Borrowings and Other Financing Instruments Borrowings and Other Financing Instruments, Term Loan (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Amount outstanding at period end		$ 1,597,000		$ 1,038,000
364-Day Term Loan [Member] | Xcel Energy Inc.
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		500,000
Amount outstanding at period end		500,000
Available		$ 0
364-Day Term Loan [Member] | Parent
Short-term Debt [Line Items]
Line of Credit Facility, Expiration Period		364 days
Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	[1]	$ 3,100,000
Available		1,972,000
Revolving Credit Facility [Member] | Xcel Energy Inc.
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	[1]	1,250,000	$ 1,000,000
Available		$ 618,000
Revolving Credit Facility [Member] | Parent
Short-term Debt [Line Items]
Required debt to total capitalization ratio				65.00%
basis points				50.0
Basis points related to commitment fee				10

[1] ^(a)  Expires in June 2024.