Consolidated Statement Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Flows From Operating Activities:
Net income	$ 1,187	$ 1,157	$ 1,079
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,524	1,432	1,373
Amortization of nuclear fuel	81	68	65
Amortization of debt issuance costs and premium/discounts	19	16	21
Deferred income taxes and production and investment tax credits, net	127	229	170
Allowance for equity funds used during construction	76	54	43
Stock-based compensation costs	28	26	24
Other	87	16	68
Changes in assets and liabilities:
Receivables	(91)	144	(317)
Inventories	(31)	(67)	(77)
Accounts and wages payable	4	(104)	136
Taxes accrued	34	(4)	(13)
Regulatory assets and liabilities	99	(165)	(72)
Assets, other	(34)	(109)	(74)
Liabilities, other	22	115	52
Pension and other postretirement benefits	(216)	(283)	(65)
Counterparty collateral, net	(1)	147	(64)
Net cash provided by operating activities	2,763	2,564	2,263
Cash Flows From Investing Activities:
Capital expenditures	(4,319)	(3,597)	(3,351)
Nuclear fuel expenditures	(91)	(174)	(29)
Purchases of securities – nuclear decommissioning trust fund	(584)	(266)	(229)
Proceeds from sales and maturities	564	240	216
Other	(26)	(1)	23
Net cash used in investing activities	(4,456)	(3,798)	(3,370)
Cash Flows From Financing Activities:
Dividends on common stock	(714)	(662)	(610)
Dividends paid to noncontrolling interest holders	(5)	(5)	(5)
Short-term debt, net	607	(533)	522
Maturities and extinguishment of long-term debt	(893)	(100)	(505)
Issuances of long-term debt	2,535	2,295	1,467
Issuances of common stock	273	346	333
Employee payroll taxes related to stock-based compensation	(8)	(20)	(16)
Debt issuance costs	(31)	(21)	(18)
Other	(15)	(10)	0
Net cash provided by financing activities	1,749	1,290	1,168
Net change in cash, cash equivalents, and restricted cash	56	56	61
Cash, cash equivalents, and restricted cash at beginning of year	272	216	155
Cash Paid (Refunded) During the Year:
Interest (net of amounts capitalized, respectively)	611	546	476
Income Taxes Paid, Net	(92)	(24)	(8)
Ameren Missouri
Cash Flows From Operating Activities:
Net Income Attributable to Ameren Common Shareholders	562	548	565
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	851	827	816
Amortization of nuclear fuel	81	68	65
Amortization of debt issuance costs and premium/discounts	7	7	7
Deferred income taxes and production and investment tax credits, net	(29)	28	21
Allowance for equity funds used during construction	58	30	24
Other	74	(8)	14
Changes in assets and liabilities:
Receivables	(26)	39	(68)
Inventories	(6)	(74)	(15)
Accounts and wages payable	17	(8)	19
Taxes accrued	60	(17)	(21)
Regulatory assets and liabilities	51	(7)	(206)
Assets, other	0	(25)	1
Liabilities, other	18	3	7
Pension and other postretirement benefits	(76)	(106)	(16)
Counterparty collateral, net	(3)	96	(35)
Net cash provided by operating activities	1,523	1,341	1,130
Cash Flows From Investing Activities:
Capital expenditures	(2,712)	(1,760)	(1,690)
Nuclear fuel expenditures	(91)	(174)	(29)
Purchases of securities – nuclear decommissioning trust fund	(584)	(266)	(229)
Proceeds from sales and maturities	564	240	216
Money pool advances, net	(43)	0	0
Other	(32)	0	29
Net cash used in investing activities	(2,898)	(1,960)	(1,703)
Cash Flows From Financing Activities:
Dividends on common stock	0	(9)	(46)
Dividends on preferred stock	(3)	(3)	(3)
Short-term debt, net	(170)	(159)	164
Money pool borrowings, net	(306)	306	0
Maturities and extinguishment of long-term debt	(350)	0	(55)
Issuances of long-term debt	1,771	499	524
Debt issuance costs	(21)	(8)	(6)
Capital contribution from parent	476	0	0
Other	(15)	(10)	0
Net cash provided by financing activities	1,382	616	578
Net change in cash, cash equivalents, and restricted cash	7	(3)	5
Cash, cash equivalents, and restricted cash at beginning of year	10	13	8
Cash Paid (Refunded) During the Year:
Interest (net of amounts capitalized, respectively)	244	225	230
Income Taxes Paid, Net	(136)	(19)	(20)
Ameren Illinois
Cash Flows From Operating Activities:
Net Income Attributable to Ameren Common Shareholders	622	609	515
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	619	557	514
Amortization of debt issuance costs and premium/discounts	6	5	11
Deferred income taxes and production and investment tax credits, net	188	177	117
Allowance for equity funds used during construction	17	19	18
Other	41	40	29
Changes in assets and liabilities:
Receivables	(70)	129	(250)
Inventories	(21)	7	(62)
Accounts and wages payable	1	(107)	117
Taxes accrued	55	(73)	34
Regulatory assets and liabilities	53	(152)	134
Assets, other	(33)	(123)	(67)
Liabilities, other	2	106	42
Pension and other postretirement benefits	(88)	(112)	(39)
Counterparty collateral, net	11	54	(29)
Net cash provided by operating activities	1,369	1,098	1,048
Cash Flows From Investing Activities:
Capital expenditures	(1,467)	(1,731)	(1,601)
Other	1	(2)	(1)
Net cash used in investing activities	(1,466)	(1,733)	(1,602)
Cash Flows From Financing Activities:
Dividends on common stock	(110)	(41)	0
Dividends on preferred stock	(2)	(2)	(2)
Short-term debt, net	(277)	102	161
Money pool borrowings, net	(98)	135	0
Maturities and extinguishment of long-term debt	0	(100)	(400)
Issuances of long-term debt	624	498	848
Debt issuance costs	(8)	(5)	(10)
Capital contribution from parent	36	91	15
Net cash provided by financing activities	165	678	612
Net change in cash, cash equivalents, and restricted cash	68	43	58
Cash, cash equivalents, and restricted cash at beginning of year	234	191	133
Cash Paid (Refunded) During the Year:
Interest (net of amounts capitalized, respectively)	213	195	152
Income Taxes Paid, Net	$ (46)	$ 102	$ 23