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Related Parties | 6 Months Ended
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Jun. 30, 2017
Related Party Transactions [Line Items] |
Related Parties | RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. 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 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
ATC LLC - Pursuant to various agreements, WPL receives a range of transmission services from ATC LLC. WPL provides operation, maintenance, and construction services to ATC LLC. WPL and ATC LLC also bill each other for use of shared facilities owned by each party. 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 |
WPL owed ATC LLC net amounts of $8 million as of June 30, 2017 and $8 million as of December 31, 2016. Refer to Note 5(a) for discussion of WPL’s transfer of its investment in ATC LLC to ATI on December 31, 2016. Franklin County Wind Farm - Refer to Note 3 for discussion of the transfer of the Franklin County wind farm from AEF to IPL in April 2017.
IPL [Member] |
Related Party Transactions [Line Items] |
Related Parties | RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. 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 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
ATC LLC - Pursuant to various agreements, WPL receives a range of transmission services from ATC LLC. WPL provides operation, maintenance, and construction services to ATC LLC. WPL and ATC LLC also bill each other for use of shared facilities owned by each party. 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 |
WPL owed ATC LLC net amounts of $8 million as of June 30, 2017 and $8 million as of December 31, 2016. Refer to Note 5(a) for discussion of WPL’s transfer of its investment in ATC LLC to ATI on December 31, 2016. Franklin County Wind Farm - Refer to Note 3 for discussion of the transfer of the Franklin County wind farm from AEF to IPL in April 2017.
WPL [Member] |
Related Party Transactions [Line Items] |
Related Parties | RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. 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 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
ATC LLC - Pursuant to various agreements, WPL receives a range of transmission services from ATC LLC. WPL provides operation, maintenance, and construction services to ATC LLC. WPL and ATC LLC also bill each other for use of shared facilities owned by each party. 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 |
WPL owed ATC LLC net amounts of $8 million as of June 30, 2017 and $8 million as of December 31, 2016. Refer to Note 5(a) for discussion of WPL’s transfer of its investment in ATC LLC to ATI on December 31, 2016.

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- Definition The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(k)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39678-107864 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39691-107864 + Details
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