Benefit Plans and Other Postretirement Benefits (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
		Jan. 31, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pension Plan [Member]
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost			$ 1	$ 2	$ 5	$ 5
Interest cost (a)	[1]		6	5	17	17
Expected return on plan assets (a)	[1]		(9)	(8)	(25)	(24)
Amortization of net loss (gain) (a)	[1]		1	0	2	1
Net periodic benefit cost (credit)			(1)	(1)	(1)	(1)
Contributions to pension plans		$ 3
Defined Benefit Plan Credits Not Recognized Due To Effects of Regulation			0	1	(1)	3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)			$ (1)	$ 0	(2)	2
Pension Plan [Member] | Xcel Energy Inc.
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Contributions to pension plans		$ 100
Other Postretirement Benefits Plan [Member]
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost					0	0
Interest cost (a)	[1]				1	1
Expected return on plan assets (a)	[1]				(1)	(1)
Amortization of net loss (gain) (a)	[1]				0	0
Net periodic benefit cost (credit)					0	0
Defined Benefit Plan Credits Not Recognized Due To Effects of Regulation					0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)					$ 0	$ 0

[1] The components of net periodic cost other than the service cost component are included in the line item “Other income (expense), net” in the statements of income or capitalized on the balance sheets as a regulatory asset.