-- None. No documentation exists for this element. --

No definition available.

Name:	nspm_DefinedBenefitPlanNetProjectedBenefitPaymentsAbstract
Namespace Prefix:	nspm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the benefits expected to be paid, net of the prescription drug subsidy receipts expected to be received in the five fiscal years thereafter (the aggregate net amount of benefits expected to be paid in years 6 through 10 after the date of the latest statement of financial position).

+ References

No definition available.

Benefit Plans and Other Postretirement Benefits, Projected Benefit Payments (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Defined Contribution Plan, Administrative Expense		$ 12	$ 12	$ 12
Pension Plan
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract]
2022		118
2023		72
2024		68
2025		67
2026		64
2027-2031		292
Pension Plan \| Xcel Energy [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits		131	150	154
Pension Plan \| Xcel Energy [Member] \| Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	$ 50
Pension Plan \| NSP Minnesota [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits		34	44	47
Pension Plan \| NSP Minnesota [Member] \| Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	5
Postretirement Benefits Plan
Defined Benefit Plan, Gross Projected Benefit Payments [Abstract]
2022		6
2023		6
2024		5
2025		5
2026		5
2027-2031		18
Expected Medicare Part D Subsidies [Abstract]
2022		0
2023		0
2024		0
2025		0
2026		0
2027-2031		0
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
2022		6
2023		6
2024		5
2025		5
2026		5
2027-2031		18
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] \| Xcel Energy [Member] \| Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	9
Defined Benefit Plan, Overfunded Plan [Member] \| NSP Minnesota [Member]
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits		$ 8	$ 6	$ 8
Defined Benefit Plan, Overfunded Plan [Member] \| NSP Minnesota [Member] \| Subsequent Event
Defined Benefit Plan, Net Projected Benefit Payments [Abstract]
Payment for Pension Benefits	$ 6