Benefit Plans and Other Postretirement Benefits (Details) $ in Millions		1 Months Ended	3 Months Ended
		Jan. 31, 2022 USD ($) Plan	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)
Pension Plan [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service Cost			$ 7	$ 7
Interest cost (a)	[1]		6	6
Expected return on plan assets (a)	[1]		(12)	(13)
Amortization of prior service credit (a)	[1]		0	0
Amortization of net loss (a)	[1]		6	9
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[2]		(1)	0
Net periodic benefit cost			6	9
Effects of regulation			1	(1)
Net benefit cost recognized for financial reporting			7	8
Total contributions to the pension plans during the period		$ 5
Pension Plan [Member] | Xcel Energy Inc.
Components of Net Periodic Benefit Cost [Abstract]
Total contributions to the pension plans during the period		$ 50
Number of Xcel Energy's pension plans to which contributions were made | Plan		4
Other Postretirement Benefits Plan [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service Cost			0	0
Interest cost (a)	[1]		1	1
Expected return on plan assets (a)	[1]		0	0
Amortization of prior service credit (a)	[1]		(1)	(1)
Amortization of net loss (a)	[1]		0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[2]		0	0
Net periodic benefit cost			0	0
Effects of regulation			0	0
Net benefit cost recognized for financial reporting			$ 0	$ 0

[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.

[2] In the first quarter of 2022, NSP-Minnesota recognized $1 million in settlement charge true-ups related to fourth quarter 2021.