Commitments and Contingencies NSP-Minnesota-Sherco (Details) $ in Millions	1 Months Ended
Jan. 31, 2021 USD ($)
Rate Matters [Abstract]
Sherco Dissallowance	$ 22
NSP-Minnesota
Rate Matters [Abstract]
Customer refund of previously recovered purchased power costs	$ 17

Customer refund of previously recovered purchased power costs

No definition available.

Name:	xel_Customerrefundofpreviouslyrecoveredpurchasedpowercosts
Namespace Prefix:	xel_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration