Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash Flows From Operating Activities:
Net income	$ 235	$ 148
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	295	263
Amortization of nuclear fuel	0	23
Amortization of debt issuance costs and premium/discounts	5	5
Deferred income taxes and investment tax credits, net	26	23
Allowance for equity funds used during construction	(7)	(4)
Stock-based compensation costs	6	6
Other	8	17
Changes in assets and liabilities:
Receivables	(5)	(5)
Inventories	54	23
Accounts and wages payable	(252)	(221)
Taxes accrued	60	47
Regulatory assets and liabilities	(421)	(14)
Assets, other	(9)	(3)
Liabilities, other	(34)	(18)
Pension and other postretirement benefits	4	0
Net cash provided by (used in) operating activities	(35)	290
Cash Flows From Investing Activities:
Capital expenditures	(694)	(636)
Wind generation expenditures	(193)	0
Nuclear fuel expenditures	(1)	(35)
Purchases of securities – nuclear decommissioning trust fund	(152)	(96)
Sales and maturities of securities – nuclear decommissioning trust fund	150	81
Other	1	2
Net cash used in investing activities	(889)	(684)
Cash Flows From Financing Activities:
Dividends on common stock	(140)	(122)
Dividends paid to noncontrolling interest holders	(2)	(2)
Short-term debt, net	399	175
Maturities of long-term debt	0	(85)
Issuances of long-term debt	450	465
Issuances of common stock	125	13
Redemptions of Ameren Illinois preferred stock	(13)	0
Employee payroll taxes related to stock-based compensation	(17)	(20)
Debt issuance costs	(3)	(3)
Other	(4)	0
Net cash provided by financing activities	795	421
Net change in cash, cash equivalents, and restricted cash	(129)	27
Cash, cash equivalents, and restricted cash at beginning of year	301	176
Cash, cash equivalents, and restricted cash at end of period	172	203
Union Electric Company
Cash Flows From Operating Activities:
Net income	48	(9)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	171	148
Amortization of nuclear fuel	0	23
Amortization of debt issuance costs and premium/discounts	1	2
Deferred income taxes and investment tax credits, net	4	(5)
Allowance for equity funds used during construction	(4)	(2)
Other	3	2
Changes in assets and liabilities:
Receivables	20	(3)
Inventories	24	(18)
Accounts and wages payable	(201)	(172)
Taxes accrued	39	55
Regulatory assets and liabilities	(164)	16
Assets, other	13	2
Liabilities, other	(9)	0
Pension and other postretirement benefits	4	2
Net cash provided by (used in) operating activities	(51)	41
Cash Flows From Investing Activities:
Capital expenditures	(341)	(278)
Wind generation expenditures	(193)	0
Nuclear fuel expenditures	(1)	(35)
Purchases of securities – nuclear decommissioning trust fund	(152)	(96)
Sales and maturities of securities – nuclear decommissioning trust fund	150	81
Money pool advances, net	139	0
Net cash used in investing activities	(398)	(328)
Cash Flows From Financing Activities:
Dividends on preferred stock	(1)	(1)
Short-term debt, net	204	(104)
Maturities of long-term debt	0	(85)
Issuances of long-term debt	0	465
Capital contributions from parent	113	0
Debt issuance costs	0	(3)
Net cash provided by financing activities	316	272
Net change in cash, cash equivalents, and restricted cash	(133)	(15)
Cash, cash equivalents, and restricted cash at beginning of year	145	39
Cash, cash equivalents, and restricted cash at end of period	12	24
Ameren Illinois Company
Cash Flows From Operating Activities:
Net income	150	121
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	115	106
Amortization of debt issuance costs and premium/discounts	3	2
Deferred income taxes and investment tax credits, net	53	22
Allowance for equity funds used during construction	(3)	(2)
Other	3	(2)
Changes in assets and liabilities:
Receivables	(24)	(6)
Inventories	30	41
Accounts and wages payable	(40)	(20)
Taxes accrued	3	16
Regulatory assets and liabilities	(255)	(28)
Assets, other	(15)	(4)
Liabilities, other	(9)	(14)
Pension and other postretirement benefits	(1)	(2)
Net cash provided by (used in) operating activities	13	232
Cash Flows From Investing Activities:
Capital expenditures	(337)	(324)
Other	0	1
Net cash used in investing activities	(337)	(323)
Cash Flows From Financing Activities:
Dividends on preferred stock	(1)	(1)
Short-term debt, net	323	7
Money pool borrowings, net	(19)	0
Capital contributions from parent	40	100
Redemption of preferred stock	(13)	0
Other	(4)	0
Net cash provided by financing activities	326	106
Net change in cash, cash equivalents, and restricted cash	2	15
Cash, cash equivalents, and restricted cash at beginning of year	147	125
Cash, cash equivalents, and restricted cash at end of period	$ 149	$ 140