Risk Management Activities and Derivative Transactions Counterparty Credit Risk (Details) $ in Millions	3 Months Ended
Dec. 31, 2023 USD ($) Customers	Sep. 30, 2023 USD ($)
Derivative
Accounts Receivable, before Allowance for Credit Loss, Current \| $	$ 1,451	$ 1,627
Two Largest Customer Percentage of Total Operating Revenue	1600.00%
Moody's, A1 Rating [Member]
Derivative
Natural Gas Banking Counterparties Credit Rating	A1
Moody's, B1 Rating [Member]
Derivative
Natural Gas Banking Counterparties Credit Rating	B1
Moody's, A2 Rating
Derivative
Banking Counterparties Credit Rating	A2
Credit of Customers
Derivative
Number of customers that represent the percent of sales	2
Number of customers that represent the percent of sales	2

Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483467/210-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-9

Name:	us-gaap_AccountsReceivableGrossCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant