Revenue from Contracts with Customers (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023 |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | $ 338,644 | $ 369,791 | $ 1,397,392 | $ 1,917,917 |
Alternative Revenue Programs | 3,336 | 1,071 | 19,949 | 6,995 |
Derivative Financial Instruments | 75,462 | 57,842 | 155,401 | (120,088) |
Total Revenues | 417,442 | 428,704 | 1,572,742 | 1,804,824 |
All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Alternative Revenue Programs | 0 | 0 | 0 | 0 |
Derivative Financial Instruments | 0 | 0 | 0 | 0 |
Total Revenues | 0 | 0 | 0 | 0 |
Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | (93,946) | (83,795) | (278,804) | (254,151) |
Alternative Revenue Programs | 0 | 0 | 0 | 0 |
Derivative Financial Instruments | 0 | 0 | 0 | 0 |
Total Revenues | (93,946) | (83,795) | (278,804) | (254,151) |
Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 145,443 | 158,739 | 584,136 | 858,195 |
Alternative Revenue Programs | 0 | 0 | 0 | 0 |
Derivative Financial Instruments | 75,462 | 57,842 | 155,401 | (120,088) |
Total Revenues | 220,905 | 216,581 | 739,537 | 738,107 |
Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 105,419 | 92,395 | 307,852 | 285,154 |
Alternative Revenue Programs | 0 | 0 | 0 | 0 |
Derivative Financial Instruments | 0 | 0 | 0 | 0 |
Total Revenues | 105,419 | 92,395 | 307,852 | 285,154 |
Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 60,120 | 58,906 | 186,701 | 172,300 |
Alternative Revenue Programs | 0 | 0 | 0 | 0 |
Derivative Financial Instruments | 0 | 0 | 0 | 0 |
Total Revenues | 60,120 | 58,906 | 186,701 | 172,300 |
Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 121,608 | 143,546 | 597,507 | 856,419 |
Alternative Revenue Programs | 3,336 | 1,071 | 19,949 | 6,995 |
Derivative Financial Instruments | 0 | 0 | 0 | 0 |
Total Revenues | 124,944 | 144,617 | 617,456 | 863,414 |
Production of Natural Gas | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 144,374 | 157,682 | 580,233 | 849,811 |
Production of Natural Gas | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 144,374 | 157,682 | 580,233 | 849,811 |
Production of Natural Gas | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 511 | 483 | 1,722 | 1,637 |
Production of Crude Oil | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 511 | 483 | 1,722 | 1,637 |
Production of Crude Oil | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 195 | 284 | 765 | 867 |
Natural Gas Processing | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 195 | 284 | 765 | 867 |
Natural Gas Processing | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 3,644 | 4,629 | 12,157 | 9,003 |
Natural Gas Gathering Service | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | (56,476) | (54,277) | (174,544) | (163,297) |
Natural Gas Gathering Service | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 60,120 | 58,906 | 186,701 | 172,300 |
Natural Gas Gathering Service | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Transportation Service | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 74,504 | 70,018 | 248,309 | 241,619 |
Natural Gas Transportation Service | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Transportation Service | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | (26,826) | (20,311) | (73,040) | (62,880) |
Natural Gas Transportation Service | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Transportation Service | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 79,640 | 70,424 | 232,532 | 220,420 |
Natural Gas Transportation Service | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Transportation Service | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 21,690 | 19,905 | 88,817 | 84,079 |
Natural Gas Storage Service | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 14,176 | 12,141 | 40,727 | 36,682 |
Natural Gas Storage Service | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Storage Service | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | (10,436) | (9,006) | (30,520) | (27,221) |
Natural Gas Storage Service | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Storage Service | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 24,612 | 21,147 | 71,247 | 63,903 |
Natural Gas Storage Service | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Storage Service | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 89,034 | 108,398 | 445,971 | 671,352 |
Natural Gas Residential Sales | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 89,034 | 108,398 | 445,971 | 671,352 |
Natural Gas Commercial Sales | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 11,022 | 13,971 | 62,117 | 97,432 |
Natural Gas Commercial Sales | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 11,022 | 13,971 | 62,117 | 97,432 |
Natural Gas Industrial Sales | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 479 | 864 | 2,663 | 5,267 |
Natural Gas Industrial Sales | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | (1) | (2) | (5) | (6) |
Natural Gas Industrial Sales | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 480 | 866 | 2,668 | 5,273 |
Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 705 | 1,321 | 2,728 | 4,247 |
Other | All Other | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Other | Corporate and Intersegment Eliminations | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | (207) | (199) | (695) | (747) |
Other | Exploration and Production | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 363 | 290 | 1,416 | 5,880 |
Other | Pipeline and Storage | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 1,167 | 824 | 4,073 | 831 |
Other | Gathering | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | 0 | 0 | 0 | 0 |
Other | Utility | Total Reportable Segments | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Total Revenues from Contracts with Customers | $ (618) | $ 406 | $ (2,066) | $ (1,717) |