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Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2024

Property, Plant and Equipment [Abstract]

Schedule of Property Plant and Equipment

The service life ranges and weighted average remaining service life of PPE as at December 31 were as follows.

						2024									2023
(years)						Service Life Ranges			Weighted Average Remaining Service Life						Service Life Ranges			Weighted Average Remaining Service Life
Distribution
Electric						5-80			32						5-80			31
Gas						18-83			37						18-95			38
Transmission
Electric						20-85			42						20-90			41
Gas						10-80			35						10-85			36
Generation						2-95			22						2-95			23
Other						3-80			13						3-80			10

($ millions)						Cost						Accumulated Depreciation						Net Book Value
2024
Distribution
Electric						15,771						(4,078)						11,693
Gas						7,148						(1,866)						5,282
Transmission
Electric						23,084						(4,865)						18,219
Gas						2,937						(894)						2,043
Generation						8,056						(3,110)						4,946
Other						5,014						(1,809)						3,205
Assets under construction						3,578						—						3,578
Land						490						—						490
						66,078						(16,622)						49,456

2023
Distribution
Electric						14,352						(3,708)						10,644
Gas						6,682						(1,736)						4,946
Transmission
Electric						19,886						(4,267)						15,619
Gas						2,751						(843)						1,908
Generation						7,192						(2,739)						4,453
Other						4,444						(1,645)						2,799
Assets under construction						2,581						—						2,581
Land						435						—						435
						58,323						(14,938)						43,385

Schedule of Jointly-Owned Facilities

As at December 31, 2024, interests in jointly owned facilities consisted of the following.

			Ownership												Accumulated						Net Book
($ millions, except as indicated)			(%)						Cost						Depreciation						Value
Transmission Facilities			Various						1,704						(489)						1,215
Springerville Common Facilities			86.0						580						(344)						236
Springerville Coal Handling Facilities			83.0						299						(154)						145
Four Corners Units 4 and 5 ("Four Corners")			7.0						311						(155)						156
Gila River Common Facilities			50.0						131						(52)						79
Luna Energy Facility ("Luna")			33.3						101						3						104
									3,126						(1,191)						1,935

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- References

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- Definition

Tabular disclosure of proportionate interests in jointly owned utility plants. Includes the amount of plants in service, the accumulated provision for depreciation (if available), the amount of plants under construction, and the proportionate share. The amounts presented may be further subdivided to show amounts applicable to plant subcategories (for example, production, transmission, distribution). Includes statements that the amounts represent the utility's share in each joint plant and that it must provide its own financing. Information concerning two or more generating plants on the same site may be combined. States that the utility's share of direct expenses of the joint plants is included in the corresponding operating expenses on its income statement (for example, fuel, maintenance of plant, other operating expense). If the share of direct expenses is charged to purchased power, then disclose the amount so charged and the proportionate amounts charged to specific operating expenses on the records maintained for the joint plants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 360
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479070/980-360-S99-1

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- Definition

Tabular disclosure of public utility physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation expense and method used, including composite depreciation, and accumulated depreciation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 980
-SubTopic 20
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481834/980-20-45-1

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