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Debt and Other Obligations Debt and Other Obligations - Debt Outstanding (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2016 | Jan. 17, 2012
Debt Instrument |  |  |  |  |  |
Debt Securities |  |  |  | $ 1,000 |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  |  |  | 7.10%
Short-term debt, net of discounts |  | $ 1,998 |  | 1,216 | $ 1,407 |
Current maturities of long-term debt of variable interest entities issued at par |  | 36 |  | 38 |  |
Current maturities of notes payable |  | 53 |  | 46 |  |
Total Current maturities of power bonds issued at par |  | 1,728 |  | 1,032 |  |
Current maturities of power bonds |  | 1,728 |  | 1,032 |  |
Total current debt outstanding, net |  | 3,815 |  | 2,332 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 20,205 |  | 20,157 |  |
Long-term power bonds | [1] | 20,357 |  | 20,300 |  |
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net |  | 152 |  | (143) |  |
Long-term debt of variable interest entities, net |  | 1,164 |  | 1,127 |  |
Long-term notes payable |  | 69 |  | 23 |  |
Total long-term debt, net |  | 21,438 |  | 21,307 |  |
Foreign Currency Transaction Gain (Loss), before Tax |  | 125 |  | $ 147 |  |
880591EV0 [Member] |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 2.25% |  |
Debt Instrument, Maturity Date |  |  |  | Mar. 15, 2020 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 0 |  | $ 1,000 |  |
880591DX7 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate | [2] |  |  | 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 |  | 303 |  | $ 273 |  |
880591DC3 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 5.805% |  |
Debt Instrument, Maturity Date |  |  |  | Jun. 07, 2021 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 268 |  | $ 261 |  |
880591EL2 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 3.875% |  |
Debt Instrument, Maturity Date |  |  |  | Feb. 15, 2021 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 1,500 |  | $ 1,500 |  |
880591EQ1 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 1.75% |  |
Debt Instrument, Maturity Date |  |  |  | Oct. 15, 2018 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 1,000 |  | $ 0 |  |
electronotes |  |  |  |  |  |
Long-term debt |  |  |  |  |  |
Maturity date - earliest |  |  |  | May 15, 2020 |  |
Maturity date - latest |  |  |  | Feb. 15, 2043 |  |
Call date - earliest |  |  |  | Feb. 15, 2015 |  |
Call date - latest |  |  |  | Feb. 15, 2018 |  |
Long-term power bonds, net |  | 226 |  | $ 221 |  |
880591EN8 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 1.875% |  |
Debt Instrument, Maturity Date |  |  |  | Aug. 15, 2022 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 1,000 |  | $ 1,000 |  |
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 |  |  |  | 3.55% |  |
Debt Instrument, Maturity Date |  |  |  | Jun. 01, 2028 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 273 |  | $ 273 |  |
880591409 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 3.36% |  |
Debt Instrument, Maturity Date |  |  |  | May 01, 2029 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 232 |  | $ 232 |  |
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 | [3] | $ 472 |  |
880591DP4 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 6.587% |  |
Debt Instrument, Maturity Date |  |  |  | Jun. 07, 2032 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 335 | [3] | $ 326 |  |
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 | [4] | $ 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 |  | 201 |  | $ 195 |  |
880591CF7 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 6.235% |  |
Debt Instrument, Maturity Date |  |  |  | Jul. 15, 2045 |  |
Long-term debt |  |  |  |  |  |
Long-term power bonds, net |  | 140 |  | $ 140 |  |
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 | [2] |  |  | 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 |  |
880591EQ1 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 1.75% |  |
Total Current maturities of power bonds issued at par |  | 0 |  | $ 1,000 |  |
Debt Instrument, Maturity Date |  |  |  | Oct. 15, 2018 |  |
880591EF5 (6/15/2018) |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Total Current maturities of power bonds issued at par |  | 28 |  | $ 29 |  |
Debt Instrument, Maturity Date |  |  |  | Jun. 15, 2019 |  |
88059TFS5 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 4.125% |  |
Debt Instrument, Maturity Date |  |  |  | Oct. 15, 2017 |  |
Bonds outstanding with survivor's option |  | 46 |  | $ 0 |  |
880591EF5 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 3.77% |  |
Total Current maturities of power bonds issued at par |  | 1 |  | $ 1 |  |
Debt Instrument, Maturity Date |  |  |  | Dec. 15, 2018 |  |
88059TEL1 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 2.65% |  |
Total Current maturities of power bonds issued at par |  | 1 |  | $ 1 |  |
Debt Instrument, Maturity Date |  |  |  | Nov. 15, 2018 |  |
88059TEL1 (5/15/2018) |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Total Current maturities of power bonds issued at par |  | 2 |  | $ 1 |  |
Debt Instrument, Maturity Date |  |  |  | May 15, 2019 |  |
880591DS8 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Total Current maturities of power bonds issued at par |  | 650 |  | $ 0 |  |
Debt Instrument, Maturity Date |  |  |  | Dec. 15, 2017 |  |
880591EA6 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Total Current maturities of power bonds issued at par |  | $ 1,000 |  | $ 0 |  |
Debt Instrument, Maturity Date |  |  |  | Apr. 01, 2018 |  |
880591EC2 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 4.50% |  |
880591CU4 |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 6.25% |  |
Minimum | electronotes |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 2.375% |  |
Maximum | electronotes |  |  |  |  |  |
Short-term debt |  |  |  |  |  |
Coupon rate |  |  |  | 3.625% |  |
[1] | Includes net exchange gain from currency transactions of $147 million and $125 million at September 30, 2018 and
[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 and Call Options above.
[4] | (2) Includes one electronotes® issue with partial maturities of principal for each required annual payment.

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