Benefit Plans and Other Postretirement Benefits (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended
		Jan. 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Plan [Member]
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost			$ 5	$ 8	$ 9	$ 15
Interest Cost	[1]		14	11	29	21
Expected return on Plan Assets	[1]		(19)	(20)	(38)	(39)
Amortization of prior service credit	[1]				0	0
Amortization of net loss	[1]		1	5	1	11
Net periodic benefit cost			1	4	1	8
Effects of regulation			3	2	6	5
Net benefit cost recognized for financial reporting			4	6	7	13
Pension Plan [Member] | Xcel Energy Inc.
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Total contributions to the pension plans during the period		$ 50
Other Postretirement Benefits Plan [Member]
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service cost			0	0	0	0
Interest Cost	[1]		4	3	8	6
Expected return on Plan Assets	[1]		(4)	(4)	(8)	(8)
Amortization of prior service credit	[1]				0	(1)
Amortization of net loss	[1]		1	1	1	1
Net periodic benefit cost			1	0	1	(2)
Effects of regulation			0	0	0	1
Net benefit cost recognized for financial reporting			$ 1	$ 0	$ 1	$ (1)

[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.