Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
NSP-Minnesota
Operating expenses
Other Receivables	$ 0	$ 2
Accounts Payable, Other	5	0
NSP-Wisconsin
Operating expenses
Other Receivables	0	0
Accounts Payable, Other	1	2
SPS
Operating expenses
Other Receivables	0	0
Accounts Payable, Other	11	11
Other subsidiaries of Xcel Energy Inc.
Operating expenses
Other Receivables	28	9
Accounts Payable, Other	66	62
Xcel Energy [Member]
Operating expenses
Other Receivables	28	11
Accounts Payable, Other	83	75
Other Expense
Operating expenses
Costs and Expenses, Related Party	679	670	$ 617
Interest Expense
Operating expenses
Costs and Expenses, Related Party	5	2	0
Other Revenue | Xcel Energy [Member]
Operating expenses
Total revenues	5	5	5
Electricity, US Regulated | Xcel Energy [Member]
Operating expenses
Interest and Other Income	$ 2	$ 0	$ 0