Borrowings and Other Financing Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Series Due September 15, 2052 \| Bonds [Member]
Short-term Debt [Line Items]
Debt Instrument, Face Amount	$ 100.0
Debt Instrument, Interest Rate, Stated Percentage	4.86%
Payable to Affiliates
Short-term Debt [Line Items]
Notes Payable, Related Parties, Current	$ 0.0	$ 0.0

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