| Three Months Ended June 30, | Six Months Ended June 30, | ||||||||||||||||||||||
| 2023 | 2022 | 2023 | 2022 | ||||||||||||||||||||
| Operating Revenues: | |||||||||||||||||||||||
| Electric | $ | 1,585 | $ | 1,513 | $ | 3,175 | $ | 2,831 | |||||||||||||||
| Natural gas | 175 | 213 | 647 | 774 | |||||||||||||||||||
| Total operating revenues | 1,760 | 1,726 | 3,822 | 3,605 | |||||||||||||||||||
| Operating Expenses: | |||||||||||||||||||||||
| Fuel | 152 | 83 | 265 | 259 | |||||||||||||||||||
| Purchased power | 328 | 318 | 823 | 495 | |||||||||||||||||||
| Natural gas purchased for resale | 42 | 80 | 250 | 373 | |||||||||||||||||||
| Other operations and maintenance | 450 | 491 | 898 | 952 | |||||||||||||||||||
| Depreciation and amortization | 335 | 316 | 655 | 615 | |||||||||||||||||||
| Taxes other than income taxes | 124 | 129 | 251 | 271 | |||||||||||||||||||
| Total operating expenses | 1,431 | 1,417 | 3,142 | 2,965 | |||||||||||||||||||
| Operating Income | 329 | 309 | 680 | 640 | |||||||||||||||||||
| Other Income, Net | 82 | 62 | 160 | 122 | |||||||||||||||||||
| Interest Charges | 134 | 126 | 261 | 230 | |||||||||||||||||||
| Income Before Income Taxes | 277 | 245 | 579 | 532 | |||||||||||||||||||
| Income Taxes | 38 | 36 | 75 | 70 | |||||||||||||||||||
| Net Income | 239 | 209 | 504 | 462 | |||||||||||||||||||
| Less: Net Income Attributable to Noncontrolling Interests | 2 | 2 | 3 | 3 | |||||||||||||||||||
| Net Income Attributable to Ameren Common Shareholders | $ | 237 | $ | 207 | $ | 501 | $ | 459 | |||||||||||||||
| Earnings per Common Share – Basic | $ | 0.90 | $ | 0.80 | $ | 1.91 | $ | 1.78 | |||||||||||||||
| Earnings per Common Share – Diluted | $ | 0.90 | $ | 0.80 | $ | 1.90 | $ | 1.77 | |||||||||||||||
| Weighted-average Common Shares Outstanding – Basic | 262.6 | 258.2 | 262.4 | 258.0 | |||||||||||||||||||
| Weighted-average Common Shares Outstanding – Diluted | 263.2 | 259.4 | 263.2 | 259.2 | |||||||||||||||||||
| June 30, 2023 | December 31, 2022 | ||||||||||
| ASSETS | |||||||||||
| Current Assets: | |||||||||||
| Cash and cash equivalents | $ | 7 | $ | 10 | |||||||
| Accounts receivable - trade (less allowance for doubtful accounts) | 482 | 600 | |||||||||
| Unbilled revenue | 378 | 446 | |||||||||
| Miscellaneous accounts receivable | 63 | 54 | |||||||||
| Inventories | 711 | 667 | |||||||||
| Current regulatory assets | 239 | 354 | |||||||||
| Investment in industrial development revenue bonds | — | 240 | |||||||||
| Current collateral assets | 20 | 142 | |||||||||
| Other current assets | 119 | 155 | |||||||||
| Total current assets | 2,019 | 2,668 | |||||||||
| Property, Plant, and Equipment, Net | 32,351 | 31,262 | |||||||||
| Investments and Other Assets: | |||||||||||
| Nuclear decommissioning trust fund | 1,075 | 958 | |||||||||
| Goodwill | 411 | 411 | |||||||||
| Regulatory assets | 1,790 | 1,426 | |||||||||
| Pension and other postretirement benefits | 442 | 411 | |||||||||
| Other assets | 859 | 768 | |||||||||
| Total investments and other assets | 4,577 | 3,974 | |||||||||
| TOTAL ASSETS | $ | 38,947 | $ | 37,904 | |||||||
| LIABILITIES AND EQUITY | |||||||||||
| Current Liabilities: | |||||||||||
| Current maturities of long-term debt | $ | 350 | $ | 340 | |||||||
| Short-term debt | 1,329 | 1,070 | |||||||||
| Accounts and wages payable | 719 | 1,159 | |||||||||
| Other current liabilities | 845 | 797 | |||||||||
| Total current liabilities | 3,243 | 3,366 | |||||||||
| Long-term Debt, Net | 14,328 | 13,685 | |||||||||
| Deferred Credits and Other Liabilities: | |||||||||||
| Accumulated deferred income taxes and tax credits, net | 3,913 | 3,804 | |||||||||
| Regulatory liabilities | 5,445 | 5,309 | |||||||||
| Asset retirement obligations | 775 | 763 | |||||||||
| Other deferred credits and liabilities | 417 | 340 | |||||||||
| Total deferred credits and other liabilities | 10,550 | 10,216 | |||||||||
| Shareholders’ Equity: | |||||||||||
| Common stock | 3 | 3 | |||||||||
| Other paid-in capital, principally premium on common stock | 6,880 | 6,860 | |||||||||
| Retained earnings | 3,817 | 3,646 | |||||||||
| Accumulated other comprehensive loss | (3) | (1) | |||||||||
| Total shareholders’ equity | 10,697 | 10,508 | |||||||||
| Noncontrolling Interests | 129 | 129 | |||||||||
| Total equity | 10,826 | 10,637 | |||||||||
| TOTAL LIABILITIES AND EQUITY | $ | 38,947 | $ | 37,904 | |||||||
| Six Months Ended June 30, | |||||||||||
| 2023 | 2022 | ||||||||||
| Cash Flows From Operating Activities: | |||||||||||
| Net income | $ | 504 | $ | 462 | |||||||
| Adjustments to reconcile net income to net cash provided by operating activities: | |||||||||||
| Depreciation and amortization | 703 | 665 | |||||||||
| Amortization of nuclear fuel | 36 | 28 | |||||||||
| Amortization of debt issuance costs and premium/discounts | 8 | 12 | |||||||||
| Deferred income taxes and investment tax credits, net | 66 | 66 | |||||||||
| Allowance for equity funds used during construction | (23) | (19) | |||||||||
| Stock-based compensation costs | 14 | 12 | |||||||||
| Other | (19) | 33 | |||||||||
| Changes in assets and liabilities | (178) | (387) | |||||||||
| Net cash provided by operating activities | 1,111 | 872 | |||||||||
| Cash Flows From Investing Activities: | |||||||||||
| Capital expenditures | (1,822) | (1,538) | |||||||||
| Nuclear fuel expenditures | (50) | (22) | |||||||||
| Purchases of securities – nuclear decommissioning trust fund | (81) | (122) | |||||||||
| Sales and maturities of securities – nuclear decommissioning trust fund | 65 | 114 | |||||||||
| Other | (1) | 16 | |||||||||
| Net cash used in investing activities | (1,889) | (1,552) | |||||||||
| Cash Flows From Financing Activities: | |||||||||||
| Dividends on common stock | (330) | (305) | |||||||||
| Dividends paid to noncontrolling interest holders | (3) | (3) | |||||||||
| Short-term debt, net | 260 | 475 | |||||||||
| Maturities of long-term debt | (100) | — | |||||||||
| Issuances of long-term debt | 997 | 524 | |||||||||
| Issuances of common stock | 16 | 17 | |||||||||
| Employee payroll taxes related to stock-based compensation | (20) | (16) | |||||||||
| Debt issuance costs | (9) | (6) | |||||||||
| Other | (3) | — | |||||||||
| Net cash provided by financing activities | 808 | 686 | |||||||||
| Net change in cash, cash equivalents, and restricted cash | 30 | 6 | |||||||||
| Cash, cash equivalents, and restricted cash at beginning of year | 216 | 155 | |||||||||
| Cash, cash equivalents, and restricted cash at end of period | $ | 246 | $ | 161 | |||||||