Receivables (Tables)

12 Months Ended

Dec. 31, 2017

Accounts, Notes, Loans and Financing Receivable [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy						IPL						WPL
	2017			2016			2017			2016			2017			2016
Customer		$103.3			$111.7			$—			$—			$97.7			$104.4
Unbilled utility revenues	85.1			90.2			—			—			85.1			90.2
Deferred proceeds	222.1			211.1			222.1			211.1			—			—
Other	84.3			89.0			44.1			30.7			40.1			38.8
Allowance for doubtful accounts	(12.0		)	(8.7		)	(1.3		)	(1.1		)	(10.7		)	(7.1		)
		$482.8			$493.3			$264.9			$240.7			$212.2			$226.3

Maximum And Average Outstanding Cash Proceeds

IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):

	Maximum			Average
	2017	2016	2015	2017	2016	2015
Outstanding aggregate cash proceeds	$112.0	$172.0	$137.0	$62.2	$73.2	$46.7

Receivables Sold Under The Agreement

As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2017	2016
Customer accounts receivable	$133.8	$157.6
Unbilled utility revenues	112.7	90.4
Other receivables	0.3	0.1
Receivables sold to third party	246.8	248.1
Less: cash proceeds (a)	12.0	21.0
Deferred proceeds	234.8	227.1
Less: allowance for doubtful accounts	12.7	16.0
Fair value of deferred proceeds	$222.1	$211.1
Outstanding receivables past due	$44.7	$68.0

(a) Changes in cash proceeds are presented in “Sales of accounts receivable” in operating activities in Alliant Energy’s and IPL’s cash flows statements.

Additional Attributes Of Receivables Sold Under The Agreement

Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2017	2016	2015
Collections reinvested in receivables	$1,647.1	$1,818.1	$1,812.9
Write-offs, net of recoveries	17.7	4.8	8.8

IPL [Member]

Accounts, Notes, Loans and Financing Receivable [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy						IPL						WPL
	2017			2016			2017			2016			2017			2016
Customer		$103.3			$111.7			$—			$—			$97.7			$104.4
Unbilled utility revenues	85.1			90.2			—			—			85.1			90.2
Deferred proceeds	222.1			211.1			222.1			211.1			—			—
Other	84.3			89.0			44.1			30.7			40.1			38.8
Allowance for doubtful accounts	(12.0		)	(8.7		)	(1.3		)	(1.1		)	(10.7		)	(7.1		)
		$482.8			$493.3			$264.9			$240.7			$212.2			$226.3

Maximum And Average Outstanding Cash Proceeds

IPL’s maximum and average outstanding aggregate cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program were as follows (in millions):

	Maximum			Average
	2017	2016	2015	2017	2016	2015
Outstanding aggregate cash proceeds	$112.0	$172.0	$137.0	$62.2	$73.2	$46.7

Receivables Sold Under The Agreement

As of December 31, the attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2017	2016
Customer accounts receivable	$133.8	$157.6
Unbilled utility revenues	112.7	90.4
Other receivables	0.3	0.1
Receivables sold to third party	246.8	248.1
Less: cash proceeds (a)	12.0	21.0
Deferred proceeds	234.8	227.1
Less: allowance for doubtful accounts	12.7	16.0
Fair value of deferred proceeds	$222.1	$211.1
Outstanding receivables past due	$44.7	$68.0

(a) Changes in cash proceeds are presented in “Sales of accounts receivable” in operating activities in Alliant Energy’s and IPL’s cash flows statements.

Additional Attributes Of Receivables Sold Under The Agreement

Additional attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

	2017	2016	2015
Collections reinvested in receivables	$1,647.1	$1,818.1	$1,812.9
Write-offs, net of recoveries	17.7	4.8	8.8

WPL [Member]

Accounts, Notes, Loans and Financing Receivable [Line Items]

Accounts Receivable Details

Details for accounts receivable included on the balance sheets as of December 31 were as follows (in millions):

	Alliant Energy						IPL						WPL
	2017			2016			2017			2016			2017			2016
Customer		$103.3			$111.7			$—			$—			$97.7			$104.4
Unbilled utility revenues	85.1			90.2			—			—			85.1			90.2
Deferred proceeds	222.1			211.1			222.1			211.1			—			—
Other	84.3			89.0			44.1			30.7			40.1			38.8
Allowance for doubtful accounts	(12.0		)	(8.7		)	(1.3		)	(1.1		)	(10.7		)	(7.1		)
		$482.8			$493.3			$264.9			$240.7			$212.2			$226.3