Revenue from Contracts with Customers (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021 |
Disaggregation of Revenue [Line Items] | | | | |
Revenue | $ 502,624 | $ 394,397 | $ 1,750,900 | $ 1,386,671 |
Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 551,010 | 222,816 | 1,349,699 | 638,467 |
Alternative Revenue Programs Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Derivative Financial Instruments Outside Scope of Authoritative Guidance on Revenue Recognition | (298,372) | (13,281) | (591,271) | (17,351) |
Revenue | 252,638 | 209,535 | 758,428 | 621,116 |
Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 95,548 | 84,063 | 279,295 | 258,532 |
Alternative Revenue Programs Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Derivative Financial Instruments Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Revenue | 95,548 | 84,063 | 279,295 | 258,532 |
Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 55,931 | 48,656 | 160,759 | 145,927 |
Alternative Revenue Programs Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Derivative Financial Instruments Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Revenue | 55,931 | 48,656 | 160,759 | 145,927 |
Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 178,986 | 123,948 | 778,666 | 576,358 |
Alternative Revenue Programs Outside Scope of Authoritative Guidance on Revenue Recognition | 962 | 3,060 | 7,243 | 10,531 |
Derivative Financial Instruments Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Revenue | 179,948 | 127,008 | 785,909 | 586,889 |
All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 1 | 6 | 1,196 |
Alternative Revenue Programs Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Derivative Financial Instruments Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Revenue | 0 | 1 | 6 | 1,196 |
Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | (81,441) | (74,866) | (233,497) | (226,989) |
Alternative Revenue Programs Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Derivative Financial Instruments Outside Scope of Authoritative Guidance on Revenue Recognition | 0 | 0 | 0 | 0 |
Revenue | (81,441) | (74,866) | (233,497) | (226,989) |
Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 800,034 | 404,618 | 2,334,928 | 1,393,491 |
Alternative Revenue Programs Outside Scope of Authoritative Guidance on Revenue Recognition | 962 | 3,060 | 7,243 | 10,531 |
Derivative Financial Instruments Outside Scope of Authoritative Guidance on Revenue Recognition | (298,372) | (13,281) | (591,271) | (17,351) |
Revenue | 502,624 | 394,397 | 1,750,900 | 1,386,671 |
Production of Natural Gas [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 492,698 | 184,029 | 1,189,940 | 539,241 |
Production of Natural Gas [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Natural Gas [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 492,698 | 184,029 | 1,189,940 | 539,241 |
Production of Crude Oil [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 58,292 | 37,695 | 150,276 | 95,783 |
Production of Crude Oil [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Production of Crude Oil [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 58,292 | 37,695 | 150,276 | 95,783 |
Natural Gas Processing [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 1,016 | 732 | 3,029 | 2,056 |
Natural Gas Processing [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Processing [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 1,016 | 732 | 3,029 | 2,056 |
Natural Gas Gathering Service [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 55,931 | 48,656 | 160,759 | 145,927 |
Natural Gas Gathering Service [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Gathering Service [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | (53,069) | (48,068) | (150,696) | (144,317) |
Natural Gas Gathering Service [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 2,862 | 588 | 10,063 | 1,610 |
Natural Gas Transportation Service [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Transportation Service [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 74,826 | 63,107 | 213,766 | 192,580 |
Natural Gas Transportation Service [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Transportation Service [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 22,019 | 20,201 | 91,276 | 88,736 |
Natural Gas Transportation Service [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Transportation Service [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | (19,173) | (17,786) | (55,031) | (55,562) |
Natural Gas Transportation Service [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 77,672 | 65,522 | 250,011 | 225,754 |
Natural Gas Storage Service [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Storage Service [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 21,084 | 20,646 | 63,334 | 62,394 |
Natural Gas Storage Service [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Storage Service [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Storage Service [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Storage Service [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | (9,024) | (8,926) | (27,302) | (26,797) |
Natural Gas Storage Service [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 12,060 | 11,720 | 36,032 | 35,597 |
Natural Gas Residential Sales [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 138,297 | 93,079 | 604,336 | 434,728 |
Natural Gas Residential Sales [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Residential Sales [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 138,297 | 93,079 | 604,336 | 434,728 |
Natural Gas Commercial Sales [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 17,643 | 10,617 | 84,833 | 56,684 |
Natural Gas Commercial Sales [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Commercial Sales [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 17,643 | 10,617 | 84,833 | 56,684 |
Natural Gas Industrial Sales [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 784 | 488 | 4,124 | 2,778 |
Natural Gas Industrial Sales [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Natural Gas Industrial Sales [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 784 | 488 | 4,124 | 2,778 |
Natural Gas Marketing [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | | 0 | | 0 |
Natural Gas Marketing [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | | 0 | | 0 |
Natural Gas Marketing [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | | 0 | | 0 |
Natural Gas Marketing [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | | 0 | | 0 |
Natural Gas Marketing [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | | 1 | | 651 |
Natural Gas Marketing [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | | (2) | | (22) |
Natural Gas Marketing [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | | (1) | | 629 |
Other [Member] | Exploration And Production [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | (996) | 360 | 6,454 | 1,387 |
Other [Member] | Pipeline And Storage [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | (362) | 310 | 2,195 | 3,558 |
Other [Member] | Gathering [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 0 | 0 |
Other [Member] | Utility [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 243 | (437) | (5,903) | (6,568) |
Other [Member] | All Other [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | 0 | 0 | 6 | 545 |
Other [Member] | Corporate And Intersegment Eliminations [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | (175) | (84) | (468) | (291) |
Other [Member] | Total Consolidated [Member] | | | | |
Disaggregation of Revenue [Line Items] | | | | |
Revenue from Contracts with Customers | $ (1,290) | $ 149 | $ 2,284 | $ (1,369) |