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Property And Plant, Net
12 Months Ended
Dec. 31, 2025
Property, Plant and Equipment [Abstract]  
PROPERTY AND PLANT, NET PROPERTY, PLANT, AND EQUIPMENT, NET
The following table presents components of “Property, plant, and equipment, net” at December 31, 2025 and 2024:
Ameren
Missouri
Ameren
Illinois
OtherAmeren
2025
Property, plant, and equipment at original cost(a):
Electric generation:
Coal(b)
$3,640 $ $ $3,640 
Natural gas948   948 
Nuclear6,255   6,255 
Renewable(c)
3,072 19  3,091 
Electric distribution10,205 8,758  18,963 
Electric transmission2,479 6,247 2,184 10,910 
Natural gas837 4,642  5,479 
Other(d)
2,132 1,412 40 3,584 
29,568 21,078 2,224 52,870 
Less: Accumulated depreciation and amortization11,090 5,219 260 16,569 
18,478 15,859 1,964 36,301 
Construction work in progress:
Nuclear fuel in progress194   194 
Other1,932 708 178 2,818 
Property, plant, and equipment, net$20,604 $16,567 $2,142 $39,313 
2024
Property, plant, and equipment at original cost(a):
Electric generation:
Coal(b)
$3,556 $— $— $3,556 
Natural gas938 — — 938 
Nuclear5,931 — — 5,931 
Renewable(c)
2,901 19 — 2,920 
Electric distribution9,469 8,160 — 17,629 
Electric transmission2,406 5,725 2,031 10,162 
Natural gas776 4,421 — 5,197 
Other(d)
2,427 1,770 260 4,457 
28,404 20,095 2,291 50,790 
Less: Accumulated depreciation and amortization10,875 5,184 436 16,495 
17,529 14,911 1,855 34,295 
Construction work in progress:
Nuclear fuel in progress268 — — 268 
Other991 619 131 1,741 
Property, plant, and equipment, net$18,788 $15,530 $1,986 $36,304 
(a)The estimated lives for each asset group are as follows: 5 to 72 years for electric generation, excluding Ameren Missouri’s hydroelectric generating assets, which have useful lives of up to 150 years; 20 to 80 years for electric distribution; 50 to 75 years for electric transmission; 15 to 80 years for natural gas; and 2 to 55 years for other.
(b)Includes $30 million of oil-fired generation at December 31, 2025 and 2024.
(c)Renewable includes hydroelectric, wind, solar, and methane gas generation facilities.
(d)Other property, plant, and equipment includes assets used to support electric distribution, electric transmission, and natural gas services.
Capitalized software costs are classified within “Property, Plant, and Equipment, Net” on the balance sheet and are amortized on a straight-line basis over the expected period of benefit, ranging from 2 to 15 years, with the amortization expense included in “Depreciation and amortization” on the statement of income. Deferred cloud implementation costs are classified within “Other Assets” on the balance sheet and are amortized on a straight-line basis over the term of the associated hosting arrangement, ranging from 5 to 15 years, with the amortization expense included in “Other operations and maintenance” on the statement of income. The following table presents the amortization expense, gross carrying value, and related accumulated amortization of capitalized software and deferred cloud implementation costs by year:
Amortization ExpenseGross Carrying ValueAccumulated Amortization
2025202420232025202420252024
Capitalized software costs:
Ameren$222 $224 $212 $1,174 $1,996 $(572)$(1,348)
Ameren Missouri113 118 114 562 881 (290)(567)
Ameren Illinois101 100 92 570 867 (261)(552)
Deferred cloud implementation costs:
Ameren$19 $20 $17 $142 $157 $(59)$(71)
Ameren Missouri8 63 71 (28)(32)
Ameren Illinois10 10 76 82 (29)(36)
Annual amortization expense for capitalized software classified as in service as of December 31, 2025, is estimated to be as follows:
20262027202820292030
Ameren$198 $152 $98 $63 $32 
Ameren Missouri96 73 46 28 14 
Ameren Illinois96 73 49 32 17