Benefit Plans and Other Postretirement Benefits, Projected Benefit Payments (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Defined Contribution Plan, Administrative Expense			$ 2	$ 2	$ 2
Pension Plan [Member]
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract]
2021			15
2022			11
2023			11
2024			11
2025			11
2026-2030			54
Pension Plan [Member] | NSP Wisconsin [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits			5	7	7
Pension Plan [Member] | Xcel Energy [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits			131	150	154
Pension Plan [Member] | Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	$ 50
Pension Plan [Member] | Subsequent Event | NSP Wisconsin [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	1
Pension Plan [Member] | Subsequent Event | Xcel Energy [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract]
2021			1
2022			1
2023			1
2024			1
2025			1
2026-2030			3
Expected Medicare Part D Subsidies [Abstract]
2021			0
2022			0
2023			0
2024			0
2025			0
2026-2030			0
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
2021			1
2022			1
2023			1
2024			1
2025			1
2026-2030			3
Defined Benefit Plan, Overfunded Plan [Member] | NSP Wisconsin [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits			2	1	1
Defined Benefit Plan, Overfunded Plan [Member] | Xcel Energy [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits			$ 15	$ 11	$ 15
Defined Benefit Plan, Overfunded Plan [Member] | Subsequent Event | NSP Wisconsin [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	1
Defined Benefit Plan, Overfunded Plan [Member] | Subsequent Event | Xcel Energy [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	$ 9