Borrowings and Other Financing Instruments - Short-Term Borrowings (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Jun. 30, 2025	Dec. 31, 2024
Short-term Debt [Line Items]
Short-term debt	$ 0	$ 85
Money Pool
Short-term Debt [Line Items]
Borrowing limit	250	250
Short-term debt	0	41
Average amount outstanding	68	25
Maximum amount outstanding	$ 250	$ 250
Weighted average interest rate, computed on a daily basis (percentage)	4.33%	5.33%
Short-term Debt, Weighted Average Interest Rate, at Point in Time		4.58%
Commercial Paper
Short-term Debt [Line Items]
Borrowing limit	$ 1,200	$ 700
Short-term debt	0	85
Average amount outstanding	13	71
Maximum amount outstanding	$ 110	$ 492
Weighted average interest rate, computed on a daily basis (percentage)	4.60%	5.55%
Short-term Debt, Weighted Average Interest Rate, at Point in Time		4.58%

The effective interest rate during the reporting period.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
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-Name Accounting Standards Codification
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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

No definition available.

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- Definition

Weighted average interest rate of short-term debt outstanding calculated at point in time.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
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- Definition

For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

+ References

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-Name Regulation S-K (SK)
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- Definition

For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, the maximum amount borrowed at any time during the period.

+ References

No definition available.

+ Details

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