Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	$ 9	$ 9
Accounts payable	16	17
NSP-Minnesota
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	2	3
Accounts payable	0	0
PSCo
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	7	6
Accounts payable	0	0
Other Subsidiaries of Xcel Energy Inc.
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts receivable	0	0
Accounts payable	16	17
Other Expense [Member]
Operating expenses [Abstract]
Costs and Expenses, Related Party	$ 209	$ 200	$ 192