Risk Management Activities and Derivative Transactions Collateral (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Derivative
Amount of letters of credit outstanding	$ 6
Forward Contract Derivative Asset, at Fair Value	3	$ 11
Likely cash collateral obligation increase	22
Derivative Liability, Subject to Master Netting Arrangement, after Offset	1,250	991
Collateralized Securities [Member]
Derivative
Derivative, Collateral, Right to Reclaim Cash	537
Credit Risk
Derivative
Derivative Liability, Subject to Master Netting Arrangement, after Offset	1,300
Letter of Credit
Derivative
Amount of letters of credit outstanding	469	535
Interest Swap Collateral
Derivative
Amount of letters of credit outstanding	443
Interest rate swap collateral
Derivative
Amount of letters of credit outstanding		509
Fair Value, Inputs, Level 2
Derivative
Forward Contract Derivative Asset, at Fair Value	$ 3	$ 11

Fair value as of the balance sheet date of forward contract derivative assets.

No definition available.

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- Definition

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

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- Definition

Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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- Definition

Fair value, after effect of master netting arrangement, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and contract can be net settled by means outside contract or delivery of asset. Includes derivative subject to master netting arrangement not elected or qualified to offset. Excludes derivative not subject to master netting arrangement or similar agreement.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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- Details

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- Details

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