Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating expenses
Accounts payable to affiliates	$ 13	$ 21
NSP-Minnesota
Operating expenses
Other receivables	28	0
Accounts payable to affiliates	0	9
PSCo
Operating expenses
Other receivables	2	1
Accounts payable to affiliates	0	0
Other subsidiaries of Xcel Energy Inc.
Operating expenses
Other receivables	3	12
Accounts payable to affiliates	13	13
Xcel Energy [Member]
Operating expenses
Other receivables	33	13
Accounts payable to affiliates	13	22
Purchased Power
Operating expenses
Costs and Expenses, Related Party	384	424	$ 445
Transmission Expense
Operating expenses
Costs and Expenses, Related Party	75	69	68
Natural Gas Purchase for Resale
Operating expenses
Costs and Expenses, Related Party	1	1	0
Other Expense
Operating expenses
Costs and Expenses, Related Party	129	119	114
Interest Expense
Operating expenses
Costs and Expenses, Related Party	1	1	1
Electricity, US Regulated | Xcel Energy [Member]
Operating expenses
Revenues	216	204	202
Interest and Other Income	$ 0	$ 1	$ 0