Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flows From Operating Activities:
Net income	$ 153	$ 104
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	230	217
Amortization of nuclear fuel	24	24
Amortization of debt issuance costs and premium/discounts	5	6
Deferred income taxes and investment tax credits, net	26	51
Allowance for equity funds used during construction	(5)	(6)
Stock-based compensation costs	6	4
Other	2	(4)
Changes in assets and liabilities:
Receivables	(26)	44
Inventories	68	60
Accounts and wages payable	(249)	(231)
Taxes accrued	49	36
Regulatory assets and liabilities	20	7
Assets, other	1	7
Liabilities, other	(57)	3
Pension and other postretirement benefits	11	9
Net cash provided by operating activities	258	331
Cash Flows From Investing Activities:
Capital expenditures	(579)	(504)
Nuclear fuel expenditures	(12)	(27)
Purchases of securities - nuclear decommissioning trust fund	(38)	(40)
Sales and maturities of securities - nuclear decommissioning trust fund	34	34
Other	(2)	(2)
Net cash used in investing activities	(597)	(539)
Cash Flows From Financing Activities:
Dividends on common stock	(111)	(107)
Dividends paid to noncontrolling interest holders	(2)	(2)
Short-term debt, net	475	356
Issuance of common stock	17	0
Repurchases of common stock for stock-based compensation	0	(24)
Employee payroll taxes related to stock-based compensation	(19)	(15)
Other	0	(1)
Net cash provided by financing activities	360	207
Net change in cash, cash equivalents, and restricted cash	21	(1)
Cash, cash equivalents, and restricted cash at beginning of year	68	52
Cash, cash equivalents, and restricted cash at end of period	89	51
Noncash financing activity - Issuance of common stock for stock-based compensation	35	0
Union Electric Company
Cash Flows From Operating Activities:
Net income	39	6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	132	127
Amortization of nuclear fuel	24	24
Amortization of debt issuance costs and premium/discounts	2	2
Deferred income taxes and investment tax credits, net	(1)	2
Allowance for equity funds used during construction	(4)	(5)
Other	4	1
Changes in assets and liabilities:
Receivables	4	28
Inventories	5	11
Accounts and wages payable	(192)	(186)
Taxes accrued	36	35
Regulatory assets and liabilities	38	29
Assets, other	(5)	11
Liabilities, other	(10)	4
Pension and other postretirement benefits	4	4
Net cash provided by operating activities	76	93
Cash Flows From Investing Activities:
Capital expenditures	(249)	(196)
Nuclear fuel expenditures	(12)	(27)
Purchases of securities - nuclear decommissioning trust fund	(38)	(40)
Sales and maturities of securities - nuclear decommissioning trust fund	34	34
Money pool advances, net	0	161
Other	0	0
Net cash used in investing activities	(265)	(68)
Cash Flows From Financing Activities:
Dividends on common stock	(50)	(60)
Dividends on preferred stock	(1)	(1)
Short-term debt, net	243	36
Net cash provided by financing activities	192	(25)
Net change in cash, cash equivalents, and restricted cash	3	0
Cash, cash equivalents, and restricted cash at beginning of year	7	5
Cash, cash equivalents, and restricted cash at end of period	10	5
Ameren Illinois Company
Cash Flows From Operating Activities:
Net income	96	80
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	90	83
Amortization of debt issuance costs and premium/discounts	3	3
Deferred income taxes and investment tax credits, net	9	51
Allowance for equity funds used during construction	(1)	(1)
Other	(2)	0
Changes in assets and liabilities:
Receivables	(34)	16
Inventories	63	49
Accounts and wages payable	(52)	(51)
Taxes accrued	1	(2)
Regulatory assets and liabilities	(16)	(19)
Assets, other	2	2
Liabilities, other	(36)	(5)
Pension and other postretirement benefits	6	5
Net cash provided by operating activities	130	212
Cash Flows From Investing Activities:
Capital expenditures	(300)	(227)
Net cash used in investing activities	(300)	(227)
Cash Flows From Financing Activities:
Dividends on preferred stock	(1)	(1)
Short-term debt, net	162	17
Capital contribution from parent	20
Other	0	(1)
Net cash provided by financing activities	181	15
Net change in cash, cash equivalents, and restricted cash	11	0
Cash, cash equivalents, and restricted cash at beginning of year	41	28
Cash, cash equivalents, and restricted cash at end of period	$ 52	$ 28