Commitments And Contingencies (Tables)

3 Months Ended

Mar. 31, 2015

Commitments and Contingencies [Line Items]

Operating Expense Purchase Obligations

At March 31, 2015, minimum future commitments related to these operating expense purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a):
DAEC (IPL)		$1,510		$1,510		$—
Other	220		1		219
	1,730		1,511		219
Natural gas	228		120		108
Coal (b)	264		113		151
SO2 emission allowances	22		22		—
Other (c)	39		29		10
		$2,283		$1,795		$488

(a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2015 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2015.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2015, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, were as follows (in millions):

	Alliant Energy				IPL				WPL
Range of estimated future costs		$14	-	$34		$13	-	$31		$1	-	$3
Current and non-current environmental liabilities	16				14				2

IPL [Member]

Commitments and Contingencies [Line Items]

Operating Expense Purchase Obligations

At March 31, 2015, minimum future commitments related to these operating expense purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a):
DAEC (IPL)		$1,510		$1,510		$—
Other	220		1		219
	1,730		1,511		219
Natural gas	228		120		108
Coal (b)	264		113		151
SO2 emission allowances	22		22		—
Other (c)	39		29		10
		$2,283		$1,795		$488

(a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2015 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2015.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2015, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, were as follows (in millions):

	Alliant Energy				IPL				WPL
Range of estimated future costs		$14	-	$34		$13	-	$31		$1	-	$3
Current and non-current environmental liabilities	16				14				2

WPL [Member]

Commitments and Contingencies [Line Items]

Operating Expense Purchase Obligations

At March 31, 2015, minimum future commitments related to these operating expense purchase obligations were as follows (in millions):

	Alliant Energy		IPL		WPL
Purchased power (a):
DAEC (IPL)		$1,510		$1,510		$—
Other	220		1		219
	1,730		1,511		219
Natural gas	228		120		108
Coal (b)	264		113		151
SO2 emission allowances	22		22		—
Other (c)	39		29		10
		$2,283		$1,795		$488

(a) Includes payments required by PPAs for capacity rights and minimum quantities of MWhs required to be purchased.

(b) Corporate Services entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. These commitments were assigned to IPL and WPL based on information available as of March 31, 2015 regarding expected future usage, which is subject to change.

(c) Includes individual commitments incurred during the normal course of business that exceeded $1 million at March 31, 2015.

MGP Site Estimated Future Costs And Recorded Liabilities

At March 31, 2015, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, were as follows (in millions):

	Alliant Energy				IPL				WPL
Range of estimated future costs		$14	-	$34		$13	-	$31		$1	-	$3
Current and non-current environmental liabilities	16				14				2