Property And Plant, Net (Schedule Of Property And Plant, Net) (Details) $ in Millions	Dec. 31, 2023 USD ($) equipment	Dec. 31, 2022 USD ($)
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	$ 47,179	$ 43,839
Accumulated depreciation and amortization	15,426	14,465
Property and plant, before construction work in progress	31,753	29,374
Property, plant, and equipment, net	$ 33,776	31,262
Number of combustion turbine electric generation equipment with related financing obligations | equipment	2
Gross asset value, financing obligations		125
Total accumulated depreciation, financing obligations		54
Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	$ 3,452	3,454
Plant To Be Abandoned, Net	530	582
Natural Gas and Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	921	961
Nuclear
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	5,879	5,725
Renewable Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	1,984	1,968
Electric distribution
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	16,458	15,344
Electric transmission
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	9,508	8,316
Natural gas
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	4,874	4,523
Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	4,103	3,548
Construction work in progress:	1,320	1,198
Nuclear fuel in progress
Property, Plant and Equipment [Line Items]
Construction work in progress:	173	108
Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	29	29
Ameren Missouri
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	25,876	24,518
Accumulated depreciation and amortization	10,243	9,682
Property and plant, before construction work in progress	15,633	14,836
Property, plant, and equipment, net	17,250	16,124
Ameren Missouri | Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	3,452	3,454
Plant To Be Abandoned, Net	530	582
Ameren Missouri | Natural Gas and Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	921	961
Ameren Missouri | Nuclear
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	5,879	5,725
Ameren Missouri | Renewable Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	1,973	1,957
Ameren Missouri | Electric distribution
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	8,638	7,993
Ameren Missouri | Electric transmission
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,134	1,884
Ameren Missouri | Natural gas
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	688	640
Ameren Missouri | Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,191	1,904
Construction work in progress:	914	598
Ameren Missouri | Nuclear fuel in progress
Property, Plant and Equipment [Line Items]
Construction work in progress:	173	108
Ameren Illinois
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	19,055	17,257
Accumulated depreciation and amortization	4,783	4,418
Property and plant, before construction work in progress	14,272	12,839
Property, plant, and equipment, net	14,632	13,353
Ameren Illinois | Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Plant To Be Abandoned, Net	0	0
Ameren Illinois | Natural Gas and Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Ameren Illinois | Nuclear
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Ameren Illinois | Renewable Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	11	11
Ameren Illinois | Electric distribution
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	7,820	7,351
Ameren Illinois | Electric transmission
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	5,381	4,617
Ameren Illinois | Natural gas
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	4,186	3,883
Ameren Illinois | Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	1,657	1,395
Construction work in progress:	360	514
Ameren Illinois | Nuclear fuel in progress
Property, Plant and Equipment [Line Items]
Construction work in progress:	0	0
Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,248	2,064
Accumulated depreciation and amortization	400	365
Property and plant, before construction work in progress	1,848	1,699
Property, plant, and equipment, net	1,894	1,785
Other | Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Plant To Be Abandoned, Net	0	0
Other | Natural Gas and Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Other | Nuclear
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Other | Renewable Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Other | Electric distribution
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Other | Electric transmission
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	1,993	1,815
Other | Natural gas
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Other | Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	255	249
Construction work in progress:	46	86
Other | Nuclear fuel in progress
Property, Plant and Equipment [Line Items]
Construction work in progress:	$ 0	$ 0
Minimum | Electric distribution
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Minimum | Electric transmission
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	50 years
Minimum | Natural gas
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Minimum | Other
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum | Electric generation
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum | Electric distribution
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	80 years
Maximum | Electric transmission
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	75 years
Maximum | Natural gas
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	80 years
Maximum | Other
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	55 years
Maximum | Electric generation
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	72 years
Maximum | Ameren Missouri | Electric generation
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	150 years