| Three Months Ended March 31, | |||||||||||
| 2025 | 2024 | ||||||||||
| Operating Revenues: | |||||||||||
| Electric | $ | 1,622 | $ | 1,364 | |||||||
| Natural gas | 475 | 452 | |||||||||
| Total operating revenues | 2,097 | 1,816 | |||||||||
| Operating Expenses: | |||||||||||
| Fuel and purchased power | 502 | 328 | |||||||||
| Natural gas purchased for resale | 169 | 151 | |||||||||
| Other operations and maintenance | 485 | 470 | |||||||||
| Depreciation and amortization | 367 | 361 | |||||||||
| Taxes other than income taxes | 144 | 135 | |||||||||
| Total operating expenses | 1,667 | 1,445 | |||||||||
| Operating Income | 430 | 371 | |||||||||
| Other Income, Net | 85 | 89 | |||||||||
| Interest Charges | 175 | 154 | |||||||||
| Income Before Income Taxes | 340 | 306 | |||||||||
| Income Taxes | 50 | 44 | |||||||||
| Net Income | 290 | 262 | |||||||||
| Less: Net Income Attributable to Noncontrolling Interests | 1 | 1 | |||||||||
| Net Income Attributable to Ameren Common Shareholders | $ | 289 | $ | 261 | |||||||
| Earnings per Common Share - Basic and Diluted | $ | 1.07 | $ | 0.98 | |||||||
| Weighted-average Common Shares Outstanding – Basic | 270.0 | 266.4 | |||||||||
| Weighted-average Common Shares Outstanding – Diluted | 271.4 | 266.8 | |||||||||
| March 31, 2025 | December 31, 2024 | ||||||||||
| ASSETS | |||||||||||
| Current Assets: | |||||||||||
| Cash and cash equivalents | $ | 23 | $ | 7 | |||||||
| Accounts receivable - trade (less allowance for doubtful accounts) | 667 | 525 | |||||||||
| Unbilled revenue | 253 | 346 | |||||||||
| Miscellaneous accounts receivable | 327 | 96 | |||||||||
| Inventories | 669 | 762 | |||||||||
| Current regulatory assets | 340 | 366 | |||||||||
| Other current assets | 176 | 162 | |||||||||
| Total current assets | 2,455 | 2,264 | |||||||||
| Property, Plant, and Equipment, Net | 37,010 | 36,304 | |||||||||
| Investments and Other Assets: | |||||||||||
| Nuclear decommissioning trust fund | 1,312 | 1,342 | |||||||||
| Goodwill | 411 | 411 | |||||||||
| Regulatory assets | 2,569 | 2,397 | |||||||||
| Pension and other postretirement benefits | 765 | 757 | |||||||||
| Other assets | 1,143 | 1,123 | |||||||||
| Total investments and other assets | 6,200 | 6,030 | |||||||||
| TOTAL ASSETS | $ | 45,665 | $ | 44,598 | |||||||
| LIABILITIES AND EQUITY | |||||||||||
| Current Liabilities: | |||||||||||
| Current maturities of long-term debt | $ | 17 | $ | 317 | |||||||
| Short-term debt | 1,252 | 1,143 | |||||||||
| Accounts and wages payable | 702 | 1,059 | |||||||||
| Interest accrued | 159 | 196 | |||||||||
| Customer deposits | 223 | 223 | |||||||||
| Other current liabilities | 510 | 475 | |||||||||
| Total current liabilities | 2,863 | 3,413 | |||||||||
| Long-term Debt, Net | 18,354 | 17,262 | |||||||||
| Deferred Credits and Other Liabilities: | |||||||||||
| Accumulated deferred income taxes and tax credits, net | 4,782 | 4,474 | |||||||||
| Regulatory liabilities | 5,953 | 5,897 | |||||||||
| Asset retirement obligations | 830 | 822 | |||||||||
| Other deferred credits and liabilities | 535 | 487 | |||||||||
| Total deferred credits and other liabilities | 12,100 | 11,680 | |||||||||
| Shareholders’ Equity: | |||||||||||
| Common stock | 3 | 3 | |||||||||
| Other paid-in capital, principally premium on common stock | 7,524 | 7,513 | |||||||||
| Retained earnings | 4,702 | 4,604 | |||||||||
| Accumulated other comprehensive loss | (10) | (6) | |||||||||
| Total shareholders’ equity | 12,219 | 12,114 | |||||||||
| Noncontrolling Interests | 129 | 129 | |||||||||
| Total equity | 12,348 | 12,243 | |||||||||
| TOTAL LIABILITIES AND EQUITY | $ | 45,665 | $ | 44,598 | |||||||
| Three Months Ended March 31, | |||||||||||
| 2025 | 2024 | ||||||||||
| Cash Flows From Operating Activities: | |||||||||||
| Net income | $ | 290 | $ | 262 | |||||||
| Adjustments to reconcile net income to net cash provided by operating activities: | |||||||||||
| Depreciation and amortization | 395 | 379 | |||||||||
| Amortization of nuclear fuel | 20 | 18 | |||||||||
| Amortization of debt issuance costs and premium/discounts | 5 | 5 | |||||||||
| Deferred income taxes and tax credits, net | 116 | 44 | |||||||||
| Allowance for equity funds used during construction | (16) | (9) | |||||||||
| Stock-based compensation costs | 7 | 8 | |||||||||
| Other | 7 | 16 | |||||||||
| Changes in assets and liabilities | (393) | (231) | |||||||||
| Net cash provided by operating activities | 431 | 492 | |||||||||
| Cash Flows From Investing Activities: | |||||||||||
| Capital expenditures | (1,064) | (890) | |||||||||
| Nuclear fuel expenditures | (18) | (12) | |||||||||
| Purchases of securities – nuclear decommissioning trust fund | (107) | (70) | |||||||||
| Sales and maturities of securities – nuclear decommissioning trust fund | 93 | 66 | |||||||||
| Other | 9 | — | |||||||||
| Net cash used in investing activities | (1,087) | (906) | |||||||||
| Cash Flows From Financing Activities: | |||||||||||
| Dividends on common stock | (191) | (178) | |||||||||
| Dividends paid to noncontrolling interest holders | (1) | (1) | |||||||||
| Short-term debt, net | 108 | 332 | |||||||||
| Maturities of long-term debt | (300) | — | |||||||||
| Issuances of long-term debt | 1,099 | 347 | |||||||||
| Issuances of common stock | 13 | 10 | |||||||||
| Employee payroll taxes related to stock-based compensation | (13) | (8) | |||||||||
| Debt issuance costs | (11) | (5) | |||||||||
| Net cash provided by financing activities | 704 | 497 | |||||||||
| Net change in cash, cash equivalents, and restricted cash | 48 | 83 | |||||||||
Cash, cash equivalents, and restricted cash at beginning of year(a) | 328 | 272 | |||||||||
Cash, cash equivalents, and restricted cash at end of period(b) | $ | 376 | $ | 355 | |||||||