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Other Long-Term Assets (Details) - USD ($) $ in Millions | 6 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Sep. 30, 2017
Other Long-Term Assets |  |
EnergyRight® receivables | $ 119 | $ 127
Currency swap assets, net | 29 |
Other long-term assets | 370 | 323
Other long-term assets |  |
Other Long-Term Assets |  |
Loans and other long-term receivables, net | 142 | 115
EnergyRight® receivables | 95 | 100
Prepaid capacity payments | 31 | 34
Commodity contract derivative assets | 3 | 2
Currency swap assets, net | 29 | 0
Other | 70 | 72
Accounts Receivable |  |
Other Long-Term Assets |  |
EnergyRight® receivables | $ 23 | $ 25
Energy Right |  |
Other Long-Term Assets |  |
Number of days in default | 180 days |
Energy Right | Minimum |  |
Other Long-Term Assets |  |
EnergyRight loan term | 5 years |
Energy Right | Maximum |  |
Other Long-Term Assets |  |
EnergyRight loan term | 10 years |

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