Property And Plant, Net (Schedule Of Property And Plant, Net) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	$ 16,495	$ 15,426
Property, plant, and equipment, net	36,304	33,776
Depreciable Property, Plant And Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	50,790	47,179
Property, plant, and equipment, net	34,295	31,753
Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	3,556	3,452
Natural Gas and Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	938	921
Nuclear
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	5,931	5,879
Renewable Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,920	1,984
Electric distribution
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	17,629	16,458
Electric transmission
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	10,162	9,508
Natural gas
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	5,197	4,874
Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	4,457	4,103
Nuclear fuel in progress
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	268	173
Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	30	29
Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	1,741	1,320
Plant To Be Abandoned, Net
Property, Plant and Equipment [Line Items]
Property and plant, at original cost		530
Ameren Missouri
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	10,875	10,243
Property, plant, and equipment, net	18,788	17,250
Ameren Missouri | Depreciable Property, Plant And Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	28,404	25,876
Property, plant, and equipment, net	17,529	15,633
Ameren Missouri | Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	3,556	3,452
Ameren Missouri | Natural Gas and Oil Fired Electric Generation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	938	921
Ameren Missouri | Nuclear
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	5,931	5,879
Ameren Missouri | Renewable Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,901	1,973
Ameren Missouri | Electric distribution
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	9,469	8,638
Ameren Missouri | Electric transmission
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,406	2,134
Ameren Missouri | Natural gas
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	776	688
Ameren Missouri | Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,427	2,191
Ameren Missouri | Nuclear fuel in progress
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	268	173
Ameren Missouri | Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	991	914
Ameren Missouri | Plant To Be Abandoned, Net
Property, Plant and Equipment [Line Items]
Property and plant, at original cost		530
Ameren Illinois
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	5,184	4,783
Property, plant, and equipment, net	15,530	14,632
Ameren Illinois | Depreciable Property, Plant And Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	20,095	19,055
Property, plant, and equipment, net	14,911	14,272
Ameren Illinois | Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	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	19	11
Ameren Illinois | Electric distribution
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	8,160	7,820
Ameren Illinois | Electric transmission
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	5,725	5,381
Ameren Illinois | Natural gas
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	4,421	4,186
Ameren Illinois | Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	1,770	1,657
Ameren Illinois | Nuclear fuel in progress
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	0	0
Ameren Illinois | Other
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	619	360
Ameren Illinois | Plant To Be Abandoned, Net
Property, Plant and Equipment [Line Items]
Property and plant, at original cost		0
Other
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	436	400
Property, plant, and equipment, net	1,986	1,894
Other | Depreciable Property, Plant And Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	2,291	2,248
Property, plant, and equipment, net	1,855	1,848
Other | Coal Fired Electric Generation Equipment
Property, Plant and Equipment [Line Items]
Property and plant, at original cost	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	2,031	1,993
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	260	255
Other | Nuclear fuel in progress
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	$ 131	46
Other | Plant To Be Abandoned, Net
Property, Plant and Equipment [Line Items]
Property and plant, at original cost		$ 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