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Related Parties (Tables) | 6 Months Ended
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Jun. 30, 2017
Related Party Transactions [Line Items] |
Services Provided, Sales Credited And Purchases | The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions):
| IPL |  | WPL
| Three Months |  | Six Months |  | Three Months |  | Six Months
| 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016
Corporate Services billings |  | $43 |  |  |  | $45 |  |  |  | $82 |  |  |  | $83 |  |  |  | $32 |  |  |  | $37 |  |  |  | $63 |  |  |  | $70 |
Sales credited | 5 |  |  | 2 |  |  | 7 |  |  | 3 |  |  | 2 |  |  | 2 |  |  | 2 |  |  | 3 |
Purchases billed | 96 |  |  | 102 |  |  | 162 |  |  | 198 |  |  | 33 |  |  | 23 |  |  | 67 |  |  | 42 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions):
| IPL |  | WPL
| June 30, 2017 |  | December 31, 2016 |  | June 30, 2017 |  | December 31, 2016
Net payables to Corporate Services | $102 |  | $104 |  | $69 |  | $72
Related Amounts Billed Between Parties | The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions):
| Three Months |  | Six Months
| 2017 |  | 2016 |  | 2017 |  | 2016
ATC LLC billings to WPL |  | $27 |  |  |  | $27 |  |  |  | $53 |  |  |  | $54 |
WPL billings to ATC LLC | 3 |  |  | 3 |  |  | 6 |  |  | 6 |
IPL [Member] |
Related Party Transactions [Line Items] |
Services Provided, Sales Credited And Purchases | The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions):
| IPL |  | WPL
| Three Months |  | Six Months |  | Three Months |  | Six Months
| 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016
Corporate Services billings |  | $43 |  |  |  | $45 |  |  |  | $82 |  |  |  | $83 |  |  |  | $32 |  |  |  | $37 |  |  |  | $63 |  |  |  | $70 |
Sales credited | 5 |  |  | 2 |  |  | 7 |  |  | 3 |  |  | 2 |  |  | 2 |  |  | 2 |  |  | 3 |
Purchases billed | 96 |  |  | 102 |  |  | 162 |  |  | 198 |  |  | 33 |  |  | 23 |  |  | 67 |  |  | 42 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions):
| IPL |  | WPL
| June 30, 2017 |  | December 31, 2016 |  | June 30, 2017 |  | December 31, 2016
Net payables to Corporate Services | $102 |  | $104 |  | $69 |  | $72
WPL [Member] |
Related Party Transactions [Line Items] |
Services Provided, Sales Credited And Purchases | The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions):
| IPL |  | WPL
| Three Months |  | Six Months |  | Three Months |  | Six Months
| 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016 |  | 2017 |  | 2016
Corporate Services billings |  | $43 |  |  |  | $45 |  |  |  | $82 |  |  |  | $83 |  |  |  | $32 |  |  |  | $37 |  |  |  | $63 |  |  |  | $70 |
Sales credited | 5 |  |  | 2 |  |  | 7 |  |  | 3 |  |  | 2 |  |  | 2 |  |  | 2 |  |  | 3 |
Purchases billed | 96 |  |  | 102 |  |  | 162 |  |  | 198 |  |  | 33 |  |  | 23 |  |  | 67 |  |  | 42 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions):
| IPL |  | WPL
| June 30, 2017 |  | December 31, 2016 |  | June 30, 2017 |  | December 31, 2016
Net payables to Corporate Services | $102 |  | $104 |  | $69 |  | $72
Related Amounts Billed Between Parties | The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions):
| Three Months |  | Six Months
| 2017 |  | 2016 |  | 2017 |  | 2016
ATC LLC billings to WPL |  | $27 |  |  |  | $27 |  |  |  | $53 |  |  |  | $54 |
WPL billings to ATC LLC | 3 |  |  | 3 |  |  | 6 |  |  | 6 |

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