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Property, Plant and Equipment (Tables) | 12 Months Ended
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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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- 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 + Details
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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 + Details
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