Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation and Environmental Matters In the normal course of business, we are subject to various legal and regulatory proceedings. For such matters, we record liabilities when they are considered probable and estimable, based on currently available facts, our historical experience and our estimates of the ultimate outcome or resolution of the liability in the future. While the outcome of these proceedings is uncertain and a loss in excess of the amount we have accrued is possible though not reasonably estimable, it is the opinion of management that any amounts exceeding the accruals will not have a material adverse impact on our financial position, results of operations or cash flows. We maintain liability insurance for various risks associated with the operation of our natural gas pipelines and facilities, including for property damage and bodily injury. These liability insurance policies generally require us to be responsible for the first $1.0 million (self-insured retention) of each incident. The National Transportation Safety Board (NTSB) is investigating an incident that occurred at a Dallas, Texas residence on February 23, 2018 that resulted in one fatality and injuries to four other residents. Together with the RRC and the PHMSA, Atmos Energy is a party to the investigation and in that capacity is working closely with the NTSB to help determine the cause of this incident. On March 29, 2018, a civil action was filed in Dallas, Texas against Atmos Energy in response to the February 23rd incident. In May 2019, the parties resolved the civil action to their mutual satisfaction subject to our self-insured retention noted above. We are a party to various other litigation and environmental-related matters or claims that have arisen in the ordinary course of our business. While the results of such litigation and response actions to such environmental-related matters or claims cannot be predicted with certainty, we continue to believe the final outcome of such litigation and matters or claims will not have a material adverse effect on our financial condition, results of operations or cash flows. Purchase Commitments Our distribution and pipeline and storage segments maintain supply contracts with several vendors that generally cover a period of up to one year. Commitments for estimated base gas volumes are established under these contracts on a monthly basis at contractually negotiated prices. Commitments for incremental daily purchases are made as necessary during the month in accordance with the terms of the individual contract. Our Mid-Tex Division maintains a limited number of long-term supply contracts to ensure a reliable source of gas for our customers in its service area which obligate it to purchase specified volumes at prices indexed to natural gas trading hubs. At September 30, 2019, we were committed to purchase 40.1 Bcf within one year and 1.6 Bcf within two to three years under indexed contracts. Purchases under these contracts totaled $50.8 million, $57.2 million and $49.7 million for 2019, 2018 and 2017. Rate Regulatory Proceedings Except for routine rate regulatory proceedings as discussed in further detail above in the Business — Ratemaking Activity section, there were no material changes to rate regulatory proceedings during the year ended September 30, 2019. As of September 30, 2019, rate regulatory proceedings were in progress in almost all of our service areas. These regulatory proceedings are discussed in further detail above in the Business — Ratemaking Activity section. Additionally, as discussed in further detail in Note 13, all jurisdictions are addressing impacts of the TCJA.