v3.25.2
Reportable Segments (Schedule of Financial Information by Reportable Segments, Consumers) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Segment Reporting Information [Line Items]          
Operating Revenue $ 1,838 $ 1,607 $ 4,285 $ 3,783  
Power supply cost 603 479 1,218 967  
Operating Income 317 283 811 695  
Total other income 137 113 187 199  
Total interest charges 199 173 385 350  
Income (Loss) Before Income Taxes 255 223 613 544  
Income Tax Expense 62 41 125 99  
Net Income 201 198 505 485  
Other segment items 5 13 12 35  
Net Income (Loss) Available to Common Stockholders 198 195 500 480  
Total assets 37,699 34,355 37,699 34,355 $ 35,920
Consumers Energy Company          
Segment Reporting Information [Line Items]          
Operating Revenue 1,746 1,533 4,094 3,630  
Power supply cost 537 444 1,083 893  
Cost of gas sold 123 66 505 416  
Maintenance and other operating expenses 376 377 749 755  
Depreciation and amortization 276 261 651 617  
General taxes 106 99 265 251  
Total operating expenses 1,418 1,247 3,253 2,932  
Operating Income 328 286 841 698  
Total other income 60 59 106 115  
Total interest charges 141 126 271 255  
Income (Loss) Before Income Taxes 247 219 676 558  
Income Tax Expense 59 41 142 105  
Net Income 188 178 534 453  
Other segment items (1) (1) (1) (1)  
Net Income (Loss) Available to Common Stockholders 187 177 533 452  
Property, plant, and equipment, gross 34,406 32,224 34,406 32,224 33,434
Total assets 35,467 32,718 35,467 32,718 $ 34,088
Operating Segments          
Segment Reporting Information [Line Items]          
Operating Revenue 1,838 1,607 4,285 3,783  
Power supply cost 603 479 1,218 967  
Operating Income 320 286 816 701  
Total other income 61 61 108 123  
Total interest charges 139 125 269 255  
Income (Loss) Before Income Taxes 242 222 655 569  
Income Tax Expense 36 37 139 111  
Other segment items 8 16 17 40  
Net Income (Loss) Available to Common Stockholders 214 201 533 498  
Total assets 37,435 34,250 37,435 34,250  
Operating Segments | Consumers Energy Company          
Segment Reporting Information [Line Items]          
Operating Revenue 1,746 1,533 4,094 3,630  
Power supply cost 537 444 1,083 893  
Cost of gas sold 123 66 505 416  
Maintenance and other operating expenses 376 377 749 755  
Depreciation and amortization 276 260 651 616  
General taxes 106 99 265 251  
Total operating expenses 1,418 1,246 3,253 2,931  
Operating Income 328 287 841 699  
Total other income 59 59 105 115  
Total interest charges 140 125 270 254  
Income (Loss) Before Income Taxes 247 221 676 560  
Income Tax Expense 54 35 146 108  
Net Income 193 186 530 452  
Other segment items (1) (1) (1) (1)  
Net Income (Loss) Available to Common Stockholders 192 185 529 451  
Property, plant, and equipment, gross 34,370 32,195 34,370 32,195  
Total assets 35,427 32,692 35,427 32,692  
Operating Segments | Electric Utility          
Segment Reporting Information [Line Items]          
Operating Revenue 1,359 1,226 2,658 2,358  
Power supply cost 537 444 1,083 893  
Operating Income 263 244 465 405  
Total other income 36 36 63 70  
Total interest charges 89 79 171 160  
Income (Loss) Before Income Taxes 210 201 357 315  
Income Tax Expense 42 30 65 47  
Other segment items (1) (1) (1) (1)  
Net Income (Loss) Available to Common Stockholders 167 170 291 267  
Total assets 21,942 20,122 21,942 20,122  
Operating Segments | Electric Utility | Consumers Energy Company          
Segment Reporting Information [Line Items]          
Operating Revenue 1,359 1,226 2,658 2,358  
Power supply cost 537 444 1,083 893  
Cost of gas sold 0 0 0 0  
Maintenance and other operating expenses 264 261 521 499  
Depreciation and amortization 222 209 443 422  
General taxes 73 68 146 139  
Total operating expenses 1,096 982 2,193 1,953  
Operating Income 263 244 465 405  
Total other income 36 36 63 70  
Total interest charges 89 79 171 160  
Income (Loss) Before Income Taxes 210 201 357 315  
Income Tax Expense 42 30 65 47  
Net Income 168 171 292 268  
Other segment items (1) (1) (1) (1)  
Net Income (Loss) Available to Common Stockholders 167 170 291 267  
Property, plant, and equipment, gross 20,761 19,557 20,761 19,557  
Total assets 21,997 20,180 21,997 20,180  
Operating Segments | Gas Utility          
Segment Reporting Information [Line Items]          
Operating Revenue 387 307 1,436 1,272  
Power supply cost 0 0 0 0  
Operating Income 65 43 376 294  
Total other income 23 23 42 45  
Total interest charges 51 46 99 94  
Income (Loss) Before Income Taxes 37 20 319 245  
Income Tax Expense 12 5 81 61  
Other segment items 0 0 0 0  
Net Income (Loss) Available to Common Stockholders 25 15 238 184  
Total assets 13,388 12,469 13,388 12,469  
Operating Segments | Gas Utility | Consumers Energy Company          
Segment Reporting Information [Line Items]          
Operating Revenue 387 307 1,436 1,272  
Power supply cost 0 0 0 0  
Cost of gas sold 123 66 505 416  
Maintenance and other operating expenses 112 116 228 256  
Depreciation and amortization 54 51 208 194  
General taxes 33 31 119 112  
Total operating expenses 322 264 1,060 978  
Operating Income 65 43 376 294  
Total other income 23 23 42 45  
Total interest charges 51 46 99 94  
Income (Loss) Before Income Taxes 37 20 319 245  
Income Tax Expense 12 5 81 61  
Net Income 25 15 238 184  
Other segment items 0 0 0 0  
Net Income (Loss) Available to Common Stockholders 25 15 238 184  
Property, plant, and equipment, gross 13,609 12,638 13,609 12,638  
Total assets 13,430 12,512 13,430 12,512  
Other Reconciling Items          
Segment Reporting Information [Line Items]          
Operating Revenue 0 0 0 0  
Power supply cost 0 0 0 0  
Operating Income (3) (3) (5) (6)  
Total other income 76 52 79 76  
Total interest charges 60 48 116 95  
Income (Loss) Before Income Taxes 13 1 (42) (25)  
Income Tax Expense 26 4 (14) (12)  
Other segment items (3) (3) (5) (5)  
Net Income (Loss) Available to Common Stockholders (16) (6) (33) (18)  
Total assets 264 105 264 105  
Other Reconciling Items | Consumers Energy Company          
Segment Reporting Information [Line Items]          
Operating Revenue 0 0 0 0  
Power supply cost 0 0 0 0  
Cost of gas sold 0 0 0 0  
Maintenance and other operating expenses 0 0 0 0  
Depreciation and amortization 0 1 0 1  
General taxes 0 0 0 0  
Total operating expenses 0 1 0 1  
Operating Income 0 (1) 0 (1)  
Total other income 1 0 1 0  
Total interest charges 1 1 1 1  
Income (Loss) Before Income Taxes 0 (2) 0 (2)  
Income Tax Expense 5 6 (4) (3)  
Net Income (5) (8) 4 1  
Other segment items 0 0 0 0  
Net Income (Loss) Available to Common Stockholders (5) (8) 4 1  
Property, plant, and equipment, gross 36 29 36 29  
Total assets $ 40 $ 26 $ 40 $ 26