Property And Plant, Net (Tables)

12 Months Ended

Dec. 31, 2023

Property, Plant and Equipment [Abstract]

The following table presents components of “Property, plant, and equipment, net” at December 31, 2023 and 2022:


	Ameren Missouri		Ameren Illinois		Other		Ameren
2023
Property, plant, and equipment at original cost(a):
Electric generation:
Coal(b)	$	3,452	$	—	$	—	$	3,452
Natural gas	921		—		—		921
Nuclear	5,879		—		—		5,879
Renewable(c)	1,973		11		—		1,984
Electric distribution	8,638		7,820		—		16,458
Electric transmission	2,134		5,381		1,993		9,508
Natural gas	688		4,186		—		4,874
Other(d)	2,191		1,657		255		4,103
	25,876		19,055		2,248		47,179
Less: Accumulated depreciation and amortization	10,243		4,783		400		15,426
	15,633		14,272		1,848		31,753
Construction work in progress:
Nuclear fuel in progress	173		—		—		173
Other	914		360		46		1,320
Plant to be abandoned, net(e)	530		—		—		530
Property, plant, and equipment, net	$	17,250	$	14,632	$	1,894	$	33,776
2022
Property, plant, and equipment at original cost(a):
Electric generation:
Coal(b)(f)	$	3,454	$	—	$	—	$	3,454
Natural gas	961		—		—		961
Nuclear	5,725		—		—		5,725
Renewable(c)	1,957		11		—		1,968
Electric distribution	7,993		7,351		—		15,344
Electric transmission	1,884		4,617		1,815		8,316
Natural gas	640		3,883		—		4,523
Other(d)	1,904		1,395		249		3,548
	24,518		17,257		2,064		43,839
Less: Accumulated depreciation and amortization(f)	9,682		4,418		365		14,465
	14,836		12,839		1,699		29,374
Construction work in progress:
Nuclear fuel in progress	108		—		—		108
Other	598		514		86		1,198
Plant to be abandoned, net(e)	582		—		—		582
Property, plant, and equipment, net	$	16,124	$	13,353	$	1,785	$	31,262

(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; 20 to 80 years for natural gas; and 2 to 55 years for other.

(b)Includes $29 million of oil-fired generation at December 31, 2023 and 2022.

(c)Renewable includes hydroelectric, wind, solar, and methane gas generation facilities.

(d)Other property, plant, and equipment includes assets used to support electric and natural gas services.

(e)Represents the net book value of the Rush Island Energy Center as Ameren Missouri expects to retire the energy center significantly in advance of its previously expected useful life and in the near term. See Plant to be Abandoned, Net under Note 1 – Summary of Significant Accounting Policies, NSR and Clean Air Act Litigation under Note 14 – Commitments and Contingencies, and Securitization of the Rush Island Energy Center under Note 2 – Rate and Regulatory Matters for additional information on the planned accelerated retirement of the Rush Island Energy Center.

(f)Original cost amounts include two CTs that had related financing obligations. The financing obligation for the Peno Creek CT Energy Center was settled in December 2022, while the financing obligation for the Audrain CT Energy Center was settled in January 2023. The gross cumulative plant asset values related to outstanding financing obligations as of December 31, 2022 was $125 million and the related accumulated depreciation was $54 million. See Note 5 – Long-term Debt and Equity Financings for additional information on these agreements.

Schedule of Capitalized Software and Deferred Cloud Implementation Costs

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 Expense						Gross Carrying Value				Accumulated Amortization
	2023		2022		2021		2023		2022		2023		2022
Capitalized software costs:
Ameren	$	212	$	159	$	125	$	1,823	$	1,443	$	(1,126)	$	(914)
Ameren Missouri	114		85		66		795		613		(453)		(339)
Ameren Illinois	92		69		53		786		601		(452)		(360)
Deferred cloud implementation costs:
Ameren	$	17	$	15	$	13	$	142	$	106	$	(51)	$	(34)
Ameren Missouri	8		7		6		63		48		(23)		(15)
Ameren Illinois	9		8		6		76		54		(26)		(17)

Schedule of Capitalized Software, Future Amortization Expense

Annual amortization expense for capitalized software placed in service as of December 31, 2023, is estimated to be as follows:


	2024		2025		2026		2027		2028
Ameren	$	202	$	147	$	106	$	79	$	45
Ameren Missouri	106		76		52		38		22
Ameren Illinois	90		65		51		38		23