Borrowings and Other Financing Instruments Term Loan (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Short-term Debt [Line Items]
Amount outstanding at period end	$ 158		$ 1,005
Proceeds from issuance of common stock	156	$ 13
Letter of Credit
Short-term Debt [Line Items]
Amount outstanding at period end	$ 39		$ 19

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.

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