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Commitments And Contingencies (Narrative) (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2015 USD ($) site
Long-term Purchase Commitment [Line Items] |  |
Minimum future commitments | $ 2,292 |
Time frame for plaintiffs to seek appeal of decision | 30 days |
Performance guarantees outstanding | $ 123 |
Present value abandonment obligation | $ 28 |
Minimum [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Warranty period | 12 months |
Maximum [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Warranty period | 60 months |
Performance guarantees outstanding, 2016 [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Performance guarantees outstanding | $ 48 |
Performance guarantees outstanding, 2017 [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Performance guarantees outstanding | 75 |
Capital Purchase Obligation [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Minimum future commitments | 23 |
DAEC IPL [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Minimum future commitments | 1,419 | [1],[2]
IPL [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Minimum future commitments | 1,792 |
Maximum indemnification limit | $ 17 |
Number of sites monitoring and/or remediating (in sites) | site | 24 |
IPL [Member] | Capital Purchase Obligation [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Minimum future commitments | $ 7 |
WPL [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Minimum future commitments | $ 482 |
Number of sites monitoring and/or remediating (in sites) | site | 5 |
WPL [Member] | Capital Purchase Obligation [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Minimum future commitments | $ 16 |
Environmental Issue [Member] | IPL [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Damages awarded | 6 |
Environmental Issue [Member] | WPL [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Damages awarded | 7 |
Civil Penalty [Member] | IPL [Member] |  |
Long-term Purchase Commitment [Line Items] |  |
Damages awarded | $ 1 |
[1] | Includes commitments incurred under a PPA, which grants IPL rights to purchase up to 431 MWs of capacity and the resulting energy from DAEC for a term through December 31, 2025. If energy delivered is less than the targeted energy amount, an adjustment payment will be made to IPL, which will be reflected in IPL’s fuel adjustment clause.
[2] | Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased. Refer to Note 18 for additional information on purchased power transactions.

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