Schedule I - Condensed Financial Information Of Parent (Statement of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 1,551	$ 1,693	$ 1,690
Cash Flows From Investing Activities:
Proceeds from Collection of Notes Receivable	95	6
Contributions to Note Receivable	(89)aee_ContributionstoNoteReceivable	(5)aee_ContributionstoNoteReceivable
Other	11	1	20
Net Cash Provided by (Used in) Investing Activities	(1,717)	(1,723)	(1,310)
Cash flows from financing activities:
Dividends on common stock	(390)us-gaap_PaymentsOfDividendsCommonStock	(388)us-gaap_PaymentsOfDividendsCommonStock	(382)us-gaap_PaymentsOfDividendsCommonStock
Short-term debt and credit facility borrowings, net	346	368	(148)
Repayments of Other Long-term Debt	(697)us-gaap_RepaymentsOfOtherLongTermDebt	(399)us-gaap_RepaymentsOfOtherLongTermDebt	(760)us-gaap_RepaymentsOfOtherLongTermDebt
Net cash provided by (used in) financing activities	141	(149)	(426)
Net change in cash and cash equivalents	(25)	(179)	(46)
Cash and cash equivalents at beginning of year	30	184
Cash and cash equivalents at end of year	5	30	184
Noncash financing activity – dividends on common stock			7
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	514	453	532
Cash Flows From Investing Activities:
Money pool advances, net	279	(371)	24
Intercompany notes receivable, net	(134)	(23)	(20)
Investments in subsidiaries	(280)	(50)	(2)
Return of investments	215	1	21
Proceeds from Collection of Notes Receivable	95	6	0
Contributions to Note Receivable	(89)	(5)	0
Other	(12)	(3)	(5)
Net Cash Provided by (Used in) Investing Activities	74	(445)	18
Cash flows from financing activities:
Dividends on common stock	(390)	(388)	(382)
Short-term debt and credit facility borrowings, net	217	368	(148)
Repayments of Other Long-term Debt	(425)	0	0
Net cash provided by (used in) financing activities	(598)	(20)	(530)
Net change in cash and cash equivalents	(10)	(12)	20
Cash and cash equivalents at beginning of year	11	23	3
Cash and cash equivalents at end of year	1	11	23
Cash dividends received from consolidated subsidiaries	340	570	610
Noncash investing activity - divestiture		494	0
Noncash Investing activity- investment in subsidiaries	(19)	0	0
Noncash financing activity – dividends on common stock			$ (7)

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes.

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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

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Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity).

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