Benefit Plans and Other Postretirement Benefits (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended
		Jan. 31, 2024	Mar. 31, 2024	Mar. 31, 2023
Pension Plan [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost			$ 19	$ 18
Interest Cost	[1]		38	40
Expected Return on Plan Assets	[1]		(52)	(52)
Amortization of Net Loss	[1]		7	5
Net periodic benefit cost (credit)			12	11
Effects of regulation			4	5
Net benefit cost (credit) recognized for financial reporting			16	16
Pension Plan [Member] | Parent Company
Components of Net Periodic Benefit Cost [Abstract]
Contributions to Xcel Energy's pension plans		$ 100
Other Postretirement Benefits Plan [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost			0	0
Interest Cost	[1]		5	5
Expected Return on Plan Assets	[1]		(4)	(4)
Amortization of Net Loss	[1]		1	1
Net periodic benefit cost (credit)			2	2
Effects of regulation			0	0
Net benefit cost (credit) recognized for financial reporting			$ 2	$ 2

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