Related Parties (Tables)

6 Months Ended

Jun. 30, 2018

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
	2018		2017		2018		2017		2018		2017		2018		2017
Corporate Services billings		$44		$43		$85		$82		$34		$32		$67		$63
Sales credited	18		5		23		7		8		2		9		2
Purchases billed	80		96		173		162		20		33		37		67

Net Intercompany Payables

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2018	December 31, 2017	June 30, 2018	December 31, 2017
Net payables to Corporate Services	$102	$114	$63	$61

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
	2018		2017		2018		2017
ATC billings to WPL		$26		$27		$53		$53
WPL billings to ATC	3		3		5		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
	2018		2017		2018		2017		2018		2017		2018		2017
Corporate Services billings		$44		$43		$85		$82		$34		$32		$67		$63
Sales credited	18		5		23		7		8		2		9		2
Purchases billed	80		96		173		162		20		33		37		67

Net Intercompany Payables

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2018	December 31, 2017	June 30, 2018	December 31, 2017
Net payables to Corporate Services	$102	$114	$63	$61

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
	2018		2017		2018		2017		2018		2017		2018		2017
Corporate Services billings		$44		$43		$85		$82		$34		$32		$67		$63
Sales credited	18		5		23		7		8		2		9		2
Purchases billed	80		96		173		162		20		33		37		67

Net Intercompany Payables

Net intercompany payables to Corporate Services were as follows (in millions):

	IPL		WPL
	June 30, 2018	December 31, 2017	June 30, 2018	December 31, 2017
Net payables to Corporate Services	$102	$114	$63	$61

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
	2018		2017		2018		2017
ATC billings to WPL		$26		$27		$53		$53
WPL billings to ATC	3		3		5		6