Other Long-Term Liabilities Other Long-Term Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2017		Sep. 30, 2016
Other Long-Term Liabilities
Interest rate swap liabilities	$ 1,511		$ 1,938
Capital lease obligations	302		409
Currency swap liabilities	103	[1]	162	[2]
EnergyRight financing obligation	161		183
Non-current regulatory liabilities	25		3
Total other long-term liabilities	3,055		2,773
Other long-term liabilities
Other Long-Term Liabilities
Interest rate swap liabilities	1,418		1,938
Gallatin coal combustion residual facilities	880		0
Capital lease obligations	182		177
Currency swap liabilities	92		162
EnergyRight financing obligation	115		130
Environmental agreements liability	13		18
Membership interests of VIE subject to mandatory redemption	30		33
Commodity contract derivative liabilities	9		49
Other	316		266
Accounts payable and accrued liabilities
Other Long-Term Liabilities
Gallatin coal combustion residual facilities	19
EnergyRight financing obligation	$ 29		$ 33

[1] Due to the right of setoff and method of settlement, TVA elects to record commodity derivatives under the FTP based on its net commodity position with the counterparty or FCM. Deposits are made to TVA's margin cash accounts held with each FCM to offset any net liability positions in full for derivatives that are transacted with FCMs. 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 — Offsetting of Derivative Assets and Liabilities.

[2] Due to the right of setoff and method of settlement, TVA elects to record commodity derivatives under the FTP based on its net commodity position with the counterparty or FCM. Deposits are made to TVA's margin cash accounts held with each FCM to offset any net liability positions in full for derivatives that are transacted with FCMs. TVA records currency swaps net of any 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 — Offsetting of Derivative Assets and Liabilities.