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Receivables (Maximum And Average Outstanding Cash Proceeds) (Details) - IPL [Member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Outstanding aggregate cash proceeds (based on daily outstanding balances) | $ 180.0 | $ 180.0 | $ 180.0
Maximum [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Outstanding aggregate cash proceeds (based on daily outstanding balances) | 172.0 | 137.0 | 150.0
Average [Member] |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Outstanding aggregate cash proceeds (based on daily outstanding balances) | $ 73.2 | $ 46.7 | $ 46.4

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- Definition The cash inflow associated with the proceeds from sale and collection of receivables during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585 + Details
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