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Related Parties | 12 Months Ended
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Dec. 31, 2016
Related Party Transaction [Line Items] |
Related Parties | RELATED PARTIES Service Agreements - IPL and WPL are parties to service agreements with an affiliate, Corporate Services. Pursuant to these service agreements, IPL and WPL receive various administrative and general 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 were as follows (in millions):
| IPL |  | WPL
| 2016 |  | 2015 |  | 2014 |  | 2016 |  | 2015 |  | 2014
Corporate Services billings |  | $161 |  |  |  | $150 |  |  |  | $148 |  |  |  | $133 |  |  |  | $121 |  |  |  | $116 |
Sales credited | 8 |  |  | 10 |  | 8 |  | 7 |  |  | 24 |  | 6
Purchases billed | 433 |  |  | 366 |  | 422 |  | 102 |  |  | 66 |  | 125
As of December 31, net intercompany payables to Corporate Services were as follows (in millions):
| 2016 |  | 2015
IPL |  | $104 |  |  |  | $93 |
WPL | 72 |  |  | 54 |
ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties were as follows (in millions):
| 2016 |  | 2015 |  | 2014
ATC billings to WPL |  | $110 |  |  |  | $101 |  |  |  | $96 |
WPL billings to ATC | 13 |  |  | 13 |  |  | 9 |
As of December 31, 2016 and 2015, WPL owed ATC net amounts of $8 million and $8 million, respectively. Refer to Note 6(a) for discussion of WPL’s transfer of its investment in ATC to ATI on December 31, 2016. WPL’s Sheboygan Falls Lease - Refer to Note 10(b) for discussion of WPL’s Sheboygan Falls lease. Franklin County Wind Farm - Refer to Note 3 for discussion of a February 2017 FERC order approving the transfer of the Franklin County wind farm from AEF to IPL. Alliant Energy and IPL currently expect to complete this transfer in 2017.
IPL [Member] |
Related Party Transaction [Line Items] |
Related Parties | RELATED PARTIES Service Agreements - IPL and WPL are parties to service agreements with an affiliate, Corporate Services. Pursuant to these service agreements, IPL and WPL receive various administrative and general 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 were as follows (in millions):
| IPL |  | WPL
| 2016 |  | 2015 |  | 2014 |  | 2016 |  | 2015 |  | 2014
Corporate Services billings |  | $161 |  |  |  | $150 |  |  |  | $148 |  |  |  | $133 |  |  |  | $121 |  |  |  | $116 |
Sales credited | 8 |  |  | 10 |  | 8 |  | 7 |  |  | 24 |  | 6
Purchases billed | 433 |  |  | 366 |  | 422 |  | 102 |  |  | 66 |  | 125
As of December 31, net intercompany payables to Corporate Services were as follows (in millions):
| 2016 |  | 2015
IPL |  | $104 |  |  |  | $93 |
WPL | 72 |  |  | 54 |
ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties were as follows (in millions):
| 2016 |  | 2015 |  | 2014
ATC billings to WPL |  | $110 |  |  |  | $101 |  |  |  | $96 |
WPL billings to ATC | 13 |  |  | 13 |  |  | 9 |
As of December 31, 2016 and 2015, WPL owed ATC net amounts of $8 million and $8 million, respectively. Refer to Note 6(a) for discussion of WPL’s transfer of its investment in ATC to ATI on December 31, 2016. WPL’s Sheboygan Falls Lease - Refer to Note 10(b) for discussion of WPL’s Sheboygan Falls lease. Franklin County Wind Farm - Refer to Note 3 for discussion of a February 2017 FERC order approving the transfer of the Franklin County wind farm from AEF to IPL. Alliant Energy and IPL currently expect to complete this transfer in 2017.
WPL [Member] |
Related Party Transaction [Line Items] |
Related Parties | RELATED PARTIES Service Agreements - IPL and WPL are parties to service agreements with an affiliate, Corporate Services. Pursuant to these service agreements, IPL and WPL receive various administrative and general 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 were as follows (in millions):
| IPL |  | WPL
| 2016 |  | 2015 |  | 2014 |  | 2016 |  | 2015 |  | 2014
Corporate Services billings |  | $161 |  |  |  | $150 |  |  |  | $148 |  |  |  | $133 |  |  |  | $121 |  |  |  | $116 |
Sales credited | 8 |  |  | 10 |  | 8 |  | 7 |  |  | 24 |  | 6
Purchases billed | 433 |  |  | 366 |  | 422 |  | 102 |  |  | 66 |  | 125
As of December 31, net intercompany payables to Corporate Services were as follows (in millions):
| 2016 |  | 2015
IPL |  | $104 |  |  |  | $93 |
WPL | 72 |  |  | 54 |
ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties were as follows (in millions):
| 2016 |  | 2015 |  | 2014
ATC billings to WPL |  | $110 |  |  |  | $101 |  |  |  | $96 |
WPL billings to ATC | 13 |  |  | 13 |  |  | 9 |
As of December 31, 2016 and 2015, WPL owed ATC net amounts of $8 million and $8 million, respectively. Refer to Note 6(a) for discussion of WPL’s transfer of its investment in ATC to ATI on December 31, 2016. WPL’s Sheboygan Falls Lease - Refer to Note 10(b) for discussion of WPL’s Sheboygan Falls lease. Franklin County Wind Farm - Refer to Note 3 for discussion of a February 2017 FERC order approving the transfer of the Franklin County wind farm from AEF to IPL. Alliant Energy and IPL currently expect to complete this transfer in 2017.

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