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Related Parties (Tables) | 9 Months Ended
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Sep. 30, 2019
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 nine months ended September 30 were as follows (in millions):
| IPL |  | WPL
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
| 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018
Corporate Services billings |  | $47 |  |  |  | $43 |  |  |  | $137 |  |  |  | $128 |  |  |  | $36 |  |  |  | $33 |  |  |  | $104 |  |  |  | $100 |
Sales credited | 23 |  |  | 11 |  |  | 50 |  |  | 34 |  |  | 2 |  |  | 7 |  |  | 6 |  |  | 16 |
Purchases billed | 93 |  |  | 95 |  |  | 251 |  |  | 268 |  |  | 32 |  |  | 19 |  |  | 91 |  |  | 56 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions):
| IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Net payables to Corporate Services | $108 |  | $95 |  | $75 |  | $71
Related Amounts Billed Between Parties | The related amounts billed between the parties for the three and nine months ended September 30 were as follows (in millions):
| Three Months |  | Nine Months
| 2019 |  | 2018 |  | 2019 |  | 2018
ATC billings to WPL |  | $28 |  |  |  | $26 |  |  |  | $82 |  |  |  | $79 |
WPL billings to ATC | 3 |  |  | 3 |  |  | 10 |  |  | 8 |
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 nine months ended September 30 were as follows (in millions):
| IPL |  | WPL
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
| 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018
Corporate Services billings |  | $47 |  |  |  | $43 |  |  |  | $137 |  |  |  | $128 |  |  |  | $36 |  |  |  | $33 |  |  |  | $104 |  |  |  | $100 |
Sales credited | 23 |  |  | 11 |  |  | 50 |  |  | 34 |  |  | 2 |  |  | 7 |  |  | 6 |  |  | 16 |
Purchases billed | 93 |  |  | 95 |  |  | 251 |  |  | 268 |  |  | 32 |  |  | 19 |  |  | 91 |  |  | 56 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions):
| IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Net payables to Corporate Services | $108 |  | $95 |  | $75 |  | $71
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 nine months ended September 30 were as follows (in millions):
| IPL |  | WPL
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
| 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018 |  | 2019 |  | 2018
Corporate Services billings |  | $47 |  |  |  | $43 |  |  |  | $137 |  |  |  | $128 |  |  |  | $36 |  |  |  | $33 |  |  |  | $104 |  |  |  | $100 |
Sales credited | 23 |  |  | 11 |  |  | 50 |  |  | 34 |  |  | 2 |  |  | 7 |  |  | 6 |  |  | 16 |
Purchases billed | 93 |  |  | 95 |  |  | 251 |  |  | 268 |  |  | 32 |  |  | 19 |  |  | 91 |  |  | 56 |
Net Intercompany Payables | Net intercompany payables to Corporate Services were as follows (in millions):
| IPL |  | WPL
| September 30, 2019 |  | December 31, 2018 |  | September 30, 2019 |  | December 31, 2018
Net payables to Corporate Services | $108 |  | $95 |  | $75 |  | $71
Related Amounts Billed Between Parties | The related amounts billed between the parties for the three and nine months ended September 30 were as follows (in millions):
| Three Months |  | Nine Months
| 2019 |  | 2018 |  | 2019 |  | 2018
ATC billings to WPL |  | $28 |  |  |  | $26 |  |  |  | $82 |  |  |  | $79 |
WPL billings to ATC | 3 |  |  | 3 |  |  | 10 |  |  | 8 |

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