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Benefit Plans Benefit Plans (Tables) | 12 Months Ended
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Sep. 30, 2019
Retirement Benefits [Abstract] |
Obligations and Funded Status | The changes in plan obligations, assets, and funded status for the years ended September 30, 2019 and 2018, were as follows:
Obligations and Funded Status For the years ended September 30
798,000,000 |  | Pension Benefits |  | Other Post-Retirement Benefits
| 2019 |  | 2018 |  | 2019 |  | 2018
Change in benefit obligation |  |  |  |  |  |  |
Benefit obligation at beginning of year | $ | 11,725 |  |  | $ | 12,601 |  |  | $ | 428 |  |  | $ | 494 |
Service cost | 44 |  |  | 53 |  |  | 11 |  |  | 14 |
Interest cost | 499 |  |  | 473 |  |  | 18 |  |  | 19 |
Plan participants' contributions | 7 |  |  | 7 |  |  | — |  |  | — |
Collections(1) | — |  |  | — |  |  | 22 |  |  | 25 |
Actuarial (gain) loss | 1,756 |  |  | (658 | ) |  | 78 |  |  | (46 | )
Plan change | 7 |  |  | — |  |  | — |  |  | (17 | )
Net transfers (to) from variable fund/401(k) plan(2) | 1 |  |  | (26 | ) |  | — |  |  | — |
Expenses paid | (6 | ) |  | (6 | ) |  | — |  |  | — |
Benefits paid | (721 | ) |  | (719 | ) |  | (58 | ) |  | (61 | )
Benefit obligation at end of year | 13,312 |  |  | 11,725 |  |  | 499 |  |  | 428 |
Change in plan assets |  |  |  |  |  |  |  |  |  |  |
Fair value of net plan assets at beginning of year | 8,003 |  |  | 7,989 |  |  | — |  |  | — |
Actual return on plan assets | 389 |  |  | 454 |  |  | — |  |  | — |
Plan participants' contributions | 7 |  |  | 7 |  |  | — |  |  | — |
Collections(1) | — |  |  | — |  |  | 22 |  |  | 25 |
Net transfers (to) from variable fund/401(k) plan(2) | 1 |  |  | (26 | ) |  | — |  |  | — |
Employer contributions | 307 |  |  | 304 |  |  | 36 |  |  | 36 |
Expenses paid | (6 | ) |  | (6 | ) |  | — |  |  | — |
Benefits paid | (721 | ) |  | (719 | ) |  | (58 | ) |  | (61 | )
Fair value of net plan assets at end of year | 7,980 |  |  | 8,003 |  |  | — |  |  | — |
Funded status | $ | (5,332 | ) |  | $ | (3,722 | ) |  | $ | (499 | ) |  | $ | (428 | )
Notes (1) Collections include retiree contributions as well as provider discounts and rebates. (2) Includes one-time transfers to the 401(k) of $23 million related to the 2018 plan amendment.
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, 2019 and 2018, 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
| Pension Benefits |  | Other Post-Retirement Benefits
| 2019 |  | 2018 |  | 2019 |  | 2018
Regulatory assets (liabilities) | $ | 4,731 |  |  | $ | 3,119 |  |  | $ | 25 |  |  | $ | (73 | )
Accounts payable and accrued liabilities | (5 | ) |  | (6 | ) |  | (28 | ) |  | (28 | )
Pension and post-retirement benefit obligations(1) | (5,327 | ) |  | (3,716 | ) |  | (471 | ) |  | (400 | )
Note (1) The table above excludes $383 million and $360 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, 2019 and 2018, 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, 2019 and 2018, consisted of the following:
Post-Retirement Benefit Costs Deferred as Regulatory Assets (Liabilities) At September 30
| Pension Benefits |  | Other Post-Retirement Benefits
| 2019 |  | 2018 |  | 2019 |  | 2018
Unrecognized prior service credit | $ | (714 | ) |  | $ | (819 | ) |  | $ | (135 | ) |  | $ | (159 | )
Unrecognized net loss | 5,350 |  |  | 3,842 |  |  | 160 |  |  | 86 |
Amount capitalized due to actions of regulator | 95 |  |  | 96 |  |  | — |  |  | — |
Total regulatory assets (liabilities) | $ | 4,731 |  |  | $ | 3,119 |  |  | $ | 25 |  |  | $ | (73 | )
Projected Benefit Obligations and Accumulated Benefit Obligations in Excess of Plan Assets | The projected benefit obligation, accumulated benefit obligation, and fair value of plan assets for the pension plan at September 30, 2019 and 2018, were as follows:
Projected Benefit Obligations and Accumulated Benefit Obligations in Excess of Plan Assets At September 30
| 2019 |  | 2018
Projected benefit obligation | $ | 13,312 |  |  | $ | 11,725 |
Accumulated benefit obligation | 13,246 |  |  | 11,659 |
Fair value of net plan assets | 7,980 |  |  | 8,003 |
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, 2019, 2018, and 2017 were as follows:
Components of Net Periodic Benefit Cost For the years ended September 30
| Pension Benefits |  | Other Post-Retirement Benefits
| 2019 |  | 2018 |  | 2017 |  | 2019 |  | 2018 |  | 2017
Service cost | $ | 44 |  |  | $ | 53 |  |  | $ | 60 |  |  | $ | 11 |  |  | $ | 14 |  |  | $ | 18 |
Interest cost | 499 |  |  | 473 |  |  | 464 |  |  | 18 |  |  | 19 |  |  | 21 |
Expected return on plan assets | (477 | ) |  | (478 | ) |  | (457 | ) |  | — |  |  | — |  |  | — |
Amortization of prior service credit | (99 | ) |  | (99 | ) |  | (99 | ) |  | (24 | ) |  | (22 | ) |  | (22 | )
Recognized net actuarial loss | 336 |  |  | 409 |  |  | 472 |  |  | 4 |  |  | 8 |  |  | 14 |
Total net periodic benefit cost as actuarially determined | 303 |  |  | 358 |  |  | 440 |  |  | 9 |  |  | 19 |  |  | 31 |
Amount expensed (capitalized) due to actions of regulator | 1 |  |  | (54 | ) |  | 365 |  |  | — |  |  | — |  |  | — |
Net periodic benefit cost | $ | 304 |  |  | $ | 304 |  |  | $ | 805 |  |  | $ | 9 |  |  | $ | 19 |  |  | $ | 31 |
Expected Amortization of Regulatory Assets in Next Fiscal Year | The amounts in the regulatory asset that are expected to be recognized as components of net periodic benefit cost during the next fiscal year are as follows:
Expected Amortization of Regulatory Assets in 2020 At September 30, 2019
| Pension Benefits |  | Other Post-Retirement Benefits |  | Total
Prior service credit | $ | (97 | ) |  | $ | (24 | ) |  | $ | (121 | )
Net actuarial loss | 435 |  |  | 9 |  |  | 444 |
Actuarial Assumptions | TVA's reported costs of providing the plan benefits are impacted by numerous factors including the provisions of the plans, changing employee demographics, and various assumptions, the most significant of which are noted below.
Actuarial Assumptions Utilized to Determine Benefit Obligations at September 30
| Pension Benefits |  | Other Post-Retirement Benefits
| 2019 |  | 2018 |  | 2019 |  | 2018
Discount rate | 3.20 | % |  | 4.35 | % |  | 3.30 | % |  | 4.40 | %
Rate of compensation increase | 3.50 | % |  | 3.60 | % |  | N/A |  |  | N/A |
Cost of living adjustment (COLA)(1) | 2.00 | % |  | 2.00 | % |  | 2.00 | % |  | 2.00 | %
Pre-Medicare eligible |  |  |  |  |  |  |
Initial health care cost trend rate | N/A |  |  | N/A |  |  | 6.75 | % |  | 6.25 | %
Ultimate health care cost trend rate | N/A |  |  | N/A |  |  | 5.00 | % |  | 5.00 | %
Year ultimate trend rate is reached | N/A |  |  | N/A |  |  | 2027 |  |  | 2024 |
Post-Medicare eligible |  |  |  |  |  |  |
Initial health care cost trend rate | N/A |  |  | N/A |  |  | — | % |  | — | %
Ultimate health care cost trend rate | N/A |  |  | N/A |  |  | 4.00 | % |  | 4.00 | %
Year ultimate trend rate is reached | N/A |  |  | N/A |  |  | 2023 |  |  | 2021 |
Note (1) The COLA rate is the ultimate long-term rate.
Actuarial Assumptions Utilized to Determine Net Periodic Benefit Cost for the Years Ended September 30(1)
| Pension Benefits |  | Other Post-Retirement Benefits
| 2019 |  | 2018 |  | 2017 |  | 2019 |  | 2018 |  | 2017
Discount rate | 4.35 | % |  | 3.85 | % |  | 3.65 | % |  | 4.40 | % |  | 3.95 | % |  | 3.70 | %
Expected return on plan assets | 6.75 | % |  | 6.75 | % |  | 7.00 | % |  | N/A |  |  | N/A |  |  | N/A |
Cost of living adjustment (COLA)(2) | 2.00 | % |  | 2.00 | % |  | 2.00 | % |  | 2.00 | % |  | 2.00 | % |  | 2.00 | %
Rate of compensation increase | 3.50 | % |  | 5.34 | % |  | 5.43 | % |  | N/A |  |  | N/A |  |  | N/A |
Pre-Medicare eligible |  |  |  |  |  |  |  |  |  |  |
Initial health care cost trend rate | N/A |  |  | N/A |  |  | N/A |  |  | 6.25 | % |  | 6.50 | % |  | 6.50 | %
Ultimate health care cost trend rate | N/A |  |  | N/A |  |  | N/A |  |  | 5.00 | % |  | 5.00 | % |  | 5.00 | %
Year ultimate trend rate is reached | N/A |  |  | N/A |  |  | N/A |  |  | 2024 |  |  | 2024 |  |  | 2019 |
Post-Medicare eligible |  |  |  |  |  |  |  |  |  |  |
Initial health care cost trend rate | N/A |  |  | N/A |  |  | N/A |  |  | — | % |  | — | % |  | — | %
Ultimate health care cost trend rate | N/A |  |  | N/A |  |  | N/A |  |  | 4.00 | % |  | 4.00 | % |  | 4.00 | %
Year ultimate trend rate is reached | N/A |  |  | N/A |  |  | N/A |  |  | 2021 |  |  | 2021 |  |  | 2021 |
Notes (1) The actuarial assumptions used to determine the benefit obligations at September 30 of each year are subsequently used to determine net periodic benefit cost for the following year
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 At September 30, 2019
Actuarial Assumption |  | Change in Assumption |  | Impact on 2019 Pension Cost |  | Impact on 2019 Projected Benefit Obligation
Discount rate |  | (0.25 | )% |  | $ | 16 |  |  | $ | 399 |
Rate of return on plan assets |  | (0.25 | )% |  | 14 |  |  | N/A |
Cost of living adjustments |  | 0.25 | % |  | 27 |  |  | 261 |
Sensitivity to Changes in Assumed Health Care Cost Trend Rates | The following chart reflects the sensitivity of post-retirement benefit cost to changes in the health care trend rate:
Sensitivity to Changes in Assumed Health Care Cost Trend Rates At September 30, 2019
| 1% Increase |  | 1% Decrease
Effect on total of service and interest cost components for the year | $ | 4 |  |  | $ | (4 | )
Effect on end-of-year accumulated post-retirement benefit obligation | 71 |  |  | (68 | )
Asset Holdings and Fair Value Measurements | s consistent with the asset allocation policy. At September 30, 2019 and 2018, the asset holdings of TVARS included the following:
Asset Holdings of TVARS At September 30
|  |  |  | Plan Assets at September 30
Asset Category |  | Target Allocation |  | 2019 |  | 2018
Global public equity |  | 35 | % |  | 37 | % |  | 44 | %
Private equity |  | 8 | % |  | 10 | % |  | 7 | %
Safety oriented fixed income |  | 17 | % |  | 18 | % |  | 16 | %
Opportunistic fixed income |  | 15 | % |  | 12 | % |  | 10 | %
Public real assets |  | 15 | % |  | 15 | % |  | 15 | %
Private real assets |  | 10 | % |  | 8 | % |  | 8 | %
Total |  | 100 | % |  | 100 | % |  | 100 | %
Fair Value Measurements The following table provides the fair value measurement amounts for assets held by TVARS at September 30, 2019:
TVA Retirement System At September 30, 2019
| 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 | $ | 1,766 |  |  | $ | 1,762 |  |  | $ | — |  |  | $ | 4 |
Preferred securities | 10 |  |  | 1 |  |  | 9 |  |  | — |
Debt securities |  |  |  |  |  |  |  |  |  |
Corporate debt securities | 1,387 |  |  | — |  |  | 1,382 |  |  | 5 |
Residential mortgage-backed securities | 427 |  |  | — |  |  | 424 |  |  | 3 |
Debt securities issued by U.S. Treasury | 807 |  |  | 807 |  |  | — |  |  | — |
Debt securities issued by foreign governments | 210 |  |  | — |  |  | 209 |  |  | 1 |
Asset-backed securities | 144 |  |  | — |  |  | 116 |  |  | 28 |
Debt securities issued by state/local governments | 18 |  |  | — |  |  | 18 |  |  | — |
Commercial mortgage-backed securities | 81 |  |  | — |  |  | 80 |  |  | 1 |
Commingled funds measured at net asset value(3) |  |  |  |  |  |  |  |
Equity | 795 |  |  | — |  |  | — |  |  | — |
Debt | 308 |  |  | — |  |  | — |  |  | — |
Commodities | 217 |  |  | — |  |  | — |  |  | — |
Blended | 125 |  |  | — |  |  | — |  |  | — |
Institutional mutual funds | 97 |  |  | 97 |  |  | — |  |  | — |
Cash equivalents and other short-term investments | 329 |  |  | 1 |  |  | 328 |  |  | — |
Certificates of deposit | 3 |  |  | — |  |  | 3 |  |  | — |
Private credit measured at net asset value(3) | 78 |  |  | — |  |  | — |  |  | — |
Private equity measured at net asset value(3) | 891 |  |  | — |  |  | — |  |  | — |
Private real estate measured at net asset value(3) | 546 |  |  | — |  |  | — |  |  | — |
Securities lending collateral | 224 |  |  | — |  |  | 224 |  |  | — |
Derivatives |  |  |  |  |  |  |  |  |  |  |
Futures | 2 |  |  | 2 |  |  | — |  |  | — |
Swaps | 5 |  |  | — |  |  | 5 |  |  | — |
Options | 1 |  |  | — |  |  | 1 |  |  | — |
Foreign currency forward receivable | 1 |  |  | — |  |  | 1 |  |  | — |
Total assets | $ | 8,472 |  |  | $ | 2,670 |  |  | $ | 2,800 |  |  | $ | 42 |
Liabilities |  |  |  |  |  |  |  |  |  |  |
Derivatives |  |  |  |  |  |  |
Futures | $ | 4 |  |  | $ | 4 |  |  | $ | — |  |  | $ | — |
Foreign currency forward payable | 1 |  |  | — |  |  | 1 |  |  | — |
Swaps | 12 |  |  | — |  |  | 12 |  |  | — |
Options | 1 |  |  | — |  |  | 1 |  |  | — |
Securities sold under agreements to repurchase | 118 |  |  | — |  |  | 118 |  |  | — |
Total liabilities | $ | 136 |  |  | $ | 4 |  |  | $ | 132 |  |  | $ | — |
Notes (1) Excludes approximately $132 million in net payables associated with security purchases and sales and various other payables. (2) Excludes a $224 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 net asset value 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, 2018:
TVA Retirement System At September 30, 2018
| 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 | $ | 1,787 |  |  | $ | 1,786 |  |  | $ | — |  |  | $ | 1 |
Preferred securities | 10 |  |  | 4 |  |  | 6 |  |  | — |
Debt securities |  |  |  |  |  |  |  |  |  |
Corporate debt securities | 1,151 |  |  | — |  |  | 1,148 |  |  | 3 |
Residential mortgage-backed securities | 377 |  |  | — |  |  | 371 |  |  | 6 |
Debt securities issued by U.S. Treasury | 696 |  |  | 696 |  |  | — |  |  | — |
Debt securities issued by foreign governments | 322 |  |  | — |  |  | 304 |  |  | 18 |
Asset-backed securities | 129 |  |  | — |  |  | 103 |  |  | 26 |
Debt securities issued by state/local governments | 17 |  |  | — |  |  | 17 |  |  | — |
Commercial mortgage-backed securities | 74 |  |  | — |  |  | 70 |  |  | 4 |
Commingled funds measured at net asset value(3) |  |  |  |  |  |  |  |
Equity | 1,175 |  |  | — |  |  | — |  |  | — |
Debt | 317 |  |  | — |  |  | — |  |  | — |
Commodities | 232 |  |  | — |  |  | — |  |  | — |
Blended | 109 |  |  | — |  |  | — |  |  | — |
Institutional mutual funds | 109 |  |  | 109 |  |  | — |  |  | — |
Cash equivalents and other short-term investments | 466 |  |  | 42 |  |  | 424 |  |  | — |
Certificates of deposit | 2 |  |  | — |  |  | 2 |  |  | — |
Private credit measured at net asset value(3) | 8 |  |  | — |  |  | — |  |  | — |
Private equity measured at net asset value(3) | 631 |  |  | — |  |  | — |  |  | — |
Private real estate measured at net asset value(3) | 583 |  |  | — |  |  | — |  |  | — |
Securities lending collateral | 318 |  |  | — |  |  | 318 |  |  | — |
Derivatives |  |  |  |  |  |  |
Futures | 7 |  |  | 7 |  |  | — |  |  | — |
Swaps | 8 |  |  | — |  |  | 8 |  |  | — |
Foreign currency forward receivable | 3 |  |  | — |  |  | 3 |  |  | — |
Total assets | $ | 8,531 |  |  | $ | 2,644 |  |  | $ | 2,774 |  |  | $ | 58 |
Liabilities |  |  |  |  |  |  |  |  |  |  |
Derivatives |  |  |  |  |  |  |
Futures | $ | 3 |  |  | $ | 3 |  |  | $ | — |  |  | $ | — |
Foreign currency forward payable | 3 |  |  | — |  |  | 3 |  |  | — |
Options | 1 |  |  | — |  |  | 1 |  |  | — |
Securities sold under agreements to repurchase | 108 |  |  | — |  |  | 108 |  |  | — |
Total liabilities | $ | 115 |  |  | $ | 3 |  |  | $ | 112 |  |  | $ | — |
Notes (1) Excludes approximately $95 million in net payables associated with security purchases and sales and various other payables. (2) Excludes a $318 million payable for collateral on loaned securities in connection with TVARS's participation in securities lending programs.
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
| Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
Balance at October 1, 2017 | $ | 88 |
Net realized/unrealized gains (losses) | (4 | )
Purchases, sales, issuances, and settlements (net) | (23 | )
Transfers in and/or out of Level 3 | (3 | )
Balance at September 30, 2018 | 58 |
Net realized/unrealized gains (losses) | 4 |
Purchases, sales, issuances, and settlements (net) | (12 | )
Transfers in and/or out of Level 3 | (8 | )
Balance at September 30, 2019 | $ | 42 |
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, 2019
| Pension Benefits(1) |  | Other Post-Retirement Benefits
2020 | $ | 782 |  |  | $ | 29 |
2021 | 779 |  |  | 27 |
2022 | 778 |  |  | 25 |
2023 | 775 |  |  | 24 |
2024 | 771 |  |  | 22 |
2025 - 2029 | 3,786 |  |  | 111 |
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 related to other post-employment benefit obligations are recognized on TVA's Consolidated Balance Sheets. The current portion which represents unpaid losses and administrative fees due are in Accounts payable and accrued liabilities. The long-term portion is recognized in Post-retirement and post-employment benefit obligations.
Amounts Recognized on TVA's Consolidated Balance Sheets At September 30
| 2019 |  | 2018
Accounts payable and accrued liabilities | $ | 36 |  |  | $ | 39 |
Post-retirement and post-employment benefit obligations | 383 |  |  | 360 |

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