Segment Information (Schedule Of Segment Reporting Information By Segment) (Details) - USD ($)
$ in Millions |
3 Months Ended |
6 Months Ended |
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
$ 2,221
|
$ 1,693
|
$ 4,318
|
$ 3,509
|
| Revenues |
2,221
|
1,693
|
4,318
|
3,509
|
| Fuel and purchased power |
(794)
|
(327)
|
(1,296)
|
(655)
|
| Natural gas purchased for resale |
(39)
|
(33)
|
(208)
|
(184)
|
| Other operations and maintenance expenses |
(460)
|
(465)
|
(945)
|
(935)
|
| Depreciation and amortization |
(386)
|
(376)
|
(753)
|
(737)
|
| Taxes other than income taxes |
(131)
|
(131)
|
(275)
|
(266)
|
| Other Income, Net |
96
|
103
|
181
|
192
|
| Interest charges |
(187)
|
(165)
|
(362)
|
(319)
|
| Income taxes |
(43)
|
(39)
|
(93)
|
(83)
|
| Noncontrolling interests - preferred stock dividends |
(2)
|
(2)
|
(3)
|
(3)
|
| Net income (loss) attributable to Ameren common shareholders |
275
|
258
|
564
|
519
|
| Interest income |
10
|
13
|
21
|
21
|
| Capital expenditures |
1,066
|
1,002
|
2,130
|
1,892
|
| Union Electric Company |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
1,340
|
888
|
2,297
|
1,663
|
| Fuel and purchased power |
(614)
|
(189)
|
(944)
|
(355)
|
| Natural gas purchased for resale |
(9)
|
(9)
|
(39)
|
(37)
|
| Other operations and maintenance expenses |
(238)
|
(247)
|
(488)
|
(501)
|
| Taxes other than income taxes |
(89)
|
(91)
|
(178)
|
(178)
|
| Other Income, Net |
47
|
49
|
90
|
93
|
| Interest charges |
(70)
|
(63)
|
(130)
|
(125)
|
| Income taxes |
(7)
|
(1)
|
(11)
|
(2)
|
| Noncontrolling interests - preferred stock dividends |
(1)
|
(1)
|
(2)
|
(2)
|
| Net income (loss) attributable to Ameren common shareholders |
150
|
128
|
192
|
153
|
| Ameren Illinois Company |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
843
|
766
|
1,943
|
1,766
|
| Revenues |
843
|
766
|
1,943
|
1,766
|
| Purchased Power |
(183)
|
(141)
|
(358)
|
(305)
|
| Natural gas purchased for resale |
(30)
|
(24)
|
(169)
|
(147)
|
| Other operations and maintenance expenses |
(225)
|
(224)
|
(461)
|
(434)
|
| Depreciation and amortization |
(163)
|
(154)
|
(322)
|
(307)
|
| Taxes other than income taxes |
(37)
|
(35)
|
(88)
|
(79)
|
| Other Income, Net |
37
|
37
|
71
|
68
|
| Interest charges |
(63)
|
(60)
|
(125)
|
(115)
|
| Income taxes |
(41)
|
(40)
|
(117)
|
(107)
|
| Noncontrolling interests - preferred stock dividends |
(1)
|
(1)
|
(1)
|
(1)
|
| Net income (loss) attributable to Ameren common shareholders |
137
|
124
|
373
|
339
|
| Net income available to common shareholder |
137
|
124
|
373
|
339
|
| Interest income |
8
|
9
|
17
|
15
|
| Capital expenditures |
379
|
344
|
742
|
717
|
| Operating Segments | Union Electric Company |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
1,332
|
879
|
2,282
|
1,647
|
| Revenues |
1,340
|
888
|
2,297
|
1,663
|
| Fuel and purchased power |
(614)
|
(189)
|
(944)
|
(355)
|
| Natural gas purchased for resale |
(9)
|
(9)
|
(39)
|
(37)
|
| Other operations and maintenance expenses |
(238)
|
(247)
|
(488)
|
(501)
|
| Depreciation and amortization |
(209)
|
(208)
|
(403)
|
(403)
|
| Taxes other than income taxes |
(89)
|
(91)
|
(178)
|
(178)
|
| Other Income, Net |
47
|
49
|
90
|
93
|
| Interest charges |
(70)
|
(63)
|
(130)
|
(125)
|
| Income taxes |
(7)
|
(1)
|
(11)
|
(2)
|
| Noncontrolling interests - preferred stock dividends |
(1)
|
(1)
|
(2)
|
(2)
|
| Net income (loss) attributable to Ameren common shareholders |
|
|
192
|
153
|
| Net income available to common shareholder |
150
|
128
|
|
|
| Interest income |
2
|
3
|
4
|
5
|
| Capital expenditures |
667
|
638
|
1,325
|
1,104
|
| Operating Segments | Ameren Illinois Electric Distribution |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
570
|
509
|
1,140
|
1,015
|
| Revenues |
573
|
509
|
1,145
|
1,015
|
| Fuel and purchased power |
(223)
|
(168)
|
(435)
|
(360)
|
| Natural gas purchased for resale |
0
|
0
|
0
|
0
|
| Other operations and maintenance expenses |
(156)
|
(153)
|
(322)
|
(289)
|
| Depreciation and amortization |
(93)
|
(93)
|
(184)
|
(186)
|
| Taxes other than income taxes |
(20)
|
(19)
|
(41)
|
(36)
|
| Other Income, Net |
23
|
27
|
46
|
49
|
| Interest charges |
(26)
|
(26)
|
(52)
|
(48)
|
| Income taxes |
(13)
|
(15)
|
(29)
|
(27)
|
| Noncontrolling interests - preferred stock dividends |
(1)
|
(1)
|
(1)
|
(1)
|
| Net income (loss) attributable to Ameren common shareholders |
|
|
127
|
117
|
| Net income available to common shareholder |
64
|
61
|
|
|
| Interest income |
8
|
9
|
16
|
15
|
| Capital expenditures |
153
|
132
|
320
|
316
|
| Operating Segments | Ameren Illinois Natural Gas |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
158
|
148
|
569
|
539
|
| Revenues |
158
|
148
|
569
|
539
|
| Fuel and purchased power |
0
|
0
|
0
|
0
|
| Natural gas purchased for resale |
(30)
|
(24)
|
(169)
|
(147)
|
| Other operations and maintenance expenses |
(55)
|
(59)
|
(110)
|
(117)
|
| Depreciation and amortization |
(33)
|
(33)
|
(65)
|
(66)
|
| Taxes other than income taxes |
(16)
|
(15)
|
(45)
|
(41)
|
| Other Income, Net |
5
|
7
|
10
|
14
|
| Interest charges |
(16)
|
(15)
|
(31)
|
(30)
|
| Income taxes |
(3)
|
(3)
|
(41)
|
(40)
|
| Noncontrolling interests - preferred stock dividends |
0
|
0
|
0
|
0
|
| Net income (loss) attributable to Ameren common shareholders |
|
|
118
|
112
|
| Net income available to common shareholder |
10
|
6
|
|
|
| Interest income |
0
|
0
|
0
|
0
|
| Capital expenditures |
88
|
59
|
147
|
119
|
| Operating Segments | Ameren Transmission |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
161
|
157
|
327
|
308
|
| Revenues |
208
|
191
|
418
|
376
|
| Fuel and purchased power |
0
|
0
|
0
|
0
|
| Natural gas purchased for resale |
0
|
0
|
0
|
0
|
| Other operations and maintenance expenses |
(18)
|
(16)
|
(37)
|
(35)
|
| Depreciation and amortization |
(49)
|
(40)
|
(97)
|
(79)
|
| Taxes other than income taxes |
(3)
|
(2)
|
(4)
|
(4)
|
| Other Income, Net |
10
|
4
|
17
|
6
|
| Interest charges |
(29)
|
(29)
|
(58)
|
(58)
|
| Income taxes |
(33)
|
(29)
|
(64)
|
(55)
|
| Noncontrolling interests - preferred stock dividends |
0
|
0
|
0
|
0
|
| Net income (loss) attributable to Ameren common shareholders |
|
|
175
|
151
|
| Net income available to common shareholder |
86
|
79
|
|
|
| Interest income |
0
|
1
|
1
|
1
|
| Capital expenditures |
158
|
175
|
331
|
341
|
| Operating Segments | Ameren Illinois Company | Ameren Illinois Electric Distribution |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
573
|
509
|
1,145
|
1,015
|
| Revenues |
573
|
509
|
1,145
|
1,015
|
| Purchased Power |
(223)
|
(168)
|
(435)
|
(360)
|
| Natural gas purchased for resale |
0
|
0
|
0
|
0
|
| Other operations and maintenance expenses |
(156)
|
(153)
|
(322)
|
(289)
|
| Depreciation and amortization |
(93)
|
(93)
|
(184)
|
(186)
|
| Taxes other than income taxes |
(20)
|
(19)
|
(41)
|
(36)
|
| Other Income, Net |
23
|
27
|
46
|
49
|
| Interest charges |
(26)
|
(26)
|
(52)
|
(48)
|
| Income taxes |
(13)
|
(15)
|
(29)
|
(27)
|
| Noncontrolling interests - preferred stock dividends |
(1)
|
(1)
|
(1)
|
(1)
|
| Net income available to common shareholder |
64
|
61
|
127
|
117
|
| Interest income |
8
|
9
|
16
|
15
|
| Capital expenditures |
153
|
132
|
320
|
316
|
| Operating Segments | Ameren Illinois Company | Ameren Illinois Natural Gas |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
158
|
148
|
569
|
539
|
| Revenues |
158
|
148
|
569
|
539
|
| Purchased Power |
0
|
0
|
0
|
0
|
| Natural gas purchased for resale |
(30)
|
(24)
|
(169)
|
(147)
|
| Other operations and maintenance expenses |
(55)
|
(59)
|
(110)
|
(117)
|
| Depreciation and amortization |
(33)
|
(33)
|
(65)
|
(66)
|
| Taxes other than income taxes |
(16)
|
(15)
|
(45)
|
(41)
|
| Other Income, Net |
5
|
7
|
10
|
14
|
| Interest charges |
(16)
|
(15)
|
(31)
|
(30)
|
| Income taxes |
(3)
|
(3)
|
(41)
|
(40)
|
| Noncontrolling interests - preferred stock dividends |
0
|
0
|
0
|
0
|
| Net income available to common shareholder |
10
|
6
|
118
|
112
|
| Interest income |
0
|
0
|
0
|
0
|
| Capital expenditures |
88
|
59
|
147
|
119
|
| Operating Segments | Ameren Illinois Company | Ameren Illinois Transmission |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| External revenues |
112
|
109
|
229
|
212
|
| Revenues |
152
|
136
|
306
|
267
|
| Purchased Power |
0
|
0
|
0
|
0
|
| Natural gas purchased for resale |
0
|
0
|
0
|
0
|
| Other operations and maintenance expenses |
(14)
|
(12)
|
(29)
|
(28)
|
| Depreciation and amortization |
(37)
|
(28)
|
(73)
|
(55)
|
| Taxes other than income taxes |
(1)
|
(1)
|
(2)
|
(2)
|
| Other Income, Net |
9
|
3
|
15
|
5
|
| Interest charges |
(21)
|
(19)
|
(42)
|
(37)
|
| Income taxes |
(25)
|
(22)
|
(47)
|
(40)
|
| Noncontrolling interests - preferred stock dividends |
0
|
0
|
0
|
0
|
| Net income available to common shareholder |
63
|
57
|
128
|
110
|
| Interest income |
0
|
0
|
1
|
0
|
| Capital expenditures |
138
|
153
|
275
|
282
|
| Other |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Other operations and maintenance expenses |
(8)
|
(3)
|
(16)
|
(17)
|
| Depreciation and amortization |
(2)
|
(2)
|
(4)
|
(3)
|
| Taxes other than income taxes |
(3)
|
(4)
|
(7)
|
(7)
|
| Other Income, Net |
12
|
18
|
20
|
38
|
| Interest charges |
(47)
|
(34)
|
(93)
|
(66)
|
| Income taxes |
13
|
9
|
52
|
41
|
| Noncontrolling interests - preferred stock dividends |
0
|
0
|
0
|
0
|
| Net income (loss) attributable to Ameren common shareholders |
|
|
(48)
|
(14)
|
| Net income available to common shareholder |
(35)
|
(16)
|
|
|
| Interest income |
1
|
2
|
2
|
8
|
| Capital expenditures |
3
|
2
|
5
|
4
|
| Intersegment Eliminations |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
(58)
|
(43)
|
(111)
|
(84)
|
| Revenues |
(58)
|
(43)
|
(111)
|
(84)
|
| Fuel and purchased power |
43
|
30
|
83
|
60
|
| Natural gas purchased for resale |
0
|
0
|
0
|
0
|
| Other operations and maintenance expenses |
15
|
13
|
28
|
24
|
| Depreciation and amortization |
0
|
0
|
0
|
0
|
| Taxes other than income taxes |
0
|
0
|
0
|
0
|
| Other Income, Net |
(1)
|
(2)
|
(2)
|
(8)
|
| Interest charges |
1
|
2
|
2
|
8
|
| Income taxes |
0
|
0
|
0
|
0
|
| Noncontrolling interests - preferred stock dividends |
0
|
0
|
0
|
0
|
| Interest income |
(1)
|
(2)
|
(2)
|
(8)
|
| Capital expenditures |
(3)
|
(4)
|
2
|
8
|
| Intersegment Eliminations | Union Electric Company |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
(8)
|
(9)
|
(15)
|
(16)
|
| Intersegment Eliminations | Ameren Illinois Electric Distribution |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
(3)
|
0
|
(5)
|
0
|
| Intersegment Eliminations | Ameren Illinois Natural Gas |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
0
|
0
|
0
|
0
|
| Intersegment Eliminations | Ameren Transmission |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
(47)
|
(34)
|
(91)
|
(68)
|
| Intersegment Eliminations | Ameren Illinois Company |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
(40)
|
(27)
|
(77)
|
(55)
|
| Revenues |
(40)
|
(27)
|
(77)
|
(55)
|
| Purchased Power |
(40)
|
(27)
|
(77)
|
(55)
|
| Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Electric Distribution |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
0
|
0
|
0
|
0
|
| Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Natural Gas |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
0
|
0
|
0
|
0
|
| Intersegment Eliminations | Ameren Illinois Company | Ameren Illinois Transmission |
|
|
|
|
| Segment Reporting Information [Line Items] |
|
|
|
|
| Intersegment revenues |
$ (40)
|
$ (27)
|
$ (77)
|
$ (55)
|