AROs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024		Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 3,218		$ 3,380
Amounts Incurred	109	[1]	10	[2]
Amounts Settled	(6)		(1)
Accretion	153		154
Cash flow revisions	239	[3]	(325)	[4]
Ending balance	3,713		3,218
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Decommissioning fund investments	3,494	[5]	3,211	[6]
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | NSP Minnesota
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Decommissioning fund investments	3,500		3,200
Electric Plant Nuclear Production Decommissioning
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	2,107		2,160
Amounts Incurred	0	[1]	0	[2]
Amounts Settled	0		0
Accretion	106		105
Cash flow revisions	263	[3]	(158)	[4]
Ending balance	2,476		2,107
Electric Plant Wind Production
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	526		514
Amounts Incurred	0	[1]	10	[2]
Amounts Settled	0		0
Accretion	19		19
Cash flow revisions	(36)	[3]	(17)	[4]
Ending balance	509		526
Electric Plant Steam, Hydro and Other Production Asbestos
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	361		348
Amounts Incurred	109	[1]	0	[2]
Amounts Settled	(6)		(1)
Accretion	18		15
Cash flow revisions	13	[3]	(1)	[4]
Ending balance	495		361
Electric Plant Electric Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	49		48
Amounts Incurred	0	[1]	0	[2]
Amounts Settled	0		0
Accretion	2		1
Cash flow revisions	0	[3]	0	[4]
Ending balance	51		49
Natural Gas Plant Gas Transmission and Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	172		307
Amounts Incurred	0	[1]	0	[2]
Amounts Settled	0		0
Accretion	8		14
Cash flow revisions	(1)	[3]	(149)	[4]
Ending balance	179		172
Common and Other Property Common Miscellaneous
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	3		3
Amounts Incurred	0	[1]	0	[2]
Amounts Settled	0		0
Accretion	0		0
Cash flow revisions	0	[3]	0	[4]
Ending balance	$ 3		$ 3

[1] Amounts incurred largely pertain to CCR coal ash regulations and new obligations associated with Sherco Solar Unit 1 , which was placed in service in 2024.

[2] Amounts incurred relate to the Northern Wind farm placed in service in NSP-Minnesota.

[3] In 2024, AROs were revised for changes in timing and estimates of cash flows. Changes were driven by updated assumptions in the NSP-Minnesota nuclear decommissioning triennial filing coupled with discount rate and escalation rate changes. Wind, steam, hydro and other production AROs were revised due to the results of the 2024 dismantling studies and changes in cost estimates to remediate ash containment facilities.

[4] In 2023, AROs were revised for changes in timing and estimates of cash flows. Revisions in wind and nuclear AROs were primarily incurred due to changes in useful lives. Changes in gas transmission and distribution AROs were a result of updated gas line mileage and number of services, as well as changes to inflation and discount rate assumptions.

[5] Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets, which also includes $246 million of equity method investments and $156 million of rabbi trust assets and other miscellaneous investments.

[6] Reported in nuclear decommissioning fund and other investments on the consolidated balance sheets, which also includes $244 million of equity investments in unconsolidated subsidiaries and $144 million of rabbi trust assets and other miscellaneous investments.