Months Ended
Sep. 30, 2022
Regulatory Assets and Liabilities Disclosure [Abstract]  
Regulatory Assets and Liabilities Components of regulatory assets and regulatory liabilities are summarized in the table below. 
Regulatory Assets and Liabilities 
At September 30
(in millions)
 20222021
Current regulatory assets  
Unrealized losses on interest rate derivatives$47 $114 
Unrealized losses on commodity derivatives14 3 
Fuel cost adjustment receivable77 79 
Total current regulatory assets138 196 
Non-current regulatory assets  
Retirement benefit plans deferred costs1,839 3,668 
Non-nuclear decommissioning costs2,856 2,653 
Unrealized losses on interest rate derivatives479 1,122 
Nuclear decommissioning costs821 363 
Unrealized losses on commodity derivatives1 — 
Other non-current regulatory assets138 150 
Total non-current regulatory assets6,134 7,956 
Total regulatory assets$6,272 $8,152 
Current regulatory liabilities  
Fuel cost adjustment tax equivalents$218 $130 
Unrealized gains on commodity derivatives173 210 
Total current regulatory liabilities391 340 
Non-current regulatory liabilities  
Retirement benefit plans deferred credits70 — 
Unrealized gains on commodity derivatives102 40 
Total non-current regulatory liabilities172 40 
Total regulatory liabilities$563 $380 
v3.22.2.2
Asset Retirement Obligations Asset Retirement Obligations (Tables)
 12 Months Ended
Sep. 30, 2022
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligation Activity
Asset Retirement Obligation Activity
(in millions)
 NuclearNon-NuclearTotal
Balance at September 30, 2020$3,278 $3,507 $6,785 
Settlements(11)(231)(242)
Revisions in estimate12 191 203 
Additional obligations— 43 43 
Accretion (recorded as regulatory asset)149 64 213 
Balance at September 30, 20213,428 3,574 7,002 
(1)
Settlements(2)(309)(311)
(2)
Revisions in estimate61 186 247 
Accretion (recorded as regulatory asset)156 68 224 
Balance at September 30, 2022$3,643 $3,519 $7,162 
(1)
Note
(1) Includes $275 million and $266 million at September 30, 2022 and 2021, respectively, in Current liabilities.
(2) Settlements include the change in asset retirement obligation project accruals included in Accounts payable and accrued liabilities of $20 million.
v3.22.2.2
Other Long-Term Liabilities Other Long-Term Liabilities (Tables)
 12 Months Ended
Sep. 30, 2022
Other Liabilities, Noncurrent [Abstract]  
Other Long-Term Liabilities
Other Long-Term Liabilities
At September 30
(in millions)
 2022
2021(1)
Interest rate swap liabilities$851 $1,524 
Operating lease liabilities93 122 
Currency swap liabilities228 76 
EnergyRight® financing obligation58 66 
Long-term deferred compensation39 42 
Advances for construction53 24 
Long-term deferred revenue39 37 
Accrued long-term service agreements— 29 
Other124 121 
Total other long-term liabilities$1,485 $2,041 
Note
(1) At September 30, 2021, $5 million and $19 million previously classified as Long-term deferred revenue (a component of Other long-term liabilities) and Other (a
component of Other long-term liabilities), respectively, were reclassified to Advances for construction (a component of Other long-term liabilities) to conform
with current year presentation.
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations (Tables)
 12 Months Ended
Sep. 30, 2022
Debt and Other Obligations [Abstract]  
Schedule of short-term borrowings The following table provides information regarding TVA's short-term borrowings:
Short-term Borrowings
At September 30
 20222021
Gross amount outstanding - discount notes (in millions)$1,173 $780 
Weighted average interest rate - discount notes2.93 %0.03 %
Debt Securities Activity
The table below summarizes the long-term debt securities activity for the years ended September 30, 2022 and 2021.
Debt Securities Activity
For the years ended September 30
(in millions)
 20222021
Issues
2021 Series A(1)
$— $500 
2022 Series A(2)
500 — 
Discount on debt issues(16)— 
Total$484 $500 
Redemptions/Maturities(3)
 
2009 Series B$28 $29 
2011 Series A— 1,500 
1998 Series H— 331 
2012 Series A1,000 — 
Total redemptions/maturities of power bonds1,028 1,860 
Debt of variable interest entities43 41 
Total redemptions/maturities of debt$1,071 $1,901 
Notes
(1) The 2021 Series A Bonds were issued at 99.982 percent of par.
(2) The 2022 Series A Bonds were issued at 96.786 percent of par.
(3) All redemptions were at 100 percent of par.
Debt Outstanding Total debt outstanding at September 30, 2022 and 2021, consisted of the following: 
Short-Term Debt
At September 30
(in millions)
 
CUSIP or Other Identifier
 
Maturity
 
Coupon Rate		20222021
Short-term debt, net of discounts$1,172 $780 
Current maturities of long-term debt of VIEs issued at par39 43 
Current maturities of power bonds issued at par
880591EN88/15/20221.875%— 1,000 
880591EF512/15/20223.770%1 1 
880591EF56/15/20233.770%28 27 
Total current maturities of power bonds issued at par  29 1,028 
Total current debt outstanding, net  $1,240 $1,851 
Long-Term Debt
At September 30
(in millions)
 
CUSIP or Other Identifier
 
Maturity
Coupon
Rate		2022 Par2021 ParStock Exchange Listings
880591ER99/15/20242.875%$1,000 $1,000 New York
880591EW85/15/20250.750%1,000 1,000 New York
880591CJ911/1/20256.750%1,350 1,350 New York, Hong Kong, Luxembourg, Singapore
880591EU22/1/20272.875%1,000 1,000 New York
880591300(3)
6/1/20282.134%256 256 New York
880591409(3)
5/1/20292.216%208 208 New York
880591DM15/1/20307.125%1,000 1,000 New York, Luxembourg
880591EX69/15/20311.500%500 500 New York
880591DP46/7/20326.587%
(2)
279 
(1)
337 
(1)
New York, Luxembourg
880591DV17/15/20334.700%472 472 New York, Luxembourg
880591EF56/15/20343.770%160 190 None
880591DX76/15/20354.650%436 436 New York
880591CK64/1/20365.980%121 121 New York
880591CS94/1/20365.880%1,500 1,500 New York
880591CP51/15/20386.150%1,000 1,000 New York
880591ED06/15/20385.500%500 500 New York
880591EH19/15/20395.250%2,000 2,000 New York
880591EP312/15/20423.500%1,000 1,000 New York
880591DU36/7/20434.962%
(2)
168 
(1)
202 
(1)
New York, Luxembourg
880591EB41/15/20484.875%500 500 New York, Luxembourg
880591DZ24/1/20565.375%1,000 1,000 New York
880591EJ79/15/20604.625%1,000 1,000 New York
880591ES79/15/20654.250%1,000 1,000 New York
880591EY49/15/20524.250%500 — New York
Subtotal17,950 17,572  
Unamortized discounts, premiums, issue costs, and other (124)(115) 
Total long-term outstanding power bonds, net 17,826 17,457  
Long-term debt of VIEs, net968 1,006 
Total long-term debt, net$18,794 $18,463 
Notes
(1)  Includes net exchange gain from currency transactions of $150 million and $58 million at September 30, 2022 and 2021, respectively.
(2)  The coupon rate represents TVA's effective interest rate.
(3)  TVA PARRS, CUSIP numbers 880591300 and 880591409, may be redeemed under certain conditions.  See Put Options above.
Maturities Due in the Year Ending September 30
Maturities Due in the Year Ending September 30
(in millions)
 20232024202520262027ThereafterTotal
Long-term power bonds including current maturities(1)
$29 $1,022 $1,022 $1,370 $1,020 $13,666 $18,129 
Short-term debt(2)
1,173 — — — — — 1,173 
Notes
(1) Long-term power bonds does not include non-cash items of foreign currency exchange gain of $150 million, unamortized debt issue costs of $42 million, and net
discount on sale of Bonds of $82 million.
(2) Short-term debt does not include the non-cash item of discount on issuance of discount notes of $1 million.
Summary of Long-Term Credit Facilities
The following table provides additional information regarding TVA's funding available under the four long-term revolving credit facilities:
Summary of Long-Term Credit Facilities
At September 30, 2022
(in millions)
Maturity DateFacility LimitLetters of Credit OutstandingCash BorrowingsAvailability
 February 2024$150 $38 $— $112 
February 2025500 500 — — 
September 20261,000 99 — 901 
March 20271,000 67 — 933 
     Total$2,650 $704 $— $1,946 
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions (Tables)
 12 Months Ended
Sep. 30, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Summary of Derivative Instruments That Receive Hedge Accounting Treatment
The following tables summarize the accounting treatment that certain of TVA's financial derivative transactions receive:
Summary of Derivative Instruments That Receive Hedge Accounting Treatment (part 1) 
Amount of Mark-to-Market Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss)
For the years ended September 30
Derivatives in Cash Flow Hedging RelationshipObjective of Hedge TransactionAccounting for Derivative
Hedging Instrument		20222021
Currency swapsTo protect against changes in cash flows caused by changes in foreign currency exchange rates (exchange rate risk)Unrealized gains and losses are recorded in AOCI and reclassified to Interest expense to the extent they are offset by gains and losses on the hedged transaction$(157)$126 
Summary of Derivative Instruments That Receive Hedge Accounting Treatment (part 2)(1)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) to Interest Expense
For the years ended September 30
Derivatives in Cash Flow Hedging Relationship20222021
Currency swaps$(93)$97 
Note
(1) There were no amounts excluded from effectiveness testing for any of the periods presented. Based on forecasted foreign currency exchange rates, TVA expects to reclassify approximately $29 million of gains from AOCI to Interest expense within the next 12 months to offset amounts anticipated to be recorded in Interest expense related to the forecasted exchange loss on the debt.
Summary of Derivative Instruments That Do Not Receive Hedge Accounting Treatment
Summary of Derivative Instruments That Do Not Receive Hedge Accounting Treatment
Amount of Gain (Loss) Recognized in Income on Derivatives(1)
For the years ended September 30
 
Derivative TypeObjective of DerivativeAccounting for Derivative Instrument20222021
Interest rate swapsTo fix short-term debt variable rate to a fixed rate (interest rate risk)Mark-to-market gains and losses are recorded as regulatory liabilities and assets, respectively

Realized gains and losses are recognized in Interest expense when incurred during the settlement period and are presented in operating cash flow		$(103)$(115)
Commodity derivatives
under the FHP		To protect against fluctuations in market prices of purchased commodities (price risk)
Mark-to-market gains and losses are recorded as regulatory liabilities and assets, respectively

Realized gains and losses are recognized in Fuel expense or Purchased power expense as the contracts settle to match the delivery period of the underlying commodity(2)
47 — 
Notes
(1) All of TVA's derivative instruments that do not receive hedge accounting treatment have unrealized gains (losses) that would otherwise be recognized in income but instead are deferred as regulatory liabilities and assets. As such, there were no related gains (losses) recognized in income for these unrealized gains (losses) for the years ended September 30, 2022 and 2021.
(2) Of the amount recognized in 2022, $38 million and $9 million were reported in Fuel expense and Purchased power expense, respectively.
Fair Values of TVA Derivatives
Fair Values of TVA Derivatives
At September 30
 20222021
Derivatives That Receive Hedge Accounting Treatment:
 BalanceBalance Sheet PresentationBalanceBalance Sheet Presentation
Currency swaps    
£250 million Sterling
$(130)
Accounts payable and accrued liabilities $(7); Other long-term liabilities $(123)
$(36)
Accounts payable and accrued liabilities $(4); Other long-term liabilities $(32)
£150 million Sterling
(110)
Accounts payable and accrued liabilities $(5); Other long-term liabilities $(105)
(47)
Accounts payable and accrued liabilities $(3); Other long-term liabilities $(44)
Derivatives That Do Not Receive Hedge Accounting Treatment:
 BalanceBalance Sheet PresentationBalanceBalance Sheet Presentation
Interest rate swaps    
$1.0 billion notional
$(672)
Accounts payable and accrued liabilities $(9); Accrued interest $(33); Other long-term liabilities $(630)
$(1,182)
Accounts payable and
accrued liabilities $(44); Accrued interest $(37);
Other long-term liabilities
$(1,101)
$476 million notional
(233)
Accounts payable and accrued liabilities $(3); Accrued interest $(9); Other long-term liabilities $(221)
(455)
Accounts payable and
accrued liabilities $(22); Accrued interest $(10);
Other long-term liabilities
$(423)
$42 million notional(1)
— N/A(2)
Accounts payable and
accrued liabilities $(1); Accrued interest $(1)
Commodity contract derivatives 145 
Other current assets $118; Other long-term assets $34; Accounts payable and accrued liabilities $(6); Other long-term liabilities $(1)
247 
Other current assets $210; Other long-term assets $40; Accounts payable and accrued liabilities $(3)
Commodity derivatives under the FHP115 
Accounts receivable, net $1; Other current assets $54; Other long-term assets $68; Accounts payable and accrued liabilities $(8)
— N/A
Currency Swaps Outstanding TVA had the following currency swaps outstanding at September 30, 2022:
Currency Swaps Outstanding
Effective Date of Currency Swap ContractAssociated TVA Bond Issues Currency ExposureExpiration Date of SwapOverall Effective
Cost to TVA
2001£250 million20326.59%
2003£150 million20434.96%
Commodity Contract Derivatives
Commodity Contract Derivatives 
At September 30
 20222021
 
Number of Contracts
Notional AmountFair Value (MtM)
(in millions)		Number of ContractsNotional Amount
Fair Value (MtM)
(in millions)
Natural gas contract derivatives44296 million mmBtu$145 40263 million mmBtu$247 
Offsetting Assets and Liabilities The amounts of TVA's derivative instruments as reported on the Consolidated Balance Sheets are shown in the table below:
Derivative Assets and Liabilities(1)
At September 30
(in millions)
20222021
Assets
Commodity contract derivatives $152 $250 
Commodity derivatives under the FHP(2)
123 — 
Total derivatives subject to master netting or similar arrangement$275 $250 
Liabilities
Currency swaps$240 $83 
Interest rate swaps(3)
905 1,639 
Commodity contract derivatives7 3 
Commodity derivatives under the FHP(2)
8 — 
Total derivatives subject to master netting or similar arrangement$1,160 $1,725 
Notes
(1) Offsetting amounts include counterparty netting of derivative contracts. Except as discussed below, there were no other material offsetting amounts on TVA's Consolidated Balance Sheets at either September 30, 2022 or 2021.
(2) At September 30, 2022, the gross derivative asset and gross derivative liability was $168 million and $53 million, respectively, with offsetting amounts for each totaling $45 million. TVA received $68 million of collateral from counterparties as of September 30, 2022, which is recorded separately from the fair values of the derivative assets and liabilities and reported in Accounts payable and accrued liabilities.
(3) Letters of credit of approximately $704 million and $1.2 billion were posted as collateral at September 30, 2022 and 2021, respectively, to partially secure the liability positions of one of the interest rate swaps in accordance with the collateral requirements for this derivative.
v3.22.2.2
Fair Value Measurements (Tables)
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Fair Value Disclosures [Abstract]    
Valuation Techniques
The measurement of fair value results in classification into a hierarchy by the inputs used to determine the fair value as follows:
Level 1—
 		Unadjusted quoted prices in active markets accessible by the reporting entity for identical assets or liabilities.  Active markets are those in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing.
Level 2
 		—
 		Pricing inputs other than quoted market prices included in Level 1 that are based on observable market data and that are directly or indirectly observable for substantially the full term of the asset or liability.  These include quoted market prices for similar assets or liabilities, quoted market prices for identical or similar assets in markets that are not active, adjusted quoted market prices, inputs from observable data such as interest rate and yield curves, volatilities and default rates observable at commonly quoted intervals, and inputs derived from observable market data by correlation or other means.
Level 3—
 
Pricing inputs that are unobservable, or less observable, from objective sources.  Unobservable inputs are only to be used to the extent observable inputs are not available.  These inputs maintain the concept of an exit price from the perspective of a market participant and should reflect assumptions of other market participants.  An entity should consider all market participant assumptions that are available without unreasonable cost and effort.  These are given the lowest priority and are generally used in internally developed methodologies to generate management's best estimate of the fair value when no observable market data is available.
  
Unrealized Investment Gains (Losses) TVA recorded unrealized gains and losses related to its equity and trading debt securities held during each period as follows:
Unrealized Investment Gains (Losses)
For the years ended September 30
(in millions)
FundFinancial Statement Presentation20222021
NDTRegulatory assets$(396)$279 
ARTRegulatory assets(190)145 
SERPOther income, net(19)7 
DCPOther income, net(5)1 
  
Fair Value Measurements  
Fair Value Measurements
At September 30, 2022
(in millions)
Quoted Prices in Active
 Markets for
Identical Assets
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Assets
Investments    
Equity securities$534 $— $— $534 
Government debt securities(1)
358 36 — 394 
Corporate debt securities(2)
— 283 — 283 
Mortgage and asset-backed securities— 52 — 52 
Institutional mutual funds242 — — 242 
Forward debt securities contracts— 4 — 4 
Private equity funds measured at net asset value(3)
— — — 487 
Private real asset funds measured at net asset value(3)
— — — 369 
Private credit measured at net asset value(3)
— — — 103 
Commingled funds measured at net asset value(3)
— — — 1,203 
Total investments1,134 375 — 3,671 
Commodity contract derivatives— 152 — 152 
Commodity derivatives under the FHP— 123 — 123 
Total$1,134 $650 $— $3,946 
Quoted Prices in Active Markets for Identical Liabilities
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Liabilities
Currency swaps(4)
$— $240 $— $240 
Interest rate swaps— 905 — 905 
Commodity contract derivatives— 7 — 7 
Commodity derivatives under the FHP— 8 — 8 
Total$— $1,160 $— $1,160 
Notes
(1) Includes government-sponsored entities, including $358 million of U.S. Treasury securities within Level 1 of the fair value hierarchy.
(2) Includes both U.S. and foreign debt.
(3) Certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been categorized in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented on the Consolidated Balance Sheets.
(4) TVA records currency swaps net of cash collateral received from or paid to the counterparty if applicable, to the extent such amount is not recorded in Accounts payable and accrued liabilities. See Note 15 — Risk Management Activities and Derivative Transactions — Offsetting of Derivative Assets and Liabilities.
Fair Value Measurements
At September 30, 2021
(in millions)
Quoted Prices in Active
 Markets for
Identical Assets
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Assets
Investments    
Equity securities$634 $— $— $634 
Government debt securities(1)
573 24 — 597 
Corporate debt securities(2)
— 411 — 411 
Mortgage and asset-backed securities— 63 — 63 
Institutional mutual funds225 — — 225 
Forward debt securities contracts— 2 — 2 
Private equity funds measured at net asset value(3)
— — — 357 
Private real asset funds measured at net asset value(3)
— — — 272 
    Private credit measured at net asset value(3)
— — — 71 
Commingled funds measured at net asset value(3)
— — — 1,421 
Total investments1,432 500 — 4,053 
Commodity contract derivatives— 250 — 250 
Total$1,432 $750 $— $4,303 
Quoted Prices in Active Markets for Identical Liabilities
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)		Total
Liabilities
Currency swaps(4)
$— $83 $— $83 
Interest rate swaps— 1,639 — 1,639 
Commodity contract derivatives— 3 — 3 
Total$— $1,725 $— $1,725 
Notes
(1) Includes government-sponsored entities, including $573 million of U.S. Treasury securities within Level 1 of the fair value hierarchy.
(2) Includes both U.S. and foreign debt.
(3) Certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been categorized in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented on the Consolidated Balance Sheets.
(4) TVA records currency swaps net of cash collateral received from or paid to the counterparty, to the extent such amount is not recorded in Accounts payable and accrued liabilities. See Note 15 — Risk Management Activities and Derivative Transactions — Offsetting of Derivative Assets and Liabilities.
Estimated Values of Financial Instruments Not Recorded at Fair Value The estimated values of TVA's financial instruments not recorded at fair value at September 30, 2022 and 2021, were as follows:
Estimated Values of Financial Instruments Not Recorded at Fair Value
(in millions)
 At September 30, 2022At September 30, 2021
 Valuation ClassificationCarrying
Amount		Fair
Value		Carrying
Amount		Fair
Value
EnergyRight® receivables, net (including current portion)
Level 2$62 $62 $72 $71 
Loans and other long-term receivables, net (including current portion)Level 2105 96 99 94 
EnergyRight® financing obligations (including current portion)
Level 272 81 82 92 
Unfunded loan commitmentsLevel 2— — — 3 
Membership interests of VIEs subject to mandatory redemption (including current portion)Level 220 22 23 30 
Long-term outstanding power bonds, net (including current maturities)Level 217,856 18,070 18,485 24,309 
Long-term debt of VIEs, net (including current maturities)Level 21,007 989 1,049 1,307 
  
v3.22.2.2
Other Income (Expense), Net Other Income (Expense), Net (Tables)
 12 Months Ended
Sep. 30, 2022
Other Income and Expenses [Abstract]  
Other Income (Expense), Net
Income and expenses not related to TVA's operating activities are summarized in the following table:
Other Income, Net
For the years ended September 30
(in millions)
 202220212020
Bellefonte$— $(28)$— 
Interest income15 12 18 
External services16 13 12 
Gains (losses) on investments(17)16 9 
Miscellaneous(7)— (3)
Total other income, net$7 $13 $36 
v3.22.2.2
Benefit Plans Benefit Plans (Tables)
 12 Months Ended
Sep. 30, 2022
Retirement Benefits [Abstract]  
Obligations and Funded Status
The changes in plan obligations, assets, and funded status for the years ended September 30, 2022 and 2021, were as follows:
Obligations and Funded Status
For the years ended September 30
(in millions)
809,400,000 Pension BenefitsOther Post-Retirement Benefits
 2022202120222021
Change in benefit obligation    
Benefit obligation at beginning of year$13,348 $13,675 $498 $544 
Service cost53 57 17 18 
Interest cost378 368 15 16 
Plan participants' contributions5 5 — — 
Collections(1)
— — 15 17 
Actuarial (gain) loss (2,509)(25)(114)(53)
Net transfers (to) from variable fund/401(k) plan11 2 — — 
Expenses paid(6)(6)— — 
Benefits paid(744)(728)(43)(44)
Benefit obligation at end of year10,536 13,348 388 498 
Change in plan assets    
Fair value of net plan assets at beginning of year9,110 7,959 — — 
Actual return on plan assets(590)1,572 — — 
Plan participants' contributions5 5 — — 
Collections(1)
— — 15 17 
Net transfers (to) from variable fund/401(k) plan11 2 — — 
Employer contributions308 306 28 27 
Expenses paid(6)(6)— — 
Benefits paid(744)(728)(43)(44)
Fair value of net plan assets at end of year8,094 9,110 — — 
Funded status$(2,442)$(4,238)$(388)$(498)
Note
(1) Collections include retiree contributions as well as provider discounts and rebates.
Amounts Recognized on TVA's Consolidated Balance Sheets
Amounts related to these benefit plans recognized on TVA's Consolidated Balance Sheets consist of regulatory assets and liabilities that have not been recognized as components of net periodic benefit cost at September 30, 2022 and 2021, and the funded status of TVA's benefit plans, which are included in Accounts payable and accrued liabilities and Post-retirement and post-employment benefit obligations:
Amounts Recognized on TVA's Consolidated Balance Sheets
At September 30
(in millions)
 Pension BenefitsOther Post-Retirement Benefits
 2022202120222021
Regulatory assets (liabilities)$1,839 $3,636 $(70)$32 
Accounts payable and accrued liabilities(6)(7)(22)(24)
Pension and post-retirement benefit obligations(1)
(2,436)(4,231)(366)(474)
Note
(1) The table above excludes $270 million and $340 million of post-employment benefit costs that are recorded in Post-retirement and post-employment benefit obligations on the Consolidated Balance Sheets at September 30, 2022 and 2021, respectively.
Post-Retirement Benefit Costs Deferred as Regulatory Assets
Unrecognized amounts included in regulatory assets or liabilities yet to be recognized as components of accrued benefit cost at September 30, 2022 and 2021, consisted of the following:
Post-Retirement Benefit Costs Deferred as Regulatory Assets (Liabilities)
At September 30
(in millions)
 Pension BenefitsOther Post-Retirement Benefits
 2022202120222021
Unrecognized prior service credit$(424)$(517)$(76)$(93)
Unrecognized net loss2,186 4,062 6 125 
Amount capitalized due to actions of regulator77 91 — — 
Total regulatory assets (liabilities)$1,839 $3,636 $(70)$32 
Projected Benefit Obligations and Accumulated Benefit Obligations in Excess of Plan Assets
Information for the pension projected benefit obligation ("PBO") in excess of plan assets and other post-retirement accumulated postretirement benefit obligation ("APBO") has been disclosed in the Obligations and Funded Status table above. The following table provides the pension plan accumulated benefit obligation ("ABO") in excess of plan assets. The other post-retirement plans are unfunded or have no plan assets.
Accumulated Benefit Obligations in Excess of Plan Assets
At September 30
(in millions)
 20222021
Accumulated benefit obligation$10,508 $13,299 
Fair value of net plan assets8,094 9,110 
Components of Net Periodic Benefit Cost
The components of net periodic benefit cost and other amounts recognized as changes in regulatory assets for the years ended September 30, 2022, 2021, and 2020 were as follows:
Components of Net Periodic Benefit Cost
For the years ended September 30
(in millions)
 Pension BenefitsOther Post-Retirement Benefits
 202220212020202220212020
Service cost$53 $57 $55 $17 $18 $16 
Interest cost378 368 415 15 16 16 
Expected return on plan assets(435)(493)(488)— — — 
Amortization of prior service credit(93)(97)(97)(17)(18)(24)
Recognized net actuarial loss392 452 436 5 11 10 
Total net periodic benefit cost as actuarially determined295 287 321 20 27 18 
Amount expensed (capitalized) due to actions of regulator13 19 (15)— — — 
Net periodic benefit cost$308 $306 $306 $20 $27 $18 
Sensitivity to Certain Changes in Pension Assumptions The following chart reflects the sensitivity of pension cost to changes in certain actuarial assumptions:
Sensitivity to Certain Changes in Pension Assumptions
 
 
Actuarial Assumption
Change in Assumption
Impact on 2022 Pension Cost
(in millions)
Impact on 2022 Projected Benefit Obligation
(in millions)
Discount rate(0.25)%$16 $257 
Rate of return on plan assets(0.25)%19 N/A
Cost of living adjustments0.25 %29 179 
Asset Holdings and Fair Value Measurements At September 30, 2022 and 2021, the asset holdings of TVARS included the following:
Asset Holdings of TVARS
  Plan Assets at September 30
Asset CategoryTarget Allocation20222021
Growth assets17 %20 %18 %
Defensive growth assets38 %34 %35 %
Defensive assets20 %18 %20 %
Inflation-sensitive assets25 %28 %27 %
Total100 %100 %100 %
Fair Value Measurements

    The following table provides the fair value measurement amounts for assets held by TVARS at September 30, 2022:
TVA Retirement System
At September 30, 2022
(in millions)
 
Total(1)(2)
Quoted Prices in Active Markets for Identical
Assets/Liabilities
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)
Assets    
Equity securities$709 $707 $— $2 
Preferred securities6 1 5 — 
Debt securities   
Corporate debt securities1,087 — 1,087 — 
Residential mortgage-backed securities293 — 289 4 
    Debt securities issued by U.S. Treasury616 616 — — 
Debt securities issued by foreign governments
130 — 130 — 
Asset-backed securities
176 — 136 40 
Debt securities issued by state/local governments
23 — 23 — 
Commercial mortgage-backed securities
161 — 145 16 
Commingled funds measured at net asset value(3)
Equity436 — — — 
Debt657 — — — 
Blended111 — — — 
Institutional mutual funds454 454 — — 
Cash equivalents and other short-term investments431 133 298 — 
Private credit measured at net asset value(3)
522 — — — 
Private equity measured at net asset value(3)
1,454 — — — 
Private real assets measured at net asset value(3)
1,080 — — — 
Securities lending collateral196 — 196 — 
Derivatives    
Futures
5 5 — — 
Swaps17 — 17 — 
Foreign currency forward receivable2 — 2 — 
Total assets$8,566 $1,916 $2,328 $62 
Liabilities    
Derivatives
Futures$10 $10 $— $— 
Foreign currency forward payable1 — 1 — 
Swaps54 — 54 — 
Securities sold under agreements to repurchase111 — 111 — 
Total liabilities$176 $10 $166 $— 
Notes
(1)  Excludes approximately $100 million in net payables associated with security purchases and sales and various other payables.
(2)  Excludes a $196 million payable for collateral on loaned securities in connection with TVARS's participation in securities lending programs.
(3) In accordance with Subtopic 820-10, certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy.
    The following table provides the fair value measurement amounts for assets held by TVARS at September 30, 2021:
TVA Retirement System
At September 30, 2021
(in millions)
 
Total(1)(2)
Quoted Prices in Active Markets for Identical
Assets/Liabilities
(Level 1)		Significant Other
Observable Inputs
(Level 2)		Significant
Unobservable
Inputs
(Level 3)
Assets    
Equity securities$992 $990 $— $2 
Preferred securities9 2 6 1 
Debt securities   
Corporate debt securities1,360 — 1,359 1 
Residential mortgage-backed securities275 — 267 8 
Debt securities issued by U.S. Treasury741 741 — — 
Debt securities issued by foreign governments204 — 200 4 
Asset-backed securities151 — 110 41 
Debt securities issued by state/local governments28 — 28 — 
Commercial mortgage-backed securities
168 — 151 17 
Commingled funds measured at net asset value(3)
Equity619 — — — 
Debt881 — — — 
Blended105 — — — 
Institutional mutual funds841 841 — — 
Cash equivalents and other short-term investments710 323 387 — 
Private credit measured at net asset value(3)
324 — — — 
Private equity measured at net asset value(3)
1,333 — — — 
Private real assets measured at net asset value(3)
760 — — — 
Securities lending collateral240 — 240 — 
Derivatives
Futures
1 1 — — 
Swaps
6 — 6 — 
Foreign currency forward receivable1 — 1 — 
Total assets$9,749 $2,898 $2,755 $74 
Liabilities    
Derivatives
Futures$4 $4 $— $— 
Foreign currency forward payable1 — 1 — 
Swaps23 — 23 — 
Securities sold under agreements to repurchase108 — 108 — 
Total liabilities$136 $4 $132 $— 
Notes
(1)  Excludes approximately $263 million in net payables associated with security purchases and sales and various other payables.
(2)  Excludes a $240 million payable for collateral on loaned securities in connection with TVARS's participation in securities lending programs.
(3) In accordance with Subtopic 820-10, certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy.
Fair Value Measurements Using Significant Unobservable Inputs
The following table provides a reconciliation of beginning and ending balances of pension plan assets measured at fair value on a recurring basis where the determination of fair value includes significant unobservable inputs (Level 3):
Fair Value Measurements Using Significant Unobservable Inputs
(in millions)
 Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Balance at September 30, 2020
$94 
Net realized/unrealized gains (losses)(48)
Purchases, sales, issuances, and settlements (net)32 
Transfers in and/or out of Level 3(4)
Balance at September 30, 2021
74 
Net realized/unrealized gains (losses)(4)
Purchases, sales, issuances, and settlements (net)2 
Transfers in and/or out of Level 3(10)
Balance at September 30, 2022
$62 
Estimated Future Benefit Payments
Cash Flows

Estimated Future Benefit Payments.  The following table sets forth the estimated future benefit payments under the benefit plans.
Estimated Future Benefits Payments
At September 30, 2022
(in millions)
 
Pension
Benefits(1)
Other Post-Retirement Benefits
2023$793 $22 
2024808 21 
2025813 21 
2026810 21 
2027807 22 
2028 - 20323,932 126 
Note
(1) Participants are assumed to receive the Fixed Fund in a lump sum in lieu of available annuity options allowed for certain grandfathered participants resulting in higher estimated pension benefits payments.
Amounts recognized on Consolidated Balance Sheets
Amounts Recognized on TVA's Consolidated Balance Sheets
At September 30
(in millions)
 20222021
Accounts payable and accrued liabilities(1)
$29 $— 
Post-retirement and post-employment benefit obligations270 340 
v3.22.2.2
Commitments and Contingencies (Tables)
 12 Months Ended
Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]  
Unfunded loan commitments At September 30, 2022, TVA had no commitments under unfunded loan commitments for 2023. TVA also has no commitments under unfunded loan commitments for 2024 through 2027.
v3.22.2.2
Related Parties Related Parties (Tables)
 12 Months Ended
Sep. 30, 2022
Related Party Transactions [Abstract]  
Related Party Transactions Transactions with agencies of the federal government were as follows:
Related Party Transactions
At or for the years ended September 30
(in millions)
 202220212020
Revenue from sales of electricity$134 $109 $105 
Other income296 280 260 
Expenditures
Operating expenses228 214 224 
Additions to property, plant, and equipment11 10 9 
Cash and cash equivalents30 30 31 
Accounts receivable, net78 65 94 
Investment funds358 573 485 
Long-term accounts receivable43 31 27 
Accounts payable and accrued liabilities42 15 39 
Long-term power bonds, net1 1 1 
Return on power program appropriation investment4 4 6 
v3.22.2.2
Revenue (Tables)
 12 Months Ended
Sep. 30, 2022
Revenue from Contract with Customer [Abstract]  
Revenues
Revenues

TVA recognizes revenue from contracts with customers to depict the transfer of goods or services to customers in an amount to which the entity expects to be entitled in exchange for those goods or services. For the generation and transmission of electricity, this is generally at the time the power is delivered to a metered customer delivery point for the customer's consumption or distribution. As a result, revenues from power sales are recorded as electricity is delivered to customers. In addition to power sales invoiced and recorded during the month, TVA accrues estimated unbilled revenues for power sales provided to five customers whose billing date occurs prior to the end of the month.  Exchange power sales are presented in the accompanying Consolidated Statements of Operations as a component of sales of electricity. Exchange power sales are sales of excess power after meeting TVA native load and directly served requirements.  Native load refers to the customers on whose behalf a company, by statute, franchise, regulatory requirement, or contract, has undertaken an obligation to serve. TVA engages in other arrangements in addition to power sales. Certain other revenue from activities related to TVA's overall mission is recorded in Other revenue. Revenues that are not related to the overall mission are recorded in Other income, net.
Contract with Customer, Asset and Liability [Table Text Block]
Contract Balances

    Contract assets represent an entity's right to consideration in exchange for goods and services that the entity has transferred to customers. TVA did not have any material contract assets at September 30, 2022.

    Contract liabilities represent an entity's obligations to transfer goods or services to customers for which the entity has received consideration (or an amount of consideration is due) from the customers. These contract liabilities are primarily related to upfront consideration received prior to the satisfaction of the performance obligation. See Economic Development Incentives below and Note 12 — Other Long-Term Liabilities — Long-Term Deferred Revenue.
v3.22.2.2
Leases (Table Text Block)
 12 Months Ended
Sep. 30, 2022
Leases [Abstract]  
Amounts Recognized on Balance Sheets The following table provides information regarding the presentation of leases on the Consolidated Balance Sheets:
Amounts Recognized on TVA's Consolidated Balance Sheets
At September 30
(in millions)
20222021
Assets
  OperatingOperating lease assets, net of amortization$155 $165 
  FinanceFinance leases630 692 
Total lease assets$785 $857 
Liabilities
Current
  OperatingAccounts payable and accrued liabilities$59 $40 
  FinanceAccounts payable and accrued liabilities59 60 
Non-current
  OperatingOther long-term liabilities93 122 
  FinanceFinance lease liabilities628 687 
Total lease liabilities$839 $909 
Lease Costs TVA's leases consist primarily of railcars, equipment, real estate/land, power generating facilities, and gas pipelines. TVA's leases have various terms and expiration dates remaining from less than one year to approximately 24 years. The components of lease costs were as follows:
Lease Costs
For the years ended September 30
(in millions)
202220212020
Operating lease costs(1)
$56 $52 $84 
Variable lease costs(1)
78 75 75 
Short-term lease costs(1)
26 12 7 
Finance lease costs
Amortization of lease assets(2)
58 51 15 
Interest on lease liabilities(3)(4)
42 39 33 
Total finance lease costs100 90 48 
     Total lease costs$260 $229 $214 
Notes
(1) Costs are included in Operating and maintenance expense, Fuel expense, Purchased power expense, and Tax equivalents expense on the Consolidated Statements of Operations.
(2) Expense is included in Depreciation and amortization expense on the Consolidated Statements of Operations.
(3) Expense is included in Interest expense on the Consolidated Statements of Operations.
(4) Certain finance leases receive regulatory accounting treatment and are reclassified to Fuel expense and Purchased power expense.
Amounts Recognized on Statements of Cash Flows
The following table contains additional information with respect to cash and non-cash activities related to leases:
Amounts Recognized on TVA's Consolidated Statements of Cash Flows
For the years ended September 30
(in millions)
202220212020
Operating cash flows for operating leases$57 $53 $85 
Operating cash flows for finance leases42 39 33 
Financing cash flows for finance leases60 52 15 
Lease assets obtained in exchange for lease obligations (non-cash)
Operating leases(1)
$43 $(22)$110 
Finance leases— 233 394 
Note
(1) Amount for 2021 represents a non-cash reduction due to a lease that was amended during the fiscal year resulting in derecognition of the operating lease asset and obligation upon remeasurement.
Weighted Averages
TVA has certain finance leases under PPAs under which the present value of the minimum lease payments exceeds the fair value of the related lease asset at the date of measurement.  This resulted in an interest rate that was higher than TVA's incremental borrowing rate. The weighted average remaining lease term in years and the weighted average discount rate for TVA's operating and financing leases were as follows:
Weighted Averages
At September 30
20222021
Weighted average remaining lease terms
Operating leases3 years5 years
Finance leases11 years12 years
Weighted average discount rate(1)
Operating leases1.5%1.5%
Finance leases17.8%17.7%
Note
(1) The discount rate is calculated using the rate implicit in a lease if it is readily determinable. If the rate used by the lessor is not readily determinable, TVA uses its incremental borrowing rate as permitted by accounting guidance. The incremental borrowing rate is influenced by TVA's credit rating and lease term and as such may differ for individual leases, embedded leases, or portfolios of leased assets.
Future Minimum Lease Payments The following table presents maturities of lease liabilities and a reconciliation of the undiscounted cash flows to lease liabilities at September 30, 2022:
Future Minimum Lease Payments
Minimum payments due at September 30, 2022
(in millions)
Operating leases
2023$61 
202443 
202535 
202610 
20272 
Thereafter5 
Minimum annual payments156 
Less: present value discount(4)
Operating present value of net minimum lease payments$152 
Finance leases
2023$112 
2024107 
2025106 
2026105 
2027104 
   Thereafter552 
Minimum annual payments1,086 
Less: amount representing interest(399)
Finance present value of net minimum lease payments$687 
v3.22.2.2
Deferred Costs, Capitalized, Prepaid, and Other Assets (Tables)
 12 Months Ended
Sep. 30, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]  
Schedule of Other Current Assets
Other Current Assets 
At September 30
(in millions)
 20222021
Commodity contract derivative assets$172 $210 
Other85 77 
Other current assets$257 $287 
v3.22.2.2
Summary of Significant Accounting Policies - General (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
People
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2015
USD ($)
Accounting Policies [Abstract]          
Cash and Cash Equivalents, at Carrying Value $ 500 $ 499      
Allowance for uncollectible accounts - loans 3 4      
Reimbursements from DOE 188        
Restricted Cash and Investments, Noncurrent 20 19      
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents 520 518 $ 521 $ 322  
Accounts receivable from DOE 9        
Appropriation-investment power program $ 258 258     $ 1,000
Population of Service Area [Line Items]          
Population of service area | People 10,000,000        
Cash and Cash Equivalents, at Carrying Value $ 500 499      
Restricted Cash and Investments, Noncurrent $ 20 $ 19      
v3.22.2.2
Summary of Significant Accounting Policies - Reclassificatons (Details)
$ in Millions
Sep. 30, 2022
USD ($)
Reclassifications  
Finance Lease, Liability $ 687
v3.22.2.2
Summary of Significant Accounting Policies - Allowance for Uncollectible Accounts (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Portion at Other than Fair Value Measurement [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Financing Receivable, after Allowance for Credit Loss $ 105 $ 99
Financing Receivable, after Allowance for Credit Loss 96 94
Allowance for uncollectible accounts - receivables 1 1
Allowance for uncollectible accounts - loans $ 3 $ 4
v3.22.2.2
Summary of Significant Accounting Policies - Property, Plant, and Equipment, and Depreciation (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Property, Plant, and Equipment, and Depreciation      
Depreciation $ 1,800 $ 1,400 $ 1,600
Composite depreciation rate for completed plant 2.98% 2.28% 2.74%
Reacquired Rights $ 178 $ 184  
Amortization of Reacquired Rights $ 6 8 $ 8
Capitalized software amortization period 7 years    
Accelerated depreciation $ 140 136 $ 125
Increase (decrease) in Year 1 due to new depreciation study 345    
Accumulated Amortization of Reacquired Rights 42 $ 36  
Amortization Reacquired Rights, Year 1 6    
Amortization Reacquired Rights, Year 2 6    
Amortization Reacquired Rights, Year 3 6    
Amortization Reacquired Rights, Year 4 6    
Amortization Reacquired Rights, Year 5 6    
Amortization Reacquired Rights, Year Thereafter $ 148    
Nuclear      
Property, Plant, and Equipment, and Depreciation      
Composite depreciation rate for completed plant 2.72% 2.38% 2.38%
Coal-fired      
Property, Plant, and Equipment, and Depreciation      
Composite depreciation rate for completed plant 4.27% 1.95% 3.62%
Hydroelectric      
Property, Plant, and Equipment, and Depreciation      
Composite depreciation rate for completed plant 1.85% 1.60% 1.60%
Gas and oil-fired      
Property, Plant, and Equipment, and Depreciation      
Composite depreciation rate for completed plant 3.38% 2.98% 3.04%
Transmission      
Property, Plant, and Equipment, and Depreciation      
Composite depreciation rate for completed plant 1.51% 1.34% 1.34%
Other      
Property, Plant, and Equipment, and Depreciation      
Composite depreciation rate for completed plant 3.64% 7.12% 7.26%
v3.22.2.2
Summary of Significant Accounting Policies - Energy Prepayment Obligations and Discounts on Sales (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Energy Prepayment Obligations and Discounts on Sales    
Accounts Receivable, Allowance for Credit Loss, Current $ 1 $ 1
v3.22.2.2
Summary of Significant Accounting Policies - Leases (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Leases      
Finance lease under PPA $ 425 $ 464  
Operating lease under PPA 133 143  
Operating cash flows for operating leases $ 57 $ 53 $ 85
v3.22.2.2
Impact of New Accounting Standards and Interpretations (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Lessee, Lease, Description [Line Items]    
Operating Lease, Right-of-Use Asset $ 155 $ 165
v3.22.2.2
Accounts Receivable, Net Accounts Receivable, Net (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Power receivables $ 1,899 $ 1,480
Other receivables 108 86
Allowance for uncollectible accounts (1) [1] (1)
Accounts receivable, net $ 2,007 $ 1,566
[1] Allowance for uncollectible accounts was less than $1 million at both September 30, 2022 and 2021, and therefore is not represented in the table above.
v3.22.2.2
Inventories, Net Inventories, Net (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Inventories, Net    
Materials and supplies inventory $ 808 $ 775
Fuel inventory 303 198
Renewable energy certificates/emissions allowance inventory, net 18 12
Allowance for inventory obsolescence (57) (35)
Inventories, net 1,072 $ 950
Increase (Decrease) in Coal Inventories 58  
Increase (Decrease) in Fuel Inventories 105  
Increase (Decrease) in Other Fossil Fuel Inventories $ 32  
v3.22.2.2
Net Completed Plant Net Completed Plant (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Completed Plant    
Completed plant cost $ 66,442 $ 66,411
Accumulated depreciation 34,239 34,663
Net completed plant 32,203 31,748
Coal-fired    
Completed Plant    
Completed plant cost 18,145 19,319
Accumulated depreciation 13,649 14,357
Net completed plant 4,496 4,962
Gas and oil-fired    
Completed Plant    
Completed plant cost 6,112 6,076
Accumulated depreciation 1,957 1,824
Net completed plant 4,155 4,252
Nuclear    
Completed Plant    
Completed plant cost 26,629 26,024
Accumulated depreciation 12,928 12,632
Net completed plant 13,701 13,392
Transmission    
Completed Plant    
Completed plant cost 8,919 8,597
Accumulated depreciation 3,301 3,215
Net completed plant 5,618 5,382
Hydroelectric    
Completed Plant    
Completed plant cost 3,987 3,525
Accumulated depreciation 1,192 1,135
Net completed plant 2,795 2,390
Other electrical plant    
Completed Plant    
Completed plant cost 1,724 1,943
Accumulated depreciation 807 1,103
Net completed plant 917 840
Multipurpose dams    
Completed Plant    
Completed plant cost 900 900
Accumulated depreciation 396 388
Net completed plant 504 512
Other stewardship    
Completed Plant    
Completed plant cost 26 27
Accumulated depreciation 9 9
Net completed plant $ 17 $ 18
v3.22.2.2
Other Long-Term Assets (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Other Long-Term Assets    
EnergyRight receivables $ 62 $ 71
Prepaid Expense, Noncurrent 74 44
Restricted Cash and Investments, Noncurrent 20 19
Total other long-term assets 394 320
Prepaid Expense, Current 12  
Loans and Leases Receivable, Allowance 3 4
Financing Receivable, after Allowance for Credit Loss, Current 6 3
Other Assets, Miscellaneous, Current 85 77
EnergyRight loan reserve    
Other Long-Term Assets    
Loans and Leases Receivable, Allowance 1 1
Economic development loan collective reserve    
Other Long-Term Assets    
Loans and Leases Receivable, Allowance 1 1
Economic development loan specific loan reserve    
Other Long-Term Assets    
Loans and Leases Receivable, Allowance 1 2
Accounts Receivable [Member]    
Other Long-Term Assets    
EnergyRight receivables 13 15
Other long-term assets    
Other Long-Term Assets    
EnergyRight receivables 49 57
Loans and other long-term receivables, net 99 96
Commodity contract derivative assets 102 40
Other $ 70 $ 83
Energy Right    
Other Long-Term Assets    
Number of days in default 180 days  
Minimum | Energy Right    
Other Long-Term Assets    
EnergyRight loan terms 5 years  
Maximum | Energy Right    
Other Long-Term Assets    
EnergyRight loan terms 10 years  
v3.22.2.2
Regulatory Assets and Liabilities Regulatory Assets and Liabilities (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Regulatory Assets and Liabilities      
Non-current regulatory liabilities $ 172 $ 40  
Current regulatory assets 138 196  
Regulatory assets 6,134 7,956  
Regulatory Assets 6,272 8,152  
Current regulatory liabilities 391 340  
Regulatory asset amount expensed 70 72 $ 21
Regulatory Liabilities 563 380  
Change in nuclear decommissioning costs 458    
Deferred Project Costs [Member]      
Regulatory Assets and Liabilities      
Gallatin coal combustion residual facilities estimated cost to cap and close 47 114  
Regulatory Asset      
Regulatory Assets and Liabilities      
Regulatory assets 138 150  
Removal Costs [Member]      
Regulatory Assets and Liabilities      
Regulatory assets 479 1,122  
Unrealized losses on interest rate derivatives      
Regulatory Assets and Liabilities      
Current regulatory assets 14 3  
Regulatory assets 1 0  
Non-nuclear decommissioning costs      
Regulatory Assets and Liabilities      
Regulatory assets 2,856 2,653  
Pension Costs [Member]      
Regulatory Assets and Liabilities      
Regulatory assets 1,839 3,668  
Deferred Fuel Costs [Member]      
Regulatory Assets and Liabilities      
Current regulatory assets 77 79  
Nuclear decommissioning costs      
Regulatory Assets and Liabilities      
Regulatory assets 821 363  
Unrealized gains/losses on commodity derivatives      
Regulatory Assets and Liabilities      
Non-current regulatory liabilities 102 40  
Current regulatory liabilities 173 210  
Deferred other post-retirement benefits cost      
Regulatory Assets and Liabilities      
Non-current regulatory liabilities 70 0  
Fuel cost adjustment tax equivalents      
Regulatory Assets and Liabilities      
Current regulatory liabilities $ 218 $ 130  
v3.22.2.2
Variable Interest Entities (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2013
Sep. 30, 2012
Liabilities          
Current maturities of long-term debt of variable interest entities issued at par $ 39 $ 43      
Liabilities, Current 4,645 4,979      
Other long-term liabilities 1,485 2,041      
Long-term debt of variable interest entities, net 968 1,006      
VIE Financing          
Face Amount $ 40     $ 360  
Rate of Return SHLLC 7.00%        
Accrued interest $ 10 10      
Minimum payments on membership interests subject to mandatory redemption, due in next twelve months 2        
Minimum payments on membership interests subject to mandatory redemption, due in year two 1        
Minimum payments on membership interests subject to mandatory redemption, due in year three 1        
Minimum payments on membership interests subject to mandatory redemption, due in year four 1        
Minimum payments on membership interests subject to mandatory redemption, due in year five 1        
Minimum payments on membership interests subject to mandatory redemption, due thereafter 14        
Other Long-term Debt, Maturity, Year One 39        
Other Long-term Debt, Maturity, Year Two 36        
Other Long-term Debt, Maturity, Year Three 37        
Other Long-term Debt, Maturity, Year Four 39        
Other Long-term Debt, Maturity, Year Five 40        
Other Long-term Debt, Maturity, Year Six 822        
SCCG          
VIE Financing          
Debt and Lease Obligation       $ 400  
Holdco          
VIE Financing          
Face Amount         $ 100
JSCCG          
VIE Financing          
Face Amount         900
Variable Interest Entity, Primary Beneficiary [Member]          
Liabilities          
Liabilities, Current 51 56      
Other long-term liabilities 18 20      
VIE Financing          
Accounts Payable and Accrued Liabilities 2 3      
Liabilities 1,037 1,082     $ 1,000
Interest Expense $ 50 $ 52 $ 54    
v3.22.2.2
Asset Retirement Obligations Asset Retirement Obligations (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Liabilities Settled [Line Items]      
Increase in ARO liability $ 160    
Change in estimate [1] 247 $ 203  
Additional obligations [1]   43  
Balance [1] 7,162 7,002 $ 6,785
Asset Retirement Obligation, Liabilities Settled [1] 311 242  
Accretion (recorded as regulatory asset) [1] 224 213  
Asset Retirement Obligation, Current 275 266  
Amortization and Depreciation of Decontaminating and Decommissioning Assets 137 72 169
Total ARO change due to CCR 82 122  
Change in ARO from operating CCR facilities   30  
Change in ARO from inactive CCR facilities   13  
ARO change due to groundwater monitoring   69  
Accounts payable and accrued liabilities      
Liabilities Settled [Line Items]      
Asset Retirement Obligation, Liabilities Settled 20    
Nuclear      
Liabilities Settled [Line Items]      
Change in estimate 61 12  
Additional obligations   0  
Balance 3,643 3,428 3,278
Asset Retirement Obligation, Liabilities Settled 2 11  
Accretion (recorded as regulatory asset) 156 149  
Change due to cost study 58    
Non-nuclear      
Liabilities Settled [Line Items]      
Change in estimate 186 191  
Additional obligations   43  
Balance 3,519 3,574 $ 3,507
Asset Retirement Obligation, Liabilities Settled 309 231  
Accretion (recorded as regulatory asset) 68 $ 64  
Change in estimate due to coal fines 119    
Change in estimate due to closure of coal yards 57    
Change in estimate due to timing of maintenance 53    
Change in estimate due to timing of asset retirement activities 47    
Change in estimate due to Gallatin CCR closure 30    
Change in cost estimates at Allen $ 15    
[1]
(1) Includes $275 million and $266 million at September 30, 2022 and 2021, respectively, in Current liabilities.
(2) Settlements include the change in asset retirement obligation project accruals included in Accounts payable and accrued liabilities of $20 million.
v3.22.2.2
Other Long-Term Liabilities Other Long-Term Liabilities (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Other Long-Term Liabilities    
Interest rate swaps $ 905 $ 1,639
Derivative Liability (734)  
Currency swap liabilities 240 83 [1]
EnergyRight financing obligation (81) (92)
Deferred Revenue, Noncurrent 39 37
Non-current regulatory liabilities 172 40
Total other long-term liabilities 1,485 $ 2,041
Finance Lease, Liability $ 687  
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] Other Liabilities Other Liabilities
Deferred Compensation Liability, Current $ (53) $ (51)
Current portion of energy prepayment obligations 16 17
Change in currency swap liabilities 157  
Other long-term liabilities    
Other Long-Term Liabilities    
Interest rate swaps 851 1,524
Currency swap liabilities 228 76
EnergyRight financing obligation (58) (66)
Environmental agreements liability 39 42
Customer Advances for Construction 53 24
Membership interests of VIE subject to mandatory redemption 0 29
Other 124 121
Accounts payable and accrued liabilities    
Other Long-Term Liabilities    
Interest rate swaps 54 115
Service agreements (32) (28)
EnergyRight financing obligation (14) (16)
Customer Advances for Construction $ 33 $ 38
[1] See Note 15 — Risk Management Activities and Derivative Transactions — Offsetting of Derivative Assets and Liabilities.
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - General (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2013
Jan. 17, 2012
Debt Instrument      
Interest rate     7.10%
Debt ceiling $ 30,000    
Face Amount $ 40 $ 360  
PARRS 1998 Series D Bond      
Debt Instrument      
PARRS interest rate after rate reset 2.134%    
Amount of bonds redeemed $ 318    
Amount of redeemable bond issues outstanding $ 256    
PARRS interest rate after rate reset 2.134%    
PARRS 1999 Series A Bond      
Debt Instrument      
PARRS interest rate after rate reset 2.216%    
Amount of bonds redeemed $ 316    
Amount of redeemable bond issues outstanding $ 208    
PARRS interest rate after rate reset 2.216%    
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Secured Debt of VIEs (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2013
Aug. 09, 2013
Sep. 30, 2012
Jan. 17, 2012
Variable Interest Entities            
Face Amount $ 40   $ 360      
Interest rate           7.10%
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount 22 $ 30        
Long-term debt of variable interest entities (including current maturities) 989 $ 1,307        
SCCG            
Variable Interest Entities            
Interest rate       3.846%    
JSCCG            
Variable Interest Entities            
Face Amount         $ 900  
Debt Instrument, Interest Rate           4.626%
Holdco            
Variable Interest Entities            
Face Amount         $ 100  
Holdco balloon payment upon maturity $ 10          
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Secured Notes of SPEs (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2013
Jan. 17, 2012
Secured notes      
Secured notes $ 40 $ 360  
Interest rate     7.10%
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Short-Term Debt (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Short-Term Debt, Gross [Line Items]    
Short-Term Debt $ 1,172 $ 780
Short-term Borrowings Gross $ 1,173 $ 780
Weighted average interest rate - discount notes 2.93% 0.03%
Foreign Currency Transaction Gain (Loss), Unrealized $ 150  
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Put and Call Options (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
PARRS 1998 Series D Bond  
Debt Instrument  
Amount of redeemable bond issues outstanding $ 256
PARRS interest rate prior to rate reset 6.75%
PARRS interest rate after rate reset 2.134%
Amount of bonds redeemed $ 318
PARRS 1999 Series A Bond  
Debt Instrument  
Amount of redeemable bond issues outstanding $ 208
PARRS interest rate prior to rate reset 6.50%
PARRS interest rate after rate reset 2.216%
Amount of bonds redeemed $ 316
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Debt Securities Activity (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2013
Jan. 17, 2012
Debt Instrument          
Issues of power bonds $ 484 $ 500 $ 997    
Face Amount 40     $ 360  
Discount on debt issues (16) 0      
Redemptions/Maturities of variable interest entities 43 41 39    
Redemptions/Maturities of power bonds $ 1,028 $ 1,860 $ 1,427    
Percent of par value 96.786% 99.982%      
Total Current maturities of power bonds issued at par $ 29 $ 1,028      
Interest rate         7.10%
Short-term debt, net of discounts 1,172 780      
Current maturities of long-term debt of variable interest entities issued at par 39 43      
Long-term power bonds, net 17,826 17,457      
880591EF5 (12.15.20)          
Debt Instrument          
Total Current maturities of power bonds issued at par $ 1 1      
Interest rate 3.77%        
Debt Instrument, Maturity Date Dec. 15, 2022        
880591EF5 (6.15.21)          
Debt Instrument          
Total Current maturities of power bonds issued at par $ 28 27      
Interest rate 3.77%        
Debt Instrument, Maturity Date Jun. 15, 2023        
880591EN8          
Debt Instrument          
Total Current maturities of power bonds issued at par $ 0 $ 1,000      
Interest rate 1.875%        
Debt Instrument, Maturity Date Aug. 15, 2022        
Total          
Debt Instrument          
Debt Instrument, Redemption Period, End Date 1,071 1,901      
Percent of par value 100.00%        
Debt of variable interest entities          
Debt Instrument          
Redemptions/Maturities of variable interest entities $ 43 $ 41      
2009 Series B          
Debt Instrument          
Redemptions/Maturities of power bonds 28 29      
2011 Series A          
Debt Instrument          
Redemptions/Maturities of power bonds 0 1,500      
1998 Series H          
Debt Instrument          
Redemptions/Maturities of power bonds 0 331      
2012 Series A          
Debt Instrument          
Redemptions/Maturities of power bonds 1,000 0      
Total          
Debt Instrument          
Debt Securities Issues 484 500      
2021 Series A          
Debt Instrument          
Debt Securities Issues $ 0        
880591EY4          
Debt Instrument          
Interest rate 4.25%        
Debt Instrument, Maturity Date Sep. 15, 2052        
Long-term power bonds, net $ 500 0      
880591EX6          
Debt Instrument          
Interest rate 1.50%        
Debt Instrument, Maturity Date Sep. 15, 2031        
Long-term power bonds, net $ 500 $ 500      
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Debt Outstanding (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Jan. 17, 2012
Short-term debt      
Coupon rate     7.10%
Short-term debt, net of discounts $ 1,172 $ 780  
Current maturities of long-term debt of variable interest entities issued at par 39 43  
Total Current maturities of power bonds issued at par 29 1,028  
Current maturities of power bonds 29 1,028  
Total current debt outstanding, net 1,240 1,851  
Long-term debt      
Long-term power bonds, net 17,826 17,457  
Long-term power bonds [1] 17,950 17,572  
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net (124) (115)  
Long-term debt of variable interest entities, net 968 1,006  
Total long-term debt, net 18,794 18,463  
Foreign Currency Transaction Gain (Loss), before Tax $ 150 58  
880591DX7      
Short-term debt      
Coupon rate 4.65%    
Debt Instrument, Maturity Date Jun. 15, 2035    
Long-term debt      
Long-term power bonds, net $ 436 436  
880591EF5      
Short-term debt      
Coupon rate 3.77%    
Debt Instrument, Maturity Date Jun. 15, 2034    
Long-term debt      
Long-term power bonds, net $ 160 190  
880591ER9      
Short-term debt      
Coupon rate 2.875%    
Debt Instrument, Maturity Date Sep. 15, 2024    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591CJ9      
Short-term debt      
Coupon rate 6.75%    
Debt Instrument, Maturity Date Nov. 01, 2025    
Long-term debt      
Long-term power bonds, net $ 1,350 1,350  
880591EU2 [Member]      
Short-term debt      
Coupon rate 2.875%    
Debt Instrument, Maturity Date Feb. 01, 2027    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591300      
Short-term debt      
Coupon rate 2.134%    
Debt Instrument, Maturity Date Jun. 01, 2028    
Long-term debt      
Long-term power bonds, net $ 256 256  
880591409      
Short-term debt      
Coupon rate 2.216%    
Debt Instrument, Maturity Date May 01, 2029    
Long-term debt      
Long-term power bonds, net $ 208 208  
880591DM1      
Short-term debt      
Coupon rate 7.125%    
Debt Instrument, Maturity Date May 01, 2030    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591DV1      
Short-term debt      
Coupon rate 4.70%    
Debt Instrument, Maturity Date Jul. 15, 2033    
Long-term debt      
Long-term power bonds, net $ 472 472  
880591DP4      
Short-term debt      
Coupon rate 6.587%    
Debt Instrument, Maturity Date Jun. 07, 2032    
Long-term debt      
Long-term power bonds, net $ 279 337  
880591CK6      
Short-term debt      
Coupon rate 5.98%    
Debt Instrument, Maturity Date Apr. 01, 2036    
Long-term debt      
Long-term power bonds, net $ 121 121  
880591CS9      
Short-term debt      
Coupon rate 5.88%    
Debt Instrument, Maturity Date Apr. 01, 2036    
Long-term debt      
Long-term power bonds, net $ 1,500 1,500  
880591CP5      
Short-term debt      
Coupon rate 6.15%    
Debt Instrument, Maturity Date Jan. 15, 2038    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591ED0      
Short-term debt      
Coupon rate 5.50%    
Debt Instrument, Maturity Date Jun. 15, 2038    
Long-term debt      
Long-term power bonds, net $ 500 500  
880591EH1      
Short-term debt      
Coupon rate 5.25%    
Debt Instrument, Maturity Date Sep. 15, 2039    
Long-term debt      
Long-term power bonds, net $ 2,000 2,000  
880591EP3      
Short-term debt      
Coupon rate 3.50%    
Debt Instrument, Maturity Date Dec. 15, 2042    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591DU3      
Short-term debt      
Coupon rate 4.962%    
Debt Instrument, Maturity Date Jun. 07, 2043    
Long-term debt      
Long-term power bonds, net $ 168 202  
880591EB4      
Short-term debt      
Coupon rate 4.875%    
Debt Instrument, Maturity Date Jan. 15, 2048    
Long-term debt      
Long-term power bonds, net $ 500 500  
880591DZ2      
Short-term debt      
Coupon rate 5.375%    
Debt Instrument, Maturity Date Apr. 01, 2056    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591EJ7      
Short-term debt      
Coupon rate 4.625%    
Debt Instrument, Maturity Date Sep. 15, 2060    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591ES7      
Short-term debt      
Coupon rate 4.25%    
Debt Instrument, Maturity Date Sep. 15, 2065    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591EW8 [Member]      
Short-term debt      
Coupon rate 0.75%    
Debt Instrument, Maturity Date May 15, 2025    
Long-term debt      
Long-term power bonds, net $ 1,000 1,000  
880591EX6      
Short-term debt      
Coupon rate 1.50%    
Debt Instrument, Maturity Date Sep. 15, 2031    
Long-term debt      
Long-term power bonds, net $ 500 500  
880591EY4      
Short-term debt      
Coupon rate 4.25%    
Debt Instrument, Maturity Date Sep. 15, 2052    
Long-term debt      
Long-term power bonds, net $ 500 $ 0  
[1] Includes net exchange gain from currency transactions of $150 million and $58 million at September 30, 2022 and 2021
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Maturities Due (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2028
Sep. 30, 2027
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2024
Debt Instrument              
2018 $ 29            
2019 1,022            
2020 1,022            
2021 1,370            
2022 1,020            
Thereafter 13,666            
Total 18,129            
Short-Term Debt 1,172 $ 780          
Foreign Currency Transaction Gain (Loss), before Tax 150 58          
Net discount on sale of Bonds 82            
Foreign Currency Transaction Gain (Loss), Unrealized 150            
Short-term Borrowings Gross 1,173 $ 780          
Short-Term Debt              
Debt Instrument              
Debt issuance costs 1            
Scenario, Forecast              
Debt Instrument              
Short-Term Debt     $ 0 $ 0 $ 0 $ 0 $ 0
Power bonds              
Debt Instrument              
Debt issuance costs 42            
Other long-term debt              
Debt Instrument              
Debt issuance costs $ 6            
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Credit Facility Agreements (Details)
Sep. 30, 2022
USD ($)
Credit_facilities
Sep. 30, 2021
USD ($)
Credit Facility Agreements    
Letters of Credit Outstanding, Amount 3 $ 99,000,000  
Letter of Credit Outstanding, Amount 2 67,000,000  
Long-term Line of Credit, Borrowings 3 0  
Long-term Line of Credit, Borrowings 2 0  
Borrowings under U.S. Treasury credit facility 0  
Revolving Credit Facilities    
Credit Facility Agreements    
Current borrowing capacity 2,650,000,000  
Credit facility agreements borrowings outstanding $ 0  
Number of revolving credit facilities | Credit_facilities 4  
Revolving Credit Facility 4 $ 150,000,000  
Revolving credit facility 3 1,000,000,000  
Revolving credit facility 1 500,000,000  
Revolving Credit Facility 2 1,000,000,000  
Long-term Line of Credit, Borrowings 4 0  
Long-term Line of Credit, Borrowings 1 0  
Line of Credit Facility, Remaining Borrowing Capacity 4 933,000,000  
Line of Credit Facility, Remaining Borrowing Capacity 2 112,000,000  
Line of Credit Facility, Remaining Borrowing Capacity 3 0  
Line of Credit Facility, Remaining Borrowing Capacity 1 901,000,000  
Line of Credit Facility, Remaining Borrowing Capacity 1,946,000,000  
Letter of Credit    
Credit Facility Agreements    
Amount of letters of credit outstanding 704,000,000 $ 1,200,000,000
Letters of Credit Outstanding, Amount 4 38,000,000  
Letters of Credit Outstanding, Amount 1 $ 500,000,000  
v3.22.2.2
Debt and Other Obligations Debt and Other Obligations - Lease/Leasebacks (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Lease/Leasebacks [Abstract]    
CT and QTE outstanding leaseback obligation   $ 25
Kemper/Lagoon Creek Leasehold Interests    
Variable Interest Entities    
Leasehold Interests $ 155  
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Derivative Instruments That Receive Hedge Accounting Treatment (Details) - USD ($)
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Summary of Derivative Instruments That Receive Hedge Accounting Treatment      
Interest rate swaps $ 905,000,000 $ 1,639,000,000  
Ineffective portion excluded from testing 0    
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred 29,000,000    
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax (93,000,000) 97,000,000 $ 38,000,000
Accounts payable and accrued liabilities      
Summary of Derivative Instruments That Receive Hedge Accounting Treatment      
Interest rate swaps $ 54,000,000 $ 115,000,000  
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Derivative Instruments That Do Not Receive Hedge Accounting Treatment (Details)
 12 Months Ended
Sep. 30, 2022
USD ($)
Sep. 30, 2021
USD ($)
Derivative    
Change in Unrealized gains (losses) on Interest Rate Derivatives $ (728,000,000) $ (402,000,000)
Interest rate swaps 905,000,000 1,639,000,000
Unrealized gains/losses on derivatives 0  
Interest Rate Swap    
Derivative    
Fair value (233,000,000) (455,000,000)
Commodity Contract Derivatives    
Derivative    
Fair value $ 145,000,000 $ 247,000,000
Natural Gas Contract Derivatives    
Derivative    
Number of contracts 44 40
Notional amount 296,000,000 263,000,000
Fair value $ 145,000,000 $ 247,000,000
Commodity Contract under FHP    
Derivative    
Number of contracts 225 0
Notional amount 256  
Fair value $ 115,000,000 $ 0
Accounts payable and accrued liabilities    
Derivative    
Fair value 12,000,000 7,000,000
Interest rate swaps 54,000,000 115,000,000
Accounts payable and accrued liabilities | Interest Rate Swap    
Derivative    
Fair value (3,000,000) (22,000,000)
Accounts payable and accrued liabilities | Commodity Contract Derivatives    
Derivative    
Fair value   (3,000,000)
Accounts payable and accrued liabilities | Commodity Contract under FHP    
Derivative    
Fair value (8,000,000)  
Other Regulatory Assets (Liabilities) | Interest Rate Swap    
Derivative    
Unrealized gains/losses on derivatives (103,000,000) (115,000,000)
Other Regulatory Assets (Liabilities) | Commodity Contract under FHP    
Derivative    
Unrealized gains/losses on derivatives $ 47,000,000 $ 0
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Mark-to-Market Values of TVA Derivatives (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Derivatives, Fair Value    
Derivative Liability, Fair Value, Gross Liability $ 53  
Derivative, Notional Amount 1,500  
Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value 12 $ 7
250 million Sterling currency swap    
Derivatives, Fair Value    
Fair value (130) (36)
250 million Sterling currency swap | Other long-term liabilities    
Derivatives, Fair Value    
Fair value (123) (32)
250 million Sterling currency swap | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value (7) (4)
150 million Sterling currency swap    
Derivatives, Fair Value    
Fair value (110) (47)
150 million Sterling currency swap | Other long-term liabilities    
Derivatives, Fair Value    
Fair value (105) (44)
150 million Sterling currency swap | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value (5) (3)
$1.0 billion notional interest rate swap    
Derivatives, Fair Value    
Fair value (672) (1,182)
$1.0 billion notional interest rate swap | Other long-term liabilities    
Derivatives, Fair Value    
Fair value (630) (1,101)
$1.0 billion notional interest rate swap | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value (9) (44)
$1.0 billion notional interest rate swap | Interest payable, current    
Derivatives, Fair Value    
Fair value (33) (37)
$476 million notional interest rate swap    
Derivatives, Fair Value    
Fair value (233) (455)
$476 million notional interest rate swap | Other long-term liabilities    
Derivatives, Fair Value    
Fair value (221) (423)
$476 million notional interest rate swap | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value (3) (22)
$476 million notional interest rate swap | Interest payable, current    
Derivatives, Fair Value    
Fair value (9) (10)
$42 million notional interest rate swap    
Derivatives, Fair Value    
Fair value 0 (2)
$42 million notional interest rate swap | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value   (1)
Commodity contract derivatives    
Derivatives, Fair Value    
Fair value 145 247
Commodity contract derivatives | Other long-term assets    
Derivatives, Fair Value    
Fair value   40
Commodity contract derivatives | Other current assets    
Derivatives, Fair Value    
Fair value 172 210
Commodity contract derivatives | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value   (3)
$28 million notional    
Derivatives, Fair Value    
Derivative, Notional Amount 28  
$14 million notional    
Derivatives, Fair Value    
Derivative, Notional Amount 14  
Commodity Contract under FHP    
Derivatives, Fair Value    
Fair value 115 $ 0
Commodity Contract under FHP | Other long-term assets    
Derivatives, Fair Value    
Fair value 68  
Commodity Contract under FHP | Other current assets    
Derivatives, Fair Value    
Fair value 54  
Commodity Contract under FHP | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value (8)  
Commodity Contract under FHP | Accounts Receivable [Member]    
Derivatives, Fair Value    
Fair value 1  
Commodity Contract not under FHP | Other long-term assets    
Derivatives, Fair Value    
Fair value 34  
Commodity Contract not under FHP | Other long-term liabilities    
Derivatives, Fair Value    
Fair value (1)  
Commodity Contract not under FHP | Other current assets    
Derivatives, Fair Value    
Fair value 118  
Commodity Contract not under FHP | Accounts payable and accrued liabilities    
Derivatives, Fair Value    
Fair value $ (6)  
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Currency Swaps Outstanding (Details)
£ in Millions
 12 Months Ended
Sep. 30, 2022
GBP (£)
2001 Currency Swap Contract  
Derivative  
Effective Date of Currency Swap Contract 2001
Associated TVA bond issues currency exposure £ 250
Expiration Date of Swap 2032
Overall effective cost to TVA 6.59%
2003 Currency Swap Contract  
Derivative  
Effective Date of Currency Swap Contract 2003
Associated TVA bond issues currency exposure £ 150
Expiration Date of Swap 2043
Overall effective cost to TVA 4.96%
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Counterparty Credit Risk (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
Customers
Sep. 30, 2021
USD ($)
Derivative    
Receivables from power sales | $ $ 1,899 $ 1,480
Credit of Customers    
Derivative    
Number of customers that represent the percent of sales | Customers 2  
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Offsetting of Derivative Assets (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Letter of Credit    
Offsetting Assets [Line Items]    
Amount of letters of credit outstanding $ 704 $ 1,200
Commodity Contract under FHP    
Offsetting Assets [Line Items]    
Gross Amounts of Recognized Assets, subject to master netting or similar arrangements $ 168  
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Offsetting of Derivative Liabilities (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Offsetting Liabilities [Line Items]    
Gross Amounts of Recognized Liabilities, subject to master netting or similar arrangements $ 53  
Gross Amounts Offset in the Balance Sheet 45  
Total derivatives not subject to master netting or similar arrangement 7 $ 3
Derivative Liability, Subject to Master Netting Arrangement, after Offset 1,160 1,725
Derivative Asset, Subject to Master Netting Arrangement, after Offset 275 250
Commodity contract derivatives 152 250
Derivative Liability, Fair Value of Collateral 68  
Currency Swap    
Offsetting Liabilities [Line Items]    
Derivative Liability, Subject to Master Netting Arrangement, after Offset 240 83 [1]
Interest Rate Contract    
Offsetting Liabilities [Line Items]    
Derivative Liability, Subject to Master Netting Arrangement, after Offset 905 1,639 [1]
Other Contract    
Offsetting Liabilities [Line Items]    
Derivative Asset, Subject to Master Netting Arrangement, after Offset   250
Commodity Contract under FHP    
Offsetting Liabilities [Line Items]    
Derivative Liability, Subject to Master Netting Arrangement, after Offset 8 0
Derivative Asset, Subject to Master Netting Arrangement, after Offset 123 0
Letter of Credit    
Offsetting Liabilities [Line Items]    
Amount of letters of credit outstanding $ 704 $ 1,200
[1] Letters of credit of approximately $704 million and $1.2 billion were posted as collateral at September 30, 2022 and 2021, respectively, to partially secure the liability positions of one of the interest rate swaps in accordance with the collateral requirements for this derivative.
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Other Derivative Instruments (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Derivative    
Forward Contract Derivative Asset, at Fair Value $ 4 $ 2
Fair Value, Inputs, Level 2    
Derivative    
Forward Contract Derivative Asset, at Fair Value $ 4 $ 2
v3.22.2.2
Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Collateral (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Derivative    
Likely collateral obligation increase if downgraded $ 22  
Collateralized Securities [Member]    
Derivative    
Aggregate fair value of derivative instruments with credit-risk related contingent features that were in a liability position 1,200  
Collateral obligations 602  
Letter of Credit    
Derivative    
Amount of letters of credit outstanding $ 704 $ 1,200
v3.22.2.2
Risk Management Activities and Derivative Transactions Counterparty Credit Risk (Details)
 12 Months Ended
Sep. 30, 2022
Derivative  
Two Largest Customer Percentage of Total Operating Revenue 17.00%
Moody's, A1 Rating  
Derivative  
Banking Counterparties Credit Rating A2
Natural Gas Banking Counterparties Credit Rating A1
Moody's, B1 Rating  
Derivative  
Natural Gas Banking Counterparties Credit Rating B1
v3.22.2.2
Fair Value Measurements - Investments (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
Units
Sep. 30, 2021
USD ($)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Long-term Investments $ 3,671 $ 4,053
Balance in the NDT 2,500  
Balance in the ART $ 1,100  
Period of time where the investor contributes capital to an investment in a private partnership - minimum | Units 3  
Period of time where the investor contributes capital to an investment in a private partnership - maximum | Units 4  
Minimum investment period 10 years  
Fair value of gross plan assets $ 8,566 9,749
Number of readily available quoted exchange prices for the investments 0  
LTDCP    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Unrealized gains (losses) on investments $ (5) 1
SERP    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Unrealized gains (losses) on investments (19) 7
ART    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Unrealized gains (losses) on investments (190) 145
NDT    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Unrealized gains (losses) on investments (396) $ 279
Equity Funds [Member]    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Commitments, Fair Value Disclosure 187  
Real Estate Funds [Member]    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Commitments, Fair Value Disclosure 128  
Credit [Member]    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Commitments, Fair Value Disclosure 57  
Defensive growth assets    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Commitments, Fair Value Disclosure 104  
Private real estate funds    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Fair value of gross plan assets 75  
Private Credit [Member]    
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]    
Commitments, Fair Value Disclosure $ 32  
v3.22.2.2
Fair Value Measurements - Nonperformance Risk (Details)
$ in Millions
Sep. 30, 2022
USD ($)
Nonperformance Risk  
Derivative credit valuation adjustment, assets $ (2)
Derivative credit valuation adjustment, liabilities $ 2
v3.22.2.2
Fair Value Measurements - Fair Value Measurements (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Investments    
Government debt securities $ 394 $ 597
Corporate debt securities 283 411
Mortgage and asset-backed securities 52 63
Institutional mutual funds 242 225
Forward debt securities contracts - asset 4 2
Private equity funds measured at net asset value 487 357
Private real estate measured at net asset value 369 272
Private credit measured at net asset value 103 71
Commingled funds measured at net asset value 1,203 1,421
Total investments 3,671 4,053
Commodity contract derivatives 152 250
Total 3,946 4,303
Liabilities    
Currency swaps 240 83 [1]
Interest rate swaps 905 1,639
Commodity contract derivatives 7 3
Total 1,160 1,725
Equity Securities, FV-NI, Noncurrent 534 634
Derivative Liability, Subject to Master Netting Arrangement, after Offset 1,160 1,725
Derivative Asset, Subject to Master Netting Arrangement, after Offset 275 250
Commodity Contract under FHP    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair value 115 0
Liabilities    
Derivative Liability, Subject to Master Netting Arrangement, after Offset 8 0
Derivative Asset, Subject to Master Netting Arrangement, after Offset 123 0
Fair Value, Inputs, Level 1    
Investments    
Government debt securities 358 573
Corporate debt securities 0 0
Mortgage and asset-backed securities 0 0
Institutional mutual funds 242 225
Forward debt securities contracts - asset 0 0
Private equity funds measured at net asset value 0 0
Private real estate measured at net asset value 0 0
Private credit measured at net asset value 0 0
Commingled funds measured at net asset value 0 0
Total investments 1,134 1,432
Commodity contract derivatives 0 0
Total 1,134 1,432
Liabilities    
Currency swaps 0 0
Interest rate swaps 0 0
Commodity contract derivatives 0 0
Total 0 0
Equity Securities, FV-NI, Noncurrent 534 634
Fair Value, Inputs, Level 1 | Commodity Contract under FHP    
Liabilities    
Derivative Liability, Subject to Master Netting Arrangement, after Offset 0  
Derivative Asset, Subject to Master Netting Arrangement, after Offset 0  
Fair Value, Inputs, Level 2    
Investments    
Government debt securities 36 24
Corporate debt securities 283 411
Mortgage and asset-backed securities 52 63
Institutional mutual funds 0 0
Forward debt securities contracts - asset 4 2
Private equity funds measured at net asset value 0 0
Private real estate measured at net asset value 0 0
Private credit measured at net asset value 0 0
Commingled funds measured at net asset value 0 0
Total investments 375 500
Commodity contract derivatives 152 250
Total 650 750
Liabilities    
Currency swaps 240 83
Interest rate swaps 905 1,639
Commodity contract derivatives 7 3
Total 1,160 1,725
Equity Securities, FV-NI, Noncurrent 0 0
Fair Value, Inputs, Level 2 | Commodity Contract under FHP    
Liabilities    
Derivative Liability, Subject to Master Netting Arrangement, after Offset 8  
Derivative Asset, Subject to Master Netting Arrangement, after Offset 123  
Fair Value, Inputs, Level 3    
Investments    
Government debt securities 0 0
Corporate debt securities 0 0
Mortgage and asset-backed securities 0 0
Institutional mutual funds 0 0
Forward debt securities contracts - asset 0 0
Private equity funds measured at net asset value 0 0
Private real estate measured at net asset value 0 0
Private credit measured at net asset value 0 0
Commingled funds measured at net asset value 0 0
Total investments 0 0
Commodity contract derivatives 0 0
Total 0 0
Liabilities    
Currency swaps 0 0
Interest rate swaps 0 0
Commodity contract derivatives 0 0
Total 0 0
Equity Securities, FV-NI, Noncurrent 0 $ 0
Fair Value, Inputs, Level 3 | Commodity Contract under FHP    
Liabilities    
Derivative Liability, Subject to Master Netting Arrangement, after Offset 0  
Derivative Asset, Subject to Master Netting Arrangement, after Offset $ 0  
[1] See Note 15 — Risk Management Activities and Derivative Transactions — Offsetting of Derivative Assets and Liabilities.
v3.22.2.2
Fair Value Measurements - Fair Value Measurements Using Significant Unobservable Inputs (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Fair Value Measurements    
Commodity contract derivatives, assets $ 152 $ 250
Commodity contract derivatives, liabilities 7 3
Fair Value, Inputs, Level 3    
Fair Value Measurements    
Commodity contract derivatives, assets 0 0
Commodity contract derivatives, liabilities $ 0 $ 0
v3.22.2.2
Fair Value Measurements - Estimated Values of Financial Instruments (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Estimated Values of Financial Instruments (Level 2 Valuation)    
EnergyRight receivables (including current portion) $ 62 $ 71
Financing Receivable, after Allowance for Credit Loss 96 94
EnergyRight® financing obligations (including current portion) 81 92
Unfunded Loan Commitments 0 3
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount 22 30
Long-term outstanding power bonds (including current maturities), net 18,070 24,309
Long-term debt of variable interest entities (including current maturities) 989 1,307
Portion at Other than Fair Value Measurement [Member]    
Estimated Values of Financial Instruments (Level 2 Valuation)    
EnergyRight receivables (including current portion) 62 72
Financing Receivable, after Allowance for Credit Loss 105 99
EnergyRight® financing obligations (including current portion) 72 82
Unfunded Loan Commitments 0 0
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount 20 23
Long-term outstanding power bonds (including current maturities), net 17,856 18,485
Long-term debt of variable interest entities (including current maturities) $ 1,007 $ 1,049
v3.22.2.2
Proprietary Capital (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Appropriation Investment      
Amount of appropriation investment that was repaid $ 1,000    
Balance at beginning of year 14,465 $ 12,932 $ 11,625
Net income (loss) 1,108 1,512 1,352
Return on power program appropriation investment (4) (4) (6)
Balance at end of year 15,505 14,465 $ 12,932
Net proprietary capital at September 30 $ 15,505 $ 14,465  
Computed average interest rate payable 1.47% 1.64% 2.44%
Power Program Appropriation Investment      
Appropriation Investment      
Balance at beginning of year $ 258 $ 258 $ 258
Net income (loss) 0 0 0
Return on power program appropriation investment 0 0 0
Balance at end of year 258 258 258
New Accounting Standard - CECL   0  
Power Program Retained Earnings      
Appropriation Investment      
Balance at beginning of year 13,689 12,177 10,823
Net income (loss) 1,115 1,520 1,360
Return on power program appropriation investment (4) (4) (6)
Balance at end of year 14,800 13,689 12,177
New Accounting Standard - CECL   (4)  
Nonpower Programs Appropriation Investment, Net      
Appropriation Investment      
Balance at beginning of year 540 548 556
Net income (loss) (7) (8) (8)
Return on power program appropriation investment 0 0 0
Balance at end of year 533 540 548
New Accounting Standard - CECL   0  
Affiliated Entity      
Appropriation Investment      
Return on power program appropriation investment $ (4) $ (4) $ (6)
v3.22.2.2
Proprietary Capital - Accumulated Other Comprehensive Income (Loss) (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
Accumulated Other Comprehensive Income (Loss)  
Reclassification to earnings from cash flow hedges in the next twelve months $ (29)
v3.22.2.2
Other Income (Expense), Net Other Income (Expense), Net (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Other Income (Expense), Net      
Other income $ 0 $ 28 $ 0
Interest income 15 12 18
External services 16 13 12
Gain (Loss) on Investments (17) 16 9
Miscellaneous (7) 0 (3)
Other income (expense), net $ 7 $ 13 $ 36
v3.22.2.2
Benefit Plans Components of Benefit Plans (Details) - USD ($)
 12 Months Ended
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Defined Benefit Plan Disclosure        
Fixed and variable fund annual maximum contribution   $ 10,000    
Defined contribution plan contribution amount   $ 97,000,000 $ 92,000,000 $ 88,000,000
Minimum        
Defined Benefit Plan Disclosure        
Threshold for Deferral of Actuarial Gain/Loss Under Corridor Approach   10.00%    
Scenario, Forecast        
Defined Benefit Plan Disclosure        
Defined contribution plan contribution amount $ 101,000,000      
v3.22.2.2
Benefit Plans Obligations and Funded Status (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Pension Benefits      
Change in benefit obligation      
Benefit obligation $ 13,348 $ 13,675  
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation 10,536 13,348  
Service cost 53 57 $ 55
Plan participants' contributions 5 5  
Change in Plan Assets due to Collections 0 0  
Collections [1] 0 0  
Actuarial loss (gain) (2,509) (25)  
Net transfers from variable fund/401(k) plan 11 2  
Expenses paid (6) (6)  
Benefits paid 744 728  
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets 8,094 9,110  
Change in plan assets      
Fair value of net plan assets 9,110 7,959  
Actual return on plan assets (590) 1,572  
Employer contributions 308 306  
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]      
Funded status $ (2,442) $ (4,238)  
Discount rate 5.60% 2.90% 2.75%
Amount of defined benefit plan actuarial gain (loss) from discount rate change $ (3,500) $ (248)  
Amount of defined benefit plan actuarial gain (loss) from change in mortality assumption (527) (28)  
Amount of defined benefit plan actuarial gain (loss) from change in demograhic and plan experience 78 104  
Amount of defined benefit plan actuarial gain (loss) from assumption change in elections 411 91  
Other Post-retirement Benefits      
Change in benefit obligation      
Benefit obligation 388 498  
Postconfirmation, Other Postretirement Obligations 498 544  
Service cost 17 18 $ 16
Plan participants' contributions 0 0  
Change in Plan Assets due to Collections 15 17  
Collections [1] 15 17  
Actuarial loss (gain) (114) (53)  
Net transfers from variable fund/401(k) plan 0 0  
Expenses paid 0 0  
Benefits paid 43 44  
Change in plan assets      
Fair value of net plan assets 0 0  
Actual return on plan assets 0 0  
Employer contributions 28 27  
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]      
Funded status $ (388) $ (498)  
Discount rate 5.65% 3.05%  
Amount of defined benefit plan actuarial gain (loss) from updated capita claims costs and retiree contributions   $ (47)  
Amount of change related to actual   1  
Amount of defined benefit plan actuarial gain (loss) from change in demograhic and plan experience   $ 7  
[1] Collections include retiree contributions as well as provider discounts and rebates.
v3.22.2.2
Benefit Plans Amounts Recognized on TVA's Consolidated Balance Sheets (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Defined Benefit Plan Disclosure      
Regulatory assets $ (6,134) $ (7,956)  
Non-current regulatory liabilities (172) (40)  
Accounts payable and accrued liabilities (2,466) (2,215)  
Pension and post-retirement benefit obligations (3,072) (5,045)  
Postemployment benefits liability, noncurrent 299    
Pension Benefits      
Defined Benefit Plan Disclosure      
Amount capitalized due to actions of regulator 77 91  
Regulatory assets (1,839) (3,636)  
Accounts payable and accrued liabilities (6) (7)  
Pension and post-retirement benefit obligations [1] (2,436) (4,231)  
Other Post-retirement Benefits      
Defined Benefit Plan Disclosure      
Amount capitalized due to actions of regulator 0 0  
Regulatory assets (70) (32)  
Non-current regulatory liabilities (70)    
Accounts payable and accrued liabilities (22) (24)  
Pension and post-retirement benefit obligations [1] (366) (474)  
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent      
Defined Benefit Plan Disclosure      
Postemployment benefits liability, noncurrent $ 270 $ 340 $ 390
[1] The table above excludes $270 million and $340 million of post-employment benefit costs that are recorded in Post-retirement and post-employment benefit obligations on the Consolidated Balance Sheets at September 30, 2022 and 2021, respectively.
v3.22.2.2
Benefit Plans Postretirement Benefit Costs Deferred as Regulatory Assets (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Defined Benefit Plan Disclosure    
Regulatory assets $ (6,134) $ (7,956)
Non-current regulatory liabilities 172 40
Pension Benefits    
Defined Benefit Plan Disclosure    
Unrecognized prior service cost (credit) (424) (517)
Unrecognized net loss 2,186 4,062
Amount capitalized due to actions of regulator (77) (91)
Regulatory assets (1,839) (3,636)
Other Post-retirement Benefits    
Defined Benefit Plan Disclosure    
Unrecognized prior service cost (credit) (76) (93)
Unrecognized net loss 6 125
Amount capitalized due to actions of regulator 0 0
Regulatory assets (70) $ (32)
Non-current regulatory liabilities $ 70  
v3.22.2.2
Benefit Plans Projected Benefit Obligations and Accumulated Benefit Obligations in Exess of Plan Assets (Details) - Pension Benefits - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Defined Benefit Plan Disclosure    
Accumulated benefit obligation $ 10,508 $ 13,299
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets 8,094 9,110
Fair value of net plan assets $ 9,110 $ 7,959
v3.22.2.2
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
v3.22.2.2
Benefit Plans Actuarial Assumptions (Details) - USD ($)
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2024
Sep. 30, 2023
Defined Benefit Plan Disclosure          
Defined Benefit Plan, Cost of Living Adjustment Assumption 0.25%        
Pension Benefits          
Defined Benefit Plan Disclosure          
Discount rate 2.90% 2.75% 3.20%    
Discount rate 5.60% 2.90% 2.75%    
Rate of compensation increase 3.32% 3.37%      
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate 5.14% 5.15%      
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Weighted-Average Interest Crediting Rate 5.14% 5.15% 5.15%    
Expected return on plan assets 5.75% 6.75% 6.75%    
Defined Benefit Plan, Cost of Living Adjustment Assumption 2.00% 2.00% 2.00%    
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase   3.37% 3.43%    
COLA percentage increase (decrease) 6.00%        
Actual Return on Plan Assets (6.64%) 20.30% 5.11%    
Other Post-retirement Benefits          
Defined Benefit Plan Disclosure          
Discount rate 3.05% 3.05% 3.30%    
Discount rate 5.65% 3.05%      
Defined Benefit Plan, Cost of Living Adjustment Assumption 2.00% 2.00% 2.00%    
Minimum          
Defined Benefit Plan Disclosure          
Rate of compensation increase 2.50%        
Maximum          
Defined Benefit Plan Disclosure          
Rate of compensation increase 14.00%        
Scenario, Forecast | Pension Benefits          
Defined Benefit Plan Disclosure          
Defined Benefit Plan, Cost of Living Adjustment Assumption Next Fiscal Year       315.00% 6.00%
Post-Medicare Eligible [Member] [Member] | Other Post-retirement Benefits          
Defined Benefit Plan Disclosure          
Current health care cost trend rate 0.00% 0.00% 0.00%    
Ultimate health care cost trend rate 4.00% 4.00% 4.00%    
Year health care cost ultimate trend rate is reached for Net Benefit Cost Assumption 2024 2024 2023    
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate 2026 2024      
Pre-Medicare Eligible per Capita Claim Costs | Other Post-retirement Benefits          
Defined Benefit Plan Disclosure          
Current health care cost trend rate 6.25% 6.50% 6.75%    
Ultimate health care cost trend rate 5.00% 5.00% 5.00%    
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate 2031 2027 2027    
Initial health care cost trend rate $ 0.0700 $ 0.0625      
Pre-Medicare Eligible per Capita Claim Costs | Pension Costs [Member]          
Defined Benefit Plan Disclosure          
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate 2027        
Pre-Medicare Eligible per Capita Contributions | Other Post-retirement Benefits          
Defined Benefit Plan Disclosure          
Current health care cost trend rate 8.51% 11.93% 6.75%    
Ultimate health care cost trend rate 5.00% 5.00% 5.00%    
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate 2022 2027 2027    
Initial health care cost trend rate $ 0.0500 $ 0.0851      
Pre-Medicare Eligible per Capita Contributions | Pension Costs [Member]          
Defined Benefit Plan Disclosure          
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate 2027        
v3.22.2.2
Benefit Plans Sensitivity to Certain Changes in Pension Assumptions (Details) - USD ($)
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Defined Benefit Plan Disclosure      
Defined Benefit Plan, Cost of Living Adjustment Assumption 0.25%    
Discount rate      
Defined Benefit Plan Disclosure      
Change in Assumption (0.25%)    
Impact on Pension Cost $ 16,000,000    
Impact on Projected Benefit Obligation $ 257,000,000    
Rate of return on plan assets      
Defined Benefit Plan Disclosure      
Change in Assumption (0.25%)    
Impact on Pension Cost $ 19,000,000    
Cost of Living Adjustments [Domain]      
Defined Benefit Plan Disclosure      
Change in Assumption 0.25%    
Impact on Pension Cost $ 29,000,000    
Impact on Projected Benefit Obligation $ 179,000,000    
Other Post-retirement Benefits      
Defined Benefit Plan Disclosure      
Defined Benefit Plan, Cost of Living Adjustment Assumption 2.00% 2.00% 2.00%
Discount rate 5.65% 3.05%  
Actuarial assumption COLA $ 0.035 $ 0.0113 $ 0.0154
Pension Benefits      
Defined Benefit Plan Disclosure      
Defined Benefit Plan, Cost of Living Adjustment Assumption 2.00% 2.00% 2.00%
COLA percentage increase (decrease) 6.00%    
Discount rate 5.60% 2.90% 2.75%
v3.22.2.2
Benefit Plans Asset Holdings (Details) - USD ($)
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Defined Benefit Plan Disclosure      
Target Allocation 100.00%    
Plan Asset Allocations 100.00% 100.00%  
Growth Assets      
Defined Benefit Plan Disclosure      
Target Allocation 17.00%    
Plan Asset Allocations 20.00% 18.00%  
Defensive growth assets      
Defined Benefit Plan Disclosure      
Target Allocation 38.00%    
Plan Asset Allocations 34.00% 35.00%  
Defensive Assets      
Defined Benefit Plan Disclosure      
Target Allocation 20.00%    
Plan Asset Allocations 18.00% 20.00%  
Inflation-sensitive Assets      
Defined Benefit Plan Disclosure      
Target Allocation 25.00%    
Plan Asset Allocations 28.00% 27.00%  
Other Post-retirement Benefits      
Defined Benefit Plan Disclosure      
Actuarial assumption COLA $ 0.035 $ 0.0113 $ 0.0154
v3.22.2.2
Benefit Plans Fair Value Measurements (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
Years
Sep. 30, 2021
USD ($)
Oct. 01, 2019
USD ($)
Defined Benefit Plan Disclosure      
Fair value of gross plan assets $ 8,566 $ 9,749  
Derivative liabilities 176 136  
Net payables 100 263  
Payables for collateral on loaned securities $ 196 240  
Voting percentage required to desolve partnership in private equity 80.00%    
Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets $ 1,916 2,898  
Derivative liabilities 10 4  
Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 2,328 2,755  
Derivative liabilities 166 132  
Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 62 74 $ 94
Derivative liabilities 0 0  
Equity securities      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 709 992  
Equity securities | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 707 990  
Equity securities | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Equity securities | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 2 2  
Preferred securities      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 6 9  
Preferred securities | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 1 2  
Preferred securities | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 5 6  
Preferred securities | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 1  
Corporate debt securities      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 1,087 1,360  
Corporate debt securities | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Corporate debt securities | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 1,087 1,359  
Corporate debt securities | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 1  
Residential mortgage-backed securities      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 293 275  
Residential mortgage-backed securities | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Residential mortgage-backed securities | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 289 267  
Residential mortgage-backed securities | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 4 8  
Debt securities issued by U.S. Treasury and other U.S. government agencies      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 616 741  
Debt securities issued by U.S. Treasury and other U.S. government agencies | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 616 741  
Debt securities issued by U.S. Treasury and other U.S. government agencies | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Debt securities issued by U.S. Treasury and other U.S. government agencies | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Asset-backed securities      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 176 151  
Asset-backed securities | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Asset-backed securities | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 136 110  
Asset-backed securities | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 40 41  
Debt securities issued by state/local governments      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 23 28  
Debt securities issued by state/local governments | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Debt securities issued by state/local governments | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 23 28  
Debt securities issued by state/local governments | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Debt securities issued by foreign governments      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 130 204  
Debt securities issued by foreign governments | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Debt securities issued by foreign governments | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 130 200  
Debt securities issued by foreign governments | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 4  
Commercial mortgage-backed securities      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 161 168  
Commercial mortgage-backed securities | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Commercial mortgage-backed securities | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 145 151  
Commercial mortgage-backed securities | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 16 17  
Equity security commingled funds      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 436 619  
Equity security commingled funds | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Equity security commingled funds | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Equity security commingled funds | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Debt security commingled funds      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 657 881  
Debt security commingled funds | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Debt security commingled funds | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Debt security commingled funds | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Blended security commingled funds      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 111 105  
Blended security commingled funds | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Blended security commingled funds | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Blended security commingled funds | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Institutional mutual funds      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 454 841  
Institutional mutual funds | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 454 841  
Institutional mutual funds | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Institutional mutual funds | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Cash equivalents and other short-term investments      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 431 710  
Cash equivalents and other short-term investments | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 133 323  
Cash equivalents and other short-term investments | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 298 387  
Cash equivalents and other short-term investments | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private Credit [Member]      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 522 324  
Private Credit [Member] | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private Credit [Member] | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private Credit [Member] | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private equity funds measured at net asset value      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 1,454 1,333  
Private equity funds measured at net asset value | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private equity funds measured at net asset value | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private equity funds measured at net asset value | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private real estate funds      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 1,080 760  
Private real estate funds | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private real estate funds | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Private real estate funds | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Securities lending commingled funds      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 196 240  
Securities lending commingled funds | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Securities lending commingled funds | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 196 240  
Securities lending commingled funds | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Futures      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 5 1  
Derivative liabilities 10 4  
Futures | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 5 1  
Derivative liabilities 10 4  
Futures | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Derivative liabilities 0 0  
Futures | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Derivative liabilities 0 0  
Purchased options      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 17 6  
Purchased options | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Purchased options | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 17 6  
Purchased options | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Interest Rate Swap      
Defined Benefit Plan Disclosure      
Derivative liabilities 54 23  
Interest Rate Swap | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Derivative liabilities 0 0  
Interest Rate Swap | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Derivative liabilities 54 23  
Interest Rate Swap | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Derivative liabilities 0 0  
Foreign currency forward      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 2 1  
Derivative liabilities 1 1  
Foreign currency forward | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Derivative liabilities 0 0  
Foreign currency forward | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 2 1  
Derivative liabilities 1 1  
Foreign currency forward | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Fair value of gross plan assets 0 0  
Derivative liabilities 0 0  
Securities Sold under Agreements to Repurchase [Member]      
Defined Benefit Plan Disclosure      
Derivative liabilities 111 108  
Securities Sold under Agreements to Repurchase [Member] | Fair Value, Inputs, Level 1      
Defined Benefit Plan Disclosure      
Derivative liabilities 0 0  
Securities Sold under Agreements to Repurchase [Member] | Fair Value, Inputs, Level 2      
Defined Benefit Plan Disclosure      
Derivative liabilities 111 108  
Securities Sold under Agreements to Repurchase [Member] | Fair Value, Inputs, Level 3      
Defined Benefit Plan Disclosure      
Derivative liabilities $ 0 $ 0  
Minimum      
Defined Benefit Plan Disclosure      
Number of years partnerships in private equity generally continue | Years 10    
Number of one year extensions for partnerships in private equity | Years 2    
Maximum      
Defined Benefit Plan Disclosure      
Number of years partnerships in private equity generally continue | Years 14    
Number of one year extensions for partnerships in private equity | Years 3    
v3.22.2.2
Benefit Plans Fair Value Measurements Using Significant Unobservable Inputs (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Oct. 01, 2019
Defined Benefit Plan Disclosure      
Net payables $ 100 $ 263  
Payables for collateral on loaned securities 196 240  
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]      
Fair value of gross plan assets 8,566 9,749  
Fair Value, Inputs, Level 3      
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]      
Fair value of gross plan assets 62 74 $ 94
Net realized/unrealized gains (4) (48)  
Purchases, sales, issuances, and settlements, net 2 32  
Transfers in and/or out of Level 3 (10) $ (4)  
Fair value of net plan assets $ 62    
v3.22.2.2
Benefit Plans Estimated Future Benefit Payments (Details)
$ in Millions
Sep. 30, 2022
USD ($)
Pension Benefits  
Defined Benefit Plan Disclosure  
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months $ 793
Defined Benefit Plan, Expected Future Benefit Payments, Year Two 808
Defined Benefit Plan, Expected Future Benefit Payments, Year Three 813
Defined Benefit Plan, Expected Future Benefit Payments, Year Four 810
Defined Benefit Plan, Expected Future Benefit Payments, Year Five 807
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter 3,932
Other Post-retirement Benefits  
Defined Benefit Plan Disclosure  
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months 22
Defined Benefit Plan, Expected Future Benefit Payments, Year Two 21
Defined Benefit Plan, Expected Future Benefit Payments, Year Three 21
Defined Benefit Plan, Expected Future Benefit Payments, Year Four 21
Defined Benefit Plan, Expected Future Benefit Payments, Year Five 22
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter $ 126
v3.22.2.2
Benefit Plans Contributions (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2023
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Defined Benefit Plan Disclosure        
Defined contribution plan contribution amount   $ 97 $ 92 $ 88
Other postretirement benefit contributions   28 25  
Contribution related to TVARS case   4 5  
Supplemental Employee Retirement Plans, Defined Benefit        
Defined Benefit Plan Disclosure        
Defined Benefit Plan, Related to SERP   8 6  
Other Post-retirement Benefits        
Defined Benefit Plan Disclosure        
Employer contributions   28 27  
Pension Benefits        
Defined Benefit Plan Disclosure        
Employer contributions   308 $ 306  
Other Pension Plans, Defined Benefit        
Defined Benefit Plan Disclosure        
Employer contributions   300    
Minimum | Other Pension Plans, Defined Benefit        
Defined Benefit Plan Disclosure        
Employer contributions   $ 300    
Scenario, Forecast        
Defined Benefit Plan Disclosure        
Defined contribution plan contribution amount $ 101      
Scenario, Forecast | Other Pension Plans, Defined Benefit        
Defined Benefit Plan Disclosure        
Employer contributions $ 300      
v3.22.2.2
Benefit Plans Other Postemployment Benefits (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Other Post-Employment Benefits      
Discount rate 3.83% 1.52% 0.69%
Period expense $ (40) $ (20) $ (45)
Postemployment benefits liability, noncurrent 299    
Accounts Payable and Accrued Liabilities      
Other Post-Employment Benefits      
Postemployment Benefits Liability, Current 29 0  
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent      
Other Post-Employment Benefits      
Postemployment benefits liability, noncurrent $ 270 $ 340 $ 390
v3.22.2.2
Commitments and Contingencies - Table (Details)
$ in Millions
Sep. 30, 2022
USD ($)
megawatts
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Obligations      
Megawatts provided under transmission obligations | megawatts 2,450    
Accrual for Environmental Loss Contingencies, Gross $ 17 $ 18  
Estimated future decommissioning cost [1] 7,162 7,002 $ 6,785
CT and QTE outstanding leaseback obligation   25  
Nuclear      
Obligations      
Estimated future decommissioning cost $ 3,643 $ 3,428 $ 3,278
[1]
(1) Includes $275 million and $266 million at September 30, 2022 and 2021, respectively, in Current liabilities.
(2) Settlements include the change in asset retirement obligation project accruals included in Accounts payable and accrued liabilities of $20 million.
v3.22.2.2
Commitments and Contingencies - Membership Interests of VIE Subject to Mandatory Redemption (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Portion at Other than Fair Value Measurement [Member]    
Long-term Purchase Commitment [Line Items]    
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount $ 20 $ 23
Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount 22 $ 30
Minimum payments on membership interests subject to mandatory redemption, due in next twelve months 2  
Minimum payments on membership interests subject to mandatory redemption, due in year two 1  
Minimum payments on membership interests subject to mandatory redemption, due in year three 1  
Minimum payments on membership interests subject to mandatory redemption, due in year four 1  
Minimum payments on membership interests subject to mandatory redemption, due in year five $ 1  
v3.22.2.2
Commitments and Contingencies - Leases (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Leases      
CT and QTE outstanding leaseback obligation   $ 25  
Estimated future decommissioning cost [1] $ 7,162 $ 7,002 $ 6,785
[1]
(1) Includes $275 million and $266 million at September 30, 2022 and 2021, respectively, in Current liabilities.
(2) Settlements include the change in asset retirement obligation project accruals included in Accounts payable and accrued liabilities of $20 million.
v3.22.2.2
Commitments and Contingencies - Purchase Obligations (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
Megawatts
megawatts
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Sep. 30, 2028
USD ($)
Sep. 30, 2027
USD ($)
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2024
USD ($)
Sep. 30, 2023
USD ($)
Obligations                  
Megawatts provided under power purchase obligations | Megawatts 3,949                
Remaining terms of the agreements, high end of range 13 years                
Megawatts provided under transmission obligations | megawatts 2,450                
Power purchased under agreement | $ $ 318 $ 202 $ 202            
2019 | $ $ 0                
Scenario, Forecast                  
Obligations                  
Purchase Obligation | $       $ 766 $ 145 $ 145 $ 145 $ 145 $ 146
Purchase Agreements Required by Federal Law                  
Obligations                  
Megawatts provided under power purchase obligations | Megawatts 278                
Number of generation sources under PPAs | Megawatts 642                
v3.22.2.2
Commitments and Contingencies - Contingencies (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
Insurance_layers
reactors
Units
Procedures
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Contingencies      
Loss Contingency, Damages Sought, Value $ 30    
Nuclear liability insurance 450    
Assessment from licensees for each licensed reactor $ 138    
Number of licensed reactors in US | reactors 96    
Nuclear accident assessment limitation per year per unit $ 20    
Number of licensed nuclear units | Units 7    
Maximum assessment per nuclear incident $ 963    
Total amount of protection available $ 13,700    
Number of layers until the U.S. Congress is required to take action | Insurance_layers 2    
Amount of insurance available for loss at any one site $ 2,100    
Maximum amount of retrospective premiums 115    
Maximum idemnity if a covered accident tasks or keeps a nuclear unit offline 490    
Maximum amount of retrospective premiums 44    
Estimated future decommissioning cost [1] $ 7,162 $ 7,002 $ 6,785
Number of procedures for determining estimates for the costs of nuclear decommissioning | Procedures 2    
Amount spent to reduce emissions since 1970 $ 6,800    
Amount spent to reduce emissions 16 17 19
Possible additional future costs for compliance with Clean Air Act requirements 128    
Possible additional future costs for compliance with CCR requirements 900    
Possible additional future costs for compliance with Clean Water requirements. 111    
Estimated liability for cleanup and similar environmental work on a non-discounted basis 17 18  
Amount of insurance available for loss at any one site, max 2,800    
Nuclear      
Contingencies      
Estimated future decommissioning cost 3,643 3,428 3,278
Non-nuclear      
Contingencies      
Estimated future decommissioning cost $ 3,519 $ 3,574 $ 3,507
[1]
(1) Includes $275 million and $266 million at September 30, 2022 and 2021, respectively, in Current liabilities.
(2) Settlements include the change in asset retirement obligation project accruals included in Accounts payable and accrued liabilities of $20 million.
v3.22.2.2
Commitments and Contingencies - Legal Proceedings (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Legal Proceedings    
Possible additional future costs for compliance with CCR requirements $ 900  
Contribution related to TVARS case 4 $ 5
Possible additional future costs for compliance with Clean Water requirements. 111  
Amount remaining to be spent under environmental agreements 9  
Loss Contingency, Damages Sought, Value 30  
Down payment from Nuclear Development 22  
Compensated costs to Nuclear Development 1  
General    
Legal Proceedings    
Legal loss contingency accrual 11  
Environmental Agreements    
Legal Proceedings    
Amount to be invested in certain environmental projects 290  
Amount invested in certain environmental projects 282  
Other long-term liabilities | General    
Legal Proceedings    
Legal loss contingency accrual 10  
Accounts payable and accrued liabilities | General    
Legal Proceedings    
Legal loss contingency accrual $ 1  
v3.22.2.2
Commitments and Contingencies Unfunded loan commitments (Details)
$ in Millions
Sep. 30, 2022
USD ($)
Other commitments - unfunded loan commitments [Abstract]  
2019 $ 0
2020 $ 0
v3.22.2.2
Related Parties Related Parties (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Related Parties      
Revenue from sales of electricity $ 12,540 $ 10,503 $ 10,249
Other income 0 (28) 0
Long-term Investments 3,671 4,053  
Return on power program appropriation investment (4) (4) (6)
Related Party Transactions      
Related Parties      
Revenue from sales of electricity 134 109 105
Other income 296 280 260
Operating expenses 228 214 224
Additions to property, plant, and equipment 11 10 9
Cash and cash equivalents 30 30 31
Receivables from Customers 78 65 94
Long-term Investments 358 573 485
Receivables, Long-term Contracts or Programs 43 31 27
Accounts payable and accrued liabilities 42 15 39
Long-term power bonds, net 1 1 1
Return on power program appropriation investment $ (4) $ (4) $ (6)
v3.22.2.2
Unaudited Quarterly Financial Information Unaudited Quarterly Financial Information (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Quarterly Financial Information Disclosure [Abstract]      
Revenue from sales of electricity $ 12,540 $ 10,503 $ 10,249
Operating expenses 10,129 7,658 7,538
Operating income 2,411 2,845 2,711
Net income (loss) $ 1,108 $ 1,512 $ 1,352
v3.22.2.2
Revenue (Details) - USD ($)
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Other revenue $ 169,000,000 $ 146,000,000 $ 145,000,000
Off-system sales 19,000,000 7,000,000 4,000,000
Sales of Electricity (subtotal) 12,352,000,000 10,350,000,000 10,100,000,000
Electric revenue (12,371,000,000) (10,357,000,000) (10,104,000,000)
Revenues 12,540,000,000 10,503,000,000 10,249,000,000
Pandemic Relief Credit (228,000,000) (221,000,000)  
Revenue Not from Contract with Customer $ 0.015    
Revenue from Contract with Customer [Abstract]      
Percent of Pandemic Credit Offered 2.50%    
ALABAMA      
Electric revenue $ (1,778,000,000) (1,508,000,000) (1,439,000,000)
GEORGIA      
Electric revenue (299,000,000) (254,000,000) (249,000,000)
KENTUCKY      
Electric revenue (821,000,000) (655,000,000) (624,000,000)
MISSISSIPPI      
Electric revenue (1,182,000,000) (984,000,000) (941,000,000)
NORTH CAROLINA      
Electric revenue (87,000,000) (66,000,000) (65,000,000)
TENNESSEE      
Electric revenue (8,137,000,000) (6,841,000,000) (6,740,000,000)
VIRGINIA      
Electric revenue $ (48,000,000) $ (42,000,000) $ (42,000,000)
v3.22.2.2
Revenue Customer Type (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2023
USD ($)
Sep. 30, 2022
USD ($)
Units
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Electric revenue   $ 12,371 $ 10,357 $ 10,104
Other revenue   169 146 145
Revenues   12,540 10,503 10,249
Bill credits for LTA   $ (199) (189) 163
Number of LPCs signed LTA | Units   147    
Percentage of total operating revenues   90.00%    
Total number of LPCs | Units   153    
Off-system sales   $ 19 7 4
Percent of sales of electricity to LPCs   91.00%    
Pandemic Relief Credit   $ (228) (221)  
MLGW's % of operating revenues   9.00%    
NES's % of operating revenues   8.00%    
Scenario, Forecast        
Pandemic Relief Credit $ 230      
20-year contract arrangement [Member]        
Percentage of total operating revenues   77.10%    
5-year contract arrangement [Member]        
Number of LPCs signed LTA | Units   6    
Percentage of total operating revenues   12.90%    
TENNESSEE        
Electric revenue   $ 8,137 6,841 6,740
VIRGINIA        
Electric revenue   48 42 42
NORTH CAROLINA        
Electric revenue   87 66 65
MISSISSIPPI        
Electric revenue   1,182 984 941
KENTUCKY        
Electric revenue   821 655 624
GEORGIA        
Electric revenue   299 254 249
ALABAMA        
Electric revenue   1,778 1,508 1,439
Federal agencies and other [Member]        
Electric revenue   154 116 110
20-year contract arrangement [Member]        
Electric revenue   9,670    
5-year contract arrangement [Member]        
Electric revenue   1,621    
Local Power Company [Member]        
Electric revenue   11,291 9,534 9,406
Industries Directly Served [Member]        
Electric revenue   $ 926 $ 707 $ 588
v3.22.2.2
Revenue Local Power Company Contracts (Details)
$ in Millions
 12 Months Ended
Sep. 30, 2022
USD ($)
Units
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Number of LPCs signed LTA | Units 147    
Electric revenue $ 12,371 $ 10,357 $ 10,104
Total number of LPCs | Units 153    
Percentage of total operating revenues 90.00%    
Percent of wholesale Credit offered 3.10%    
20-year contract arrangement [Member]      
Electric revenue $ 9,670    
5-year contract arrangement [Member]      
Electric revenue 1,621    
Local Power Company [Member]      
Electric revenue $ 11,291 $ 9,534 $ 9,406
5-year contract arrangement [Member]      
Number of LPCs signed LTA | Units 6    
Percentage of total operating revenues 12.90%    
v3.22.2.2
Revenue Economic Development Incentives (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Revenue from Contract with Customer [Abstract]      
Revenues $ 328 $ 315 $ 318
Unpaid economic incentives $ 187 $ (176)  
v3.22.2.2
Subsequent Events (Details) - USD ($)
$ in Millions
Nov. 14, 2022
Sep. 30, 2022
Sep. 30, 2021
Debt Instrument, Redemption [Line Items]      
Non-current regulatory liabilities   $ 172 $ 40
Regulatory assets   6,134 7,956
Unrealized gains/losses on commodity derivatives      
Debt Instrument, Redemption [Line Items]      
Non-current regulatory liabilities   $ 102 $ 40
Scenario, Forecast      
Debt Instrument, Redemption [Line Items]      
Increase/Decrease in Interest Rate Swap Liability $ 120    
Scenario, Forecast | Unrealized gains/losses on commodity derivatives      
Debt Instrument, Redemption [Line Items]      
Regulatory assets 2    
Scenario, Forecast | DeferredDerivativeGainLossUnderFHP      
Debt Instrument, Redemption [Line Items]      
Regulatory assets 27    
Scenario, Forecast | Unrealized gains/losses on commodity derivatives      
Debt Instrument, Redemption [Line Items]      
Non-current regulatory liabilities 48    
Scenario, Forecast | DeferredDerivativeGainLossUnderFHP      
Debt Instrument, Redemption [Line Items]      
Non-current regulatory liabilities $ 50    
v3.22.2.2
Plant Closures (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Property, Plant and Equipment [Abstract]      
Accelerated depreciation $ 140 $ 136 $ 125
Completed Plant      
Accelerated depreciation 140 136 125
Property, Plant, and Equipment, Owned, Accumulated Depreciation 482    
Depreciation 1,800 $ 1,400 $ 1,600
Additional depreciation for coal-fired fleet      
Completed Plant      
Depreciation $ 339    
Property, Plant and Equipment [Member]      
Completed Plant      
Property, Plant and Equipment, Dispositions 22 million 4 million 13 million
v3.22.2.2
Leases (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Lessee, Lease, Description [Line Items]      
Operating Lease, Right-of-Use Asset $ 155 $ 165  
Finance lease, Right-of-Use-Asset 630 692  
Total lease assets 785 857  
Operating Lease, Liability, Noncurrent 93 122  
Finance Lease, Liability, Noncurrent 628 687  
Total lease liabilities 839 909  
Operating Lease, Cost 56 52 $ 84
Variable Lease, Cost 78 75 75
Short-term Lease, Cost 26 12 7
Finance Lease, Right-of-Use Asset, Amortization 58 51 15
Finance Lease, Interest Expense 42 39 33
Total finance lease costs 100 90 48
Lease, Cost 260 229 $ 214
Derivative, Notional Amount 1,500    
Operating lease liability      
Lessee, Lease, Description [Line Items]      
Accounts Payable and Accrued Liabilities 59 40  
Finance lease liability      
Lessee, Lease, Description [Line Items]      
Accounts Payable and Accrued Liabilities $ 59 $ 60  
v3.22.2.2
Leases, SoCF (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Lessee, Lease, Description [Line Items]      
Operating cash flows for operating leases $ 57 $ 53 $ 85
Operating cash flows for finance leases 42 39 33
Financing cash flows for finance leases 60 52 15
Lease assets obtained in exchange for lease obligations - finance 0 233 394
Lease assets obtained in exchange for lease obligations - operating $ 43 $ (22) $ 110
v3.22.2.2
Leases, Weighted Averages (Details)
Sep. 30, 2022
Sep. 30, 2021
Lessee, Lease, Description [Line Items]    
Operating Lease, Weighted Average Remaining Lease Term 3 years 5 years
Finance Lease, Weighted Average Remaining Lease Term 11 years 12 years
Operating Lease, Weighted Average Discount Rate, Percent 1.50% 1.50%
Finance Lease, Weighted Average Discount Rate, Percent 17.80% 17.70%
v3.22.2.2
Leases, Future Minimum Payments (Details)
$ in Millions
Sep. 30, 2022
USD ($)
Lessee, Lease, Description [Line Items]  
Operating Leases, Future Minimum Payments Due, Next Twelve Months $ 61
Operating Leases, Future Minimum Payments, Due in Two Years 43
Operating Leases, Future Minimum Payments, Due in Three Years 35
Operating Leases, Future Minimum Payments, Due in Four Years 10
Operating Leases, Future Minimum Payments, Due in Five Years 2
Operating Leases, Future Minimum Payments, Due Thereafter 5
Total 156
Present value of future minimum lease payments, operating (4)
Operating present value of net minimum lease payments 152
Finance Lease, Liability, to be Paid, Year One 112
Finance Lease, Liability, to be Paid, Year Two 107
Finance Lease, Liability, to be Paid, Year Three 106
Finance Lease, Liability, to be Paid, Year Four 105
Finance Lease, Liability, to be Paid, Year Five 104
Finance Lease, Liability, Payments Due Thereafter 552
Finance Lease, Liability, Payment, Due 1,086
Finance Lease, Liability, Payment Amounts Representing Interest (399)
Finance Lease, Liability 687
Purchased Power Lease 414
Purchased Power Lease - Gulch Union $ 15
v3.22.2.2
Deferred Costs, Capitalized, Prepaid, and Other Assets (Details) - USD ($)
$ in Millions
Sep. 30, 2022
Sep. 30, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]    
Other Assets, Miscellaneous, Current $ 85 $ 77