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Unaudited Financial Information (Table) | 6 Months Ended
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Mar. 31, 2018
Regulatory Assets And Liabilities Table [Abstract] |
Schedule Of Regulatory Assets And Liabilities [Table Text Block] | Significant regulatory assets and liabilities as of March 31, 2018 and September 30, 2017 included the following:
| March 31, 2018 |  | September 30, 2017
| (In thousands)
Regulatory assets: |  |  |
Pension and postretirement benefit costs(1) | $ | 20,918 |  |  | $ | 26,826 |
Infrastructure mechanisms(2) | 65,286 |  |  | 46,437 |
Deferred gas costs | — |  |  | 65,714 |
Recoverable loss on reacquired debt | 9,954 |  |  | 11,208 |
Deferred pipeline record collection costs | 14,646 |  |  | 11,692 |
APT annual adjustment mechanism | — |  |  | 2,160 |
Rate case costs | 3,016 |  |  | 2,629 |
Other | 8,064 |  |  | 10,132 |
| $ | 121,884 |  |  | $ | 176,798 |
Regulatory liabilities: |  |  |
Regulatory excess deferred taxes(3) | $ | 737,798 |  |  | $ | — |
Regulatory cost of service reserve(4) | 29,042 |  |  | — |
Regulatory cost of removal obligation | 526,483 |  |  | 521,330 |
Deferred gas costs | 167,036 |  |  | 15,559 |
Asset retirement obligation | 12,827 |  |  | 12,827 |
APT annual adjustment mechanism | 5,081 |  |  | — |
Other | 14,740 |  |  | 5,941 |
| $ | 1,493,007 |  |  | $ | 555,657 |
(1) | Includes $7.8 million and $9.4 million of pension and postretirement expense deferred pursuant to regulatory authorization.
(2) | Infrastructure mechanisms in Texas and Louisiana allow for the deferral of all eligible expenses associated with capital expenditures incurred pursuant to these rules, including the recording of interest on deferred expenses until the next rate proceeding (rate case or annual rate filing), at which time investment and costs would be recoverable through base rates.
(3) | The TCJA resulted in the remeasurement of the net deferred tax liability included in our rate base. The excess deferred taxes will be returned to utility customers in accordance with regulatory requirements. See Note 6 for further information.
(4) | Effective January 1, 2018, regulators in each of our service areas required us to establish a regulatory liability for the difference in recoverable federal taxes included in revenues based on the former 35% federal statutory rate and the new 21% federal statutory rate for service provided on or after January 1, 2018. This liability will be returned to utility customers in accordance with regulatory requirements. See Note 6 for further information.

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- Definition Tabular disclosure of regulatory assets and liabilities, including current and noncurrent assets created when regulatory agencies permit the deferral of costs to the balance sheet that would otherwise be required to appear on the company's income statement and would be charged against current expenses or revenues, as well as current and noncurrent liabilities that result from rate actions of a regulator. + References No definition available. + Details
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