Borrowings and Other Financing Instruments (Details) - Series Due June 15, 2053 - Bonds [Member] $ in Millions	Sep. 30, 2023 USD ($)
Short-term Debt [Line Items]
Debt Instrument, Face Amount	$ 125
Debt Instrument, Interest Rate, Stated Percentage	5.30%

Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant