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Benefit Plans (Tables)
 12 Months Ended
Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]  
Assumptions Used To Measure Benefit Plans
The assumptions for defined benefit pension and other postretirement benefits plans at the measurement date of December 31 were as follows (Not Applicable (N/A)):
Alliant Energy
Defined Benefit Pension Plans
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.11%
 
4.86%
 
5.56%
 
3.82%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.86%
 
5.56%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.50%
 
7.00%
 
6.90%
Rate of compensation increase
3.50
%
-
4.50%
 
3.50
%
-
4.50%
 
3.50
%
-
4.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
IPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.20%
 
4.95%
 
5.70%
 
3.76%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.95%
 
5.70%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.40%
 
7.30%
 
7.10%
Rate of compensation increase
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
WPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.20%
 
4.95%
 
5.70%
 
3.81%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.95%
 
5.70%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.00%
 
6.30%
 
6.30%
Rate of compensation increase
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
Medical Cost Trend On Covered Charges
A 1% change in the medical trend rates for 2012, holding all other assumptions constant, would have the following effects (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
1% Increase
 
1% Decrease
 
1% Increase
 
1% Decrease
 
1% Increase
 
1% Decrease
Effect on total of service and interest cost components

$0.4

 

($0.4
)
 

$0.2

 

($0.2
)
 

$0.2

 

($0.2
)
Effect on postretirement benefit obligation
2.6

 
(2.4
)
 
1.2

 
(1.1
)
 
1.2

 
(1.2
)
Defined Benefit Pension And Other Postretirement Benefits Plans
The “Directly assigned defined benefit pension plans” tables below include amounts directly assigned to each of IPL and WPL related to IPL’s and WPL’s current and former non-bargaining employees who are participants in Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.
Alliant Energy
Defined Benefit Pension Plans
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$13.5

 

$11.4

 

$11.9

 

$6.9

 

$7.0

 

$9.3

Interest cost
51.6

 
52.0

 
52.3

 
10.2

 
12.3

 
14.9

Expected return on plan assets (b)
(68.8
)
 
(63.8
)
 
(62.1
)
 
(7.5
)
 
(7.9
)
 
(7.7
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Transition obligation
—

 
—

 
—

 
—

 
—

 
0.1

Prior service cost (credit)
0.3

 
0.7

 
0.9

 
(12.0
)
 
(10.0
)
 
(2.4
)
Actuarial loss
33.3

 
21.1

 
23.8

 
6.3

 
5.3

 
7.4

Additional benefit costs (d)
0.1

 
10.2

 
—

 
—

 
—

 
—

Settlement losses (e)
5.4

 
1.1

 
1.4

 
—

 
—

 
—

 

$35.4

 

$32.7

 

$28.2

 

$3.9

 

$6.7

 

$21.6

IPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$7.5

 

$6.1

 

$6.2

 

$3.0

 

$2.6

 

$3.4

Interest cost
17.1

 
16.7

 
16.5

 
4.4

 
5.5

 
6.8

Expected return on plan assets (b)
(23.0
)
 
(20.0
)
 
(19.5
)
 
(5.1
)
 
(5.4
)
 
(5.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Transition obligation
—

 
—

 
—

 
—

 
—

 
0.1

Prior service cost (credit)
0.4

 
0.5

 
0.6

 
(6.3
)
 
(5.0
)
 
(1.1
)
Actuarial loss
10.2

 
5.7

 
7.2

 
3.5

 
2.9

 
4.0

 

$12.2

 

$9.0

 

$11.0

 

($0.5
)
 

$0.6

 

$7.9

WPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$5.2

 

$4.5

 

$4.9

 

$2.7

 

$2.9

 

$3.6

Interest cost
16.4

 
16.1

 
15.7

 
4.1

 
4.9

 
5.5

Expected return on plan assets (b)
(22.3
)
 
(20.0
)
 
(19.1
)
 
(1.3
)
 
(1.3
)
 
(1.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Prior service cost (credit)
0.5

 
0.5

 
0.5

 
(3.9
)
 
(3.4
)
 
(0.7
)
Actuarial loss
12.1

 
7.1

 
8.5

 
2.3

 
2.1

 
2.5

Additional benefit costs
0.1

 
—

 
—

 
—

 
—

 
—

 

$12.0

 

$8.2

 

$10.5

 

$3.9

 

$5.2

 

$9.6

Directly assigned defined benefit pension plans
IPL
 
WPL
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Interest cost

$7.0

 

$7.3

 

$7.8

 

$5.2

 

$5.5

 

$5.6

Expected return on plan assets (b)
(9.6
)
 
(9.7
)
 
(9.7
)
 
(7.3
)
 
(7.3
)
 
(7.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Prior service credit
(0.2
)
 
(0.2
)
 
(0.3
)
 
(0.1
)
 
(0.2
)
 
(0.2
)
Actuarial loss
3.9

 
3.0

 
2.9

 
3.6

 
3.0

 
2.8

Additional benefit costs (d)
—

 
2.8

 
—

 
—

 
0.7

 
—

 

$1.1

 

$3.2

 

$0.7

 

$1.4

 

$1.7

 

$0.9


(a)
In 2011, Alliant Energy, IPL and WPL amended their defined benefit postretirement health care plans resulting in a revision to the method and level of coverage provided for participants more than 65 years of age. This amendment was determined to be a significant event, which required Alliant Energy, IPL and WPL to remeasure their defined benefit postretirement health care plans in 2011. The amendment resulted in a decrease in Alliant Energy’s, IPL’s and WPL’s postretirement benefit obligations of $55 million, $30 million and $16 million, respectively, in 2011 with the impact of the remeasurement on net periodic benefit costs being recognized prospectively from the remeasurement date. The impact of the remeasurement decreased Alliant Energy’s, IPL’s and WPL’s net periodic benefit costs by $11.3 million, $7.2 million, and $3.8 million in 2011, respectively. The discount rate used for the remeasurement was 5.20%. All other assumptions used for the remeasurement were consistent with the measurement assumptions used at December 31, 2010.
(b)
The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.
(c)
Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan (Cash Balance Plan) where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits. Unrecognized prior service costs (credits) for the postretirement benefits plans are amortized over the average future service period to full eligibility of the participants of each plan.
(d)
Alliant Energy reached an agreement with the IRS, which resulted in a favorable determination letter for the Cash Balance Plan in 2011. The agreement with the IRS required Alliant Energy to amend the Cash Balance Plan, which was completed in 2011 resulting in aggregate additional benefits of $10.2 million paid by Alliant Energy to certain former participants in the Cash Balance Plan in 2011. Alliant Energy recognized $10.2 million of additional benefits costs in 2011 related to these benefits. IPL recognized $6.3 million ($2.8 million directly assigned and $3.5 million allocated by Corporate Services) and WPL recognized $3.4 million ($0.7 million directly assigned and $2.7 million allocated by Corporate Services) of additional benefits costs in 2011 related to these benefits. Refer to Note 13(c) for additional information regarding the Cash Balance Plan.
(e)
Settlement losses related to payments made to retired executives of Alliant Energy.
Schedule Of Qualified And Non-Qualified Pension And Other Postretirement Benefits Costs
The following table includes the allocated qualified and non-qualified pension and other postretirement benefits costs associated with Corporate Services employees providing services to IPL and WPL (in millions):
 
Pension Benefits Costs (a)
 
Other Postretirement Benefits Costs
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
IPL

$4.9

 

$5.8

 

$2.9

 

$0.1

 

$0.3

 

$2.0

WPL
3.6

 
4.2

 
1.9

 
0.1

 
0.2

 
1.3


(a)
Includes settlement losses related to payments made to retired executives of Alliant Energy in 2012. In 2011, additional qualified pension benefits costs resulting from the 2011 amendment to the Cash Balance Plan allocated to IPL and WPL by Corporate Services were $3.5 million and $2.7 million, respectively.
Estimated Amortization From Regulatory Assets And Regulatory Liabilities On The Consolidated Balance Sheets And Accumulated Other Comprehensive Loss On Alliant Energy's Consolidated Balance Sheet Into Net Periodic Benefit Cost
The estimated amortization from “Regulatory assets” and “Regulatory liabilities” on the Consolidated Balance Sheets and AOCL on Alliant Energy’s Consolidated Balance Sheet into net periodic benefit cost in 2013 is as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
 
 
Other
 
Qualified
 
Other
 
Qualified
 
Other
 
Defined Benefit
 
Postretirement
 
Defined Benefit
 
Postretirement
 
Defined Benefit
 
Postretirement
 
Pension Plans
 
Benefits Plans
 
Pension Plan
 
Benefits Plans
 
Pension Plan
 
Benefits Plans
Actuarial loss

$36.2

 

$4.9

 

$10.9

 

$2.7

 

$13.2

 

$1.9

Prior service cost (credit)
0.2

 
(11.9
)
 
0.4

 
(6.3
)
 
0.5

 
(3.9
)
 

$36.4

 

($7.0
)
 

$11.3

 

($3.6
)
 

$13.7

 

($2.0
)
Directly assigned defined benefit pension plans
IPL
 
WPL
Actuarial loss

$4.2

 

$3.9

Prior service credit
(0.2
)
 
(0.2
)
 

$4.0

 

$3.7
Funded Status Of Benefit Plans
A reconciliation of the funded status of Alliant Energy’s qualified and non-qualified defined benefit pension and other postretirement benefits plans to the amounts recognized on Alliant Energy’s Consolidated Balance Sheets at December 31 was as follows (in millions):
Alliant Energy
Defined Benefit
 
Other Postretirement
 
Pension Plans
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Change in projected benefit obligation:
 
 
 
 
 
 
 
Net projected benefit obligation at January 1

$1,081.4

 

$953.0

 

$224.2

 

$274.9

Service cost
13.5

 
11.4

 
6.9

 
7.0

Interest cost
51.6

 
52.0

 
10.2

 
12.3

Plan participants’ contributions
—

 
—

 
2.7

 
6.4

Plan amendments (a)
—

 
10.2

 
—

 
(56.6
)
Additional benefit costs
0.1

 
—

 
—

 
—

Actuarial (gain) loss
135.4

 
126.2

 
(1.6
)
 
(0.8
)
Early Retiree Reinsurance Program (ERRP) proceeds
—

 
—

 
—

 
0.6

Gross benefits paid
(74.5
)
 
(71.4
)
 
(19.2
)
 
(20.8
)
Federal subsidy on other postretirement benefits paid
—

 
—

 
—

 
1.2

Net projected benefit obligation at December 31
1,207.5

 
1,081.4

 
223.2

 
224.2

Change in plan assets:
 
 
 
 
 
 
 
Fair value of plan assets at January 1
897.4

 
823.0

 
120.4

 
122.7

Actual return on plan assets
126.9

 
28.9

 
14.3

 
2.6

Employer contributions
15.8

 
116.9

 
4.9

 
9.5

Plan participants’ contributions
—

 
—

 
2.7

 
6.4

Gross benefits paid
(74.5
)
 
(71.4
)
 
(19.2
)
 
(20.8
)
Fair value of plan assets at December 31
965.6

 
897.4

 
123.1

 
120.4

Under funded status at December 31

($241.9
)
 

($184.0
)
 

($100.1
)
 

($103.8
)

Alliant Energy
Defined Benefit
 
Other Postretirement
 
Pension Plans
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Amounts recognized on the Consolidated Balance Sheets consist of:
 
 
 
 
 
 
 
Non-current assets

$—

 

$—

 

$3.5

 

$1.3

Other current liabilities
(2.4
)
 
(4.6
)
 
(2.8
)
 
—

Pension and other benefit obligations
(239.5
)
 
(179.4
)
 
(100.8
)
 
(105.1
)
Net amount recognized at December 31

($241.9
)
 

($184.0
)
 

($100.1
)
 

($103.8
)
Amounts recognized in Regulatory Assets, Regulatory Liabilities and AOCL consist of (b):
 
 
 
 
 
 
 
Net actuarial loss

$533.4

 

$494.8

 

$62.1

 

$76.7

Prior service credit
(7.2
)
 
(6.9
)
 
(40.5
)
 
(52.5
)
 

$526.2

 

$487.9

 

$21.6

 

$24.2


(a)
Refer to “Net Periodic Benefit Costs” above for additional information regarding plan amendments to the defined benefit pension and other postretirement benefits plans in 2011.
(b)
Refer to Note 1(b) and Alliant Energy’s Consolidated Statements of Common Equity for amounts recognized in “Regulatory assets” and “AOCL,” respectively, on Alliant Energy’s Consolidated Balance Sheets. At December 31, 2012 and 2011, $2.7 million and $3.3 million, respectively, of regulatory liabilities were recognized related to Alliant Energy’s other postretirement benefits plans.
Accumulated Benefit Obligations
Included in the following tables are accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and other postretirement benefits plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date (Not Applicable (N/A); in millions):
Alliant Energy
Defined Benefit
 
Other Postretirement
 
Pension Plans
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$1,155.5

 

$1,029.4

 

$223.2

 

$224.2

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
1,155.5

 
1,029.4

 
223.2

 
224.2

Fair value of plan assets
965.6

 
897.4

 
123.1

 
120.4

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
1,207.5

 
1,081.4

 
N/A

 
N/A

Fair value of plan assets
965.6

 
897.4

 
N/A

 
N/A


IPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$359.6

 

$314.6

 

$96.0

 

$97.5

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
359.6

 
314.6

 
96.0

 
97.5

Fair value of plan assets
322.3

 
298.7

 
78.8

 
74.7

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
388.4

 
344.5

 
N/A

 
N/A

Fair value of plan assets
322.3

 
298.7

 
N/A

 
N/A


WPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$363.7

 

$314.7

 

$89.1

 

$89.6

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
363.7

 
314.7

 
89.1

 
89.6

Fair value of plan assets
313.2

 
289.6

 
22.3

 
25.1

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
380.2

 
332.5

 
N/A

 
N/A

Fair value of plan assets
313.2

 
289.6

 
N/A

 
N/A
Regulatory Assets and Regulatory Liabilities
In addition to the amounts recognized in “Regulatory assets and regulatory liabilities” in the above tables for IPL and WPL, “Regulatory assets” and “Regulatory liabilities” were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):
 
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Regulatory assets

$38.1

 

$33.7

 

$25.5

 

$22.3

Regulatory liabilities
0.6

 
0.3

 
0.4

 
0.2
Estimated Future Employer Contributions
Alliant Energy, IPL and WPL estimate that funding for the qualified defined benefit pension, non-qualified defined benefit pension and other postretirement benefits plans, and the directly assigned qualified and non-qualified defined benefit pension plans amounts, during 2013 will be as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
Qualified defined benefit pension plans

$—

 

$—

 

$—

Non-qualified defined benefit pension plans (a)
2.4

 
N/A

 
N/A

Directly assigned defined benefit pension plans (b)
N/A

 
0.8

 
0.2

Other postretirement benefits plans
3.0

 
—

 
3.0


(a)
Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans.
(b)
Amounts directly assigned to IPL and WPL for non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.
Expected Benefit Payments
Expected benefit payments, and the directly assigned qualified and non-qualified defined benefit pension benefits amounts, which reflect expected future service, as appropriate, are as follows (in millions):
Alliant Energy
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified and non-qualified defined benefit pension benefits

$61.9

 

$64.7

 

$68.5

 

$66.6

 

$69.2

 

$374.1

Other postretirement benefits
16.6

 
16.2

 
16.3

 
16.4

 
16.6

 
84.2

 

$78.5

 

$80.9

 

$84.8

 

$83.0

 

$85.8

 

$458.3

IPL
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified defined benefit pension benefits

$15.9

 

$16.9

 

$17.9

 

$18.9

 

$20.0

 

$116.0

Directly assigned defined benefit pension benefits
12.6

 
13.4

 
14.1

 
12.1

 
13.5

 
60.2

Other postretirement benefits
8.0

 
7.3

 
7.2

 
7.1

 
7.2

 
35.9

 

$36.5

 

$37.6

 

$39.2

 

$38.1

 

$40.7

 

$212.1

WPL
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified defined benefit pension benefits

$14.4

 

$15.2

 

$16.1

 

$17.0

 

$18.0

 

$108.7

Directly assigned defined benefit pension benefits
10.5

 
10.2

 
11.4

 
9.8

 
9.5

 
43.0

Other postretirement benefits
6.3

 
6.5

 
6.7

 
6.7

 
6.8

 
34.3

 

$31.2

 

$31.9

 

$34.2

 

$33.5

 

$34.3

 

$186.0
Plan Assets And Plan Assets Percentage Associated With Entity's Benefit Plans
At December 31, the fair values of IPL’s and WPL’s qualified and non-qualified defined benefit pension plan assets associated with IPL’s and WPL’s current and former non-bargaining employees who are participants in Alliant Energy and Corporate Services sponsored plans that were directly assigned to IPL and WPL, along with the percentage these assets represent of the fair values by asset category and fair value hierarchy level shown in the above table were as follows (dollars in millions):
 
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Fair values of directly assigned amounts
$136.5
 
$127.4
 
$102.2
 
$97.0
Percentage represented
14.1%
 
14.2%
 
10.6%
 
10.8%
Recognized Compensation Expense And Income Tax Benefits
A summary of compensation expense (allocated to IPL and WPL) and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Compensation expense

$6.9

 

$10.1

 

$7.5

 

$3.6

 

$5.5

 

$4.0

 

$3.0

 

$4.1

 

$3.0

Income tax benefits
2.8

 
4.0

 
3.0

 
1.5

 
2.2

 
1.6

 
1.2

 
1.7

 
1.2
Schedule Of Equity-based Compensation Plans Activity
Information related to fair values of nonvested performance shares and units at December 31, 2012, by year of grant, were as follows:
 
Performance Shares
 
Performance Units
 
2012 Grant
 
2011 Grant
 
2010 Grant
 
2012 Grant
 
2011 Grant
 
2010 Grant
Nonvested awards
45,612

 
45,235

 
54,430

 
23,969

 
21,095

 
19,905

Alliant Energy common stock closing price on December 31, 2012

$43.91

 

$43.91

 

$43.91

 
 
 
 
 
 
Alliant Energy common stock average price on grant date
 
 
 
 
 
 

$43.05

 

$38.75

 

$32.56

Estimated payout percentage based on performance criteria
89
%
 
107
%
 
198
%
 
89
%
 
107
%
 
198
%
Fair values of each nonvested award

$39.08

 

$46.98

 

$86.72

 

$38.31

 

$41.46

 

$64.30
Disclosure Of Other Stock Option Activity
Other information related to stock option activity was as follows (in millions):
 
2012
 
2011
 
2010
Cash received from stock options exercised

$0.9

 

$2.5

 

$5.5

Aggregate intrinsic value of stock options exercised
0.8

 
1.6

 
1.1

Income tax benefit from the exercise of stock options
0.3

 
0.7

 
0.4
Carrying Value Of Entity's Deferred Compensation Obligations Interest And Equity Accounts
At December 31, the carrying value of Alliant Energy’s and IPL’s deferred compensation obligations for participants’ interest and equity accounts was as follows (in millions):
 
Alliant Energy
 
IPL
 
2012
 
2011
 
2012
 
2011
Carrying value
$16.3
 
$20.5
 
$5.0
 
$5.0
IPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Assumptions Used To Measure Benefit Plans
The assumptions for defined benefit pension and other postretirement benefits plans at the measurement date of December 31 were as follows (Not Applicable (N/A)):
Alliant Energy
Defined Benefit Pension Plans
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.11%
 
4.86%
 
5.56%
 
3.82%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.86%
 
5.56%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.50%
 
7.00%
 
6.90%
Rate of compensation increase
3.50
%
-
4.50%
 
3.50
%
-
4.50%
 
3.50
%
-
4.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
IPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.20%
 
4.95%
 
5.70%
 
3.76%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.95%
 
5.70%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.40%
 
7.30%
 
7.10%
Rate of compensation increase
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
WPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.20%
 
4.95%
 
5.70%
 
3.81%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.95%
 
5.70%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.00%
 
6.30%
 
6.30%
Rate of compensation increase
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
Medical Cost Trend On Covered Charges
A 1% change in the medical trend rates for 2012, holding all other assumptions constant, would have the following effects (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
1% Increase
 
1% Decrease
 
1% Increase
 
1% Decrease
 
1% Increase
 
1% Decrease
Effect on total of service and interest cost components

$0.4

 

($0.4
)
 

$0.2

 

($0.2
)
 

$0.2

 

($0.2
)
Effect on postretirement benefit obligation
2.6

 
(2.4
)
 
1.2

 
(1.1
)
 
1.2

 
(1.2
)
Defined Benefit Pension And Other Postretirement Benefits Plans
The “Directly assigned defined benefit pension plans” tables below include amounts directly assigned to each of IPL and WPL related to IPL’s and WPL’s current and former non-bargaining employees who are participants in Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.
Alliant Energy
Defined Benefit Pension Plans
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$13.5

 

$11.4

 

$11.9

 

$6.9

 

$7.0

 

$9.3

Interest cost
51.6

 
52.0

 
52.3

 
10.2

 
12.3

 
14.9

Expected return on plan assets (b)
(68.8
)
 
(63.8
)
 
(62.1
)
 
(7.5
)
 
(7.9
)
 
(7.7
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Transition obligation
—

 
—

 
—

 
—

 
—

 
0.1

Prior service cost (credit)
0.3

 
0.7

 
0.9

 
(12.0
)
 
(10.0
)
 
(2.4
)
Actuarial loss
33.3

 
21.1

 
23.8

 
6.3

 
5.3

 
7.4

Additional benefit costs (d)
0.1

 
10.2

 
—

 
—

 
—

 
—

Settlement losses (e)
5.4

 
1.1

 
1.4

 
—

 
—

 
—

 

$35.4

 

$32.7

 

$28.2

 

$3.9

 

$6.7

 

$21.6

IPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$7.5

 

$6.1

 

$6.2

 

$3.0

 

$2.6

 

$3.4

Interest cost
17.1

 
16.7

 
16.5

 
4.4

 
5.5

 
6.8

Expected return on plan assets (b)
(23.0
)
 
(20.0
)
 
(19.5
)
 
(5.1
)
 
(5.4
)
 
(5.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Transition obligation
—

 
—

 
—

 
—

 
—

 
0.1

Prior service cost (credit)
0.4

 
0.5

 
0.6

 
(6.3
)
 
(5.0
)
 
(1.1
)
Actuarial loss
10.2

 
5.7

 
7.2

 
3.5

 
2.9

 
4.0

 

$12.2

 

$9.0

 

$11.0

 

($0.5
)
 

$0.6

 

$7.9

WPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$5.2

 

$4.5

 

$4.9

 

$2.7

 

$2.9

 

$3.6

Interest cost
16.4

 
16.1

 
15.7

 
4.1

 
4.9

 
5.5

Expected return on plan assets (b)
(22.3
)
 
(20.0
)
 
(19.1
)
 
(1.3
)
 
(1.3
)
 
(1.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Prior service cost (credit)
0.5

 
0.5

 
0.5

 
(3.9
)
 
(3.4
)
 
(0.7
)
Actuarial loss
12.1

 
7.1

 
8.5

 
2.3

 
2.1

 
2.5

Additional benefit costs
0.1

 
—

 
—

 
—

 
—

 
—

 

$12.0

 

$8.2

 

$10.5

 

$3.9

 

$5.2

 

$9.6

Directly assigned defined benefit pension plans
IPL
 
WPL
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Interest cost

$7.0

 

$7.3

 

$7.8

 

$5.2

 

$5.5

 

$5.6

Expected return on plan assets (b)
(9.6
)
 
(9.7
)
 
(9.7
)
 
(7.3
)
 
(7.3
)
 
(7.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Prior service credit
(0.2
)
 
(0.2
)
 
(0.3
)
 
(0.1
)
 
(0.2
)
 
(0.2
)
Actuarial loss
3.9

 
3.0

 
2.9

 
3.6

 
3.0

 
2.8

Additional benefit costs (d)
—

 
2.8

 
—

 
—

 
0.7

 
—

 

$1.1

 

$3.2

 

$0.7

 

$1.4

 

$1.7

 

$0.9


(a)
In 2011, Alliant Energy, IPL and WPL amended their defined benefit postretirement health care plans resulting in a revision to the method and level of coverage provided for participants more than 65 years of age. This amendment was determined to be a significant event, which required Alliant Energy, IPL and WPL to remeasure their defined benefit postretirement health care plans in 2011. The amendment resulted in a decrease in Alliant Energy’s, IPL’s and WPL’s postretirement benefit obligations of $55 million, $30 million and $16 million, respectively, in 2011 with the impact of the remeasurement on net periodic benefit costs being recognized prospectively from the remeasurement date. The impact of the remeasurement decreased Alliant Energy’s, IPL’s and WPL’s net periodic benefit costs by $11.3 million, $7.2 million, and $3.8 million in 2011, respectively. The discount rate used for the remeasurement was 5.20%. All other assumptions used for the remeasurement were consistent with the measurement assumptions used at December 31, 2010.
(b)
The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.
(c)
Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan (Cash Balance Plan) where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits. Unrecognized prior service costs (credits) for the postretirement benefits plans are amortized over the average future service period to full eligibility of the participants of each plan.
(d)
Alliant Energy reached an agreement with the IRS, which resulted in a favorable determination letter for the Cash Balance Plan in 2011. The agreement with the IRS required Alliant Energy to amend the Cash Balance Plan, which was completed in 2011 resulting in aggregate additional benefits of $10.2 million paid by Alliant Energy to certain former participants in the Cash Balance Plan in 2011. Alliant Energy recognized $10.2 million of additional benefits costs in 2011 related to these benefits. IPL recognized $6.3 million ($2.8 million directly assigned and $3.5 million allocated by Corporate Services) and WPL recognized $3.4 million ($0.7 million directly assigned and $2.7 million allocated by Corporate Services) of additional benefits costs in 2011 related to these benefits. Refer to Note 13(c) for additional information regarding the Cash Balance Plan.
(e)
Settlement losses related to payments made to retired executives of Alliant Energy.
Schedule Of Qualified And Non-Qualified Pension And Other Postretirement Benefits Costs
The following table includes the allocated qualified and non-qualified pension and other postretirement benefits costs associated with Corporate Services employees providing services to IPL and WPL (in millions):
 
Pension Benefits Costs (a)
 
Other Postretirement Benefits Costs
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
IPL

$4.9

 

$5.8

 

$2.9

 

$0.1

 

$0.3

 

$2.0

WPL
3.6

 
4.2

 
1.9

 
0.1

 
0.2

 
1.3


(a)
Includes settlement losses related to payments made to retired executives of Alliant Energy in 2012. In 2011, additional qualified pension benefits costs resulting from the 2011 amendment to the Cash Balance Plan allocated to IPL and WPL by Corporate Services were $3.5 million and $2.7 million, respectively.
Estimated Amortization From Regulatory Assets And Regulatory Liabilities On The Consolidated Balance Sheets And Accumulated Other Comprehensive Loss On Alliant Energy's Consolidated Balance Sheet Into Net Periodic Benefit Cost
The estimated amortization from “Regulatory assets” and “Regulatory liabilities” on the Consolidated Balance Sheets and AOCL on Alliant Energy’s Consolidated Balance Sheet into net periodic benefit cost in 2013 is as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
 
 
Other
 
Qualified
 
Other
 
Qualified
 
Other
 
Defined Benefit
 
Postretirement
 
Defined Benefit
 
Postretirement
 
Defined Benefit
 
Postretirement
 
Pension Plans
 
Benefits Plans
 
Pension Plan
 
Benefits Plans
 
Pension Plan
 
Benefits Plans
Actuarial loss

$36.2

 

$4.9

 

$10.9

 

$2.7

 

$13.2

 

$1.9

Prior service cost (credit)
0.2

 
(11.9
)
 
0.4

 
(6.3
)
 
0.5

 
(3.9
)
 

$36.4

 

($7.0
)
 

$11.3

 

($3.6
)
 

$13.7

 

($2.0
)
Directly assigned defined benefit pension plans
IPL
 
WPL
Actuarial loss

$4.2

 

$3.9

Prior service credit
(0.2
)
 
(0.2
)
 

$4.0

 

$3.7
Funded Status Of Benefit Plans
A reconciliation of the funded status of IPL’s sponsored qualified defined benefit pension and other postretirement benefits plans to the amounts recognized on IPL’s Consolidated Balance Sheets, at December 31 was as follows (in millions):
IPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Change in projected benefit obligation:
 
 
 
 
 
 
 
Net projected benefit obligation at January 1

$344.5

 

$293.8

 

$97.5

 

$128.5

Service cost
7.5

 
6.1

 
3.0

 
2.6

Interest cost
17.1

 
16.7

 
4.4

 
5.5

Plan participants’ contributions
—

 
—

 
0.9

 
2.0

Plan amendments (a)
—

 
—

 
—

 
(30.1
)
Actuarial (gain) loss
38.2

 
45.2

 
(1.4
)
 
(2.7
)
ERRP proceeds
—

 
—

 
—

 
0.2

Gross benefits paid
(18.9
)
 
(17.3
)
 
(8.4
)
 
(9.1
)
Federal subsidy on other postretirement benefits paid
—

 
—

 
—

 
0.6

Net projected benefit obligation at December 31
388.4

 
344.5

 
96.0

 
97.5

Change in plan assets:
 
 
 
 
 
 
 
Fair value of plan assets at January 1
298.7

 
256.9

 
74.7

 
77.5

Actual return on plan assets
42.5

 
9.1

 
9.4

 
1.4

Employer contributions
—

 
50.0

 
2.2

 
2.9

Plan participants’ contributions
—

 
—

 
0.9

 
2.0

Gross benefits paid
(18.9
)
 
(17.3
)
 
(8.4
)
 
(9.1
)
Fair value of plan assets at December 31
322.3

 
298.7

 
78.8

 
74.7

Under funded status at December 31

($66.1
)
 

($45.8
)
 

($17.2
)
 

($22.8
)

IPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Amounts recognized on the Consolidated Balance Sheets consist of:
 
 
 
 
 
 
 
Pension and other benefit obligations

($66.1
)
 

($45.8
)
 

($17.2
)
 

($22.8
)
Amounts recognized in Regulatory Assets and Regulatory Liabilities consist of (b):
 
 
 
 
 
 
 
Net actuarial loss

$149.7

 

$141.1

 

$32.0

 

$41.0

Prior service cost (credit)
0.7

 
1.1

 
(21.3
)
 
(27.6
)
 

$150.4

 

$142.2

 

$10.7

 

$13.4


(a)
Refer to “Net Periodic Benefit Costs” above for additional information regarding plan amendments to the defined benefit pension and other postretirement benefits plans in 2011.
(b)
Refer to Note 1(b) for amounts recognized in “Regulatory assets” on IPL’s Consolidated Balance Sheets. At December 31, 2012 and 2011, $1.4 million and $2.8 million, respectively, of regulatory liabilities were recognized related to IPL’s other postretirement benefits plans.
Accumulated Benefit Obligations
Included in the following tables are accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and other postretirement benefits plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date (Not Applicable (N/A); in millions):
Alliant Energy
Defined Benefit
 
Other Postretirement
 
Pension Plans
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$1,155.5

 

$1,029.4

 

$223.2

 

$224.2

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
1,155.5

 
1,029.4

 
223.2

 
224.2

Fair value of plan assets
965.6

 
897.4

 
123.1

 
120.4

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
1,207.5

 
1,081.4

 
N/A

 
N/A

Fair value of plan assets
965.6

 
897.4

 
N/A

 
N/A


IPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$359.6

 

$314.6

 

$96.0

 

$97.5

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
359.6

 
314.6

 
96.0

 
97.5

Fair value of plan assets
322.3

 
298.7

 
78.8

 
74.7

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
388.4

 
344.5

 
N/A

 
N/A

Fair value of plan assets
322.3

 
298.7

 
N/A

 
N/A


WPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$363.7

 

$314.7

 

$89.1

 

$89.6

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
363.7

 
314.7

 
89.1

 
89.6

Fair value of plan assets
313.2

 
289.6

 
22.3

 
25.1

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
380.2

 
332.5

 
N/A

 
N/A

Fair value of plan assets
313.2

 
289.6

 
N/A

 
N/A
Regulatory Assets and Regulatory Liabilities
In addition to the amounts recognized in “Regulatory assets and regulatory liabilities” in the above tables for IPL and WPL, “Regulatory assets” and “Regulatory liabilities” were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):
 
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Regulatory assets

$38.1

 

$33.7

 

$25.5

 

$22.3

Regulatory liabilities
0.6

 
0.3

 
0.4

 
0.2
Estimated Future Employer Contributions
Alliant Energy, IPL and WPL estimate that funding for the qualified defined benefit pension, non-qualified defined benefit pension and other postretirement benefits plans, and the directly assigned qualified and non-qualified defined benefit pension plans amounts, during 2013 will be as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
Qualified defined benefit pension plans

$—

 

$—

 

$—

Non-qualified defined benefit pension plans (a)
2.4

 
N/A

 
N/A

Directly assigned defined benefit pension plans (b)
N/A

 
0.8

 
0.2

Other postretirement benefits plans
3.0

 
—

 
3.0


(a)
Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans.
(b)
Amounts directly assigned to IPL and WPL for non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.
Expected Benefit Payments
Expected benefit payments, and the directly assigned qualified and non-qualified defined benefit pension benefits amounts, which reflect expected future service, as appropriate, are as follows (in millions):
Alliant Energy
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified and non-qualified defined benefit pension benefits

$61.9

 

$64.7

 

$68.5

 

$66.6

 

$69.2

 

$374.1

Other postretirement benefits
16.6

 
16.2

 
16.3

 
16.4

 
16.6

 
84.2

 

$78.5

 

$80.9

 

$84.8

 

$83.0

 

$85.8

 

$458.3

IPL
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified defined benefit pension benefits

$15.9

 

$16.9

 

$17.9

 

$18.9

 

$20.0

 

$116.0

Directly assigned defined benefit pension benefits
12.6

 
13.4

 
14.1

 
12.1

 
13.5

 
60.2

Other postretirement benefits
8.0

 
7.3

 
7.2

 
7.1

 
7.2

 
35.9

 

$36.5

 

$37.6

 

$39.2

 

$38.1

 

$40.7

 

$212.1

WPL
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified defined benefit pension benefits

$14.4

 

$15.2

 

$16.1

 

$17.0

 

$18.0

 

$108.7

Directly assigned defined benefit pension benefits
10.5

 
10.2

 
11.4

 
9.8

 
9.5

 
43.0

Other postretirement benefits
6.3

 
6.5

 
6.7

 
6.7

 
6.8

 
34.3

 

$31.2

 

$31.9

 

$34.2

 

$33.5

 

$34.3

 

$186.0
Plan Assets And Plan Assets Percentage Associated With Entity's Benefit Plans
At December 31, the fair values of IPL’s and WPL’s qualified and non-qualified defined benefit pension plan assets associated with IPL’s and WPL’s current and former non-bargaining employees who are participants in Alliant Energy and Corporate Services sponsored plans that were directly assigned to IPL and WPL, along with the percentage these assets represent of the fair values by asset category and fair value hierarchy level shown in the above table were as follows (dollars in millions):
 
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Fair values of directly assigned amounts
$136.5
 
$127.4
 
$102.2
 
$97.0
Percentage represented
14.1%
 
14.2%
 
10.6%
 
10.8%
Recognized Compensation Expense And Income Tax Benefits
A summary of compensation expense (allocated to IPL and WPL) and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Compensation expense

$6.9

 

$10.1

 

$7.5

 

$3.6

 

$5.5

 

$4.0

 

$3.0

 

$4.1

 

$3.0

Income tax benefits
2.8

 
4.0

 
3.0

 
1.5

 
2.2

 
1.6

 
1.2

 
1.7

 
1.2
Carrying Value Of Entity's Deferred Compensation Obligations Interest And Equity Accounts
At December 31, the carrying value of Alliant Energy’s and IPL’s deferred compensation obligations for participants’ interest and equity accounts was as follows (in millions):
 
Alliant Energy
 
IPL
 
2012
 
2011
 
2012
 
2011
Carrying value
$16.3
 
$20.5
 
$5.0
 
$5.0
WPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Assumptions Used To Measure Benefit Plans
The assumptions for defined benefit pension and other postretirement benefits plans at the measurement date of December 31 were as follows (Not Applicable (N/A)):
Alliant Energy
Defined Benefit Pension Plans
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.11%
 
4.86%
 
5.56%
 
3.82%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.86%
 
5.56%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.50%
 
7.00%
 
6.90%
Rate of compensation increase
3.50
%
-
4.50%
 
3.50
%
-
4.50%
 
3.50
%
-
4.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
IPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.20%
 
4.95%
 
5.70%
 
3.76%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.95%
 
5.70%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.40%
 
7.30%
 
7.10%
Rate of compensation increase
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
WPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Discount rate for benefit obligations
4.20%
 
4.95%
 
5.70%
 
3.81%
 
4.60%
 
5.25%
Discount rate for net periodic cost
4.95%
 
5.70%
 
5.80%
 
4.60%
 
5.25%
 
5.55%
Expected rate of return on plan assets
7.90%
 
7.90%
 
8.00%
 
7.00%
 
6.30%
 
6.30%
Rate of compensation increase
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
 
3.50%
Medical cost trend on covered charges:
 
 
 
 
 
 
 
 
 
 
 
Initial trend rate (end of year)
N/A
 
N/A
 
N/A
 
7.50%
 
8.00%
 
7.00%
Ultimate trend rate
N/A
 
N/A
 
N/A
 
5.00%
 
5.00%
 
5.00%
Medical Cost Trend On Covered Charges
A 1% change in the medical trend rates for 2012, holding all other assumptions constant, would have the following effects (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
1% Increase
 
1% Decrease
 
1% Increase
 
1% Decrease
 
1% Increase
 
1% Decrease
Effect on total of service and interest cost components

$0.4

 

($0.4
)
 

$0.2

 

($0.2
)
 

$0.2

 

($0.2
)
Effect on postretirement benefit obligation
2.6

 
(2.4
)
 
1.2

 
(1.1
)
 
1.2

 
(1.2
)
Defined Benefit Pension And Other Postretirement Benefits Plans
The “Directly assigned defined benefit pension plans” tables below include amounts directly assigned to each of IPL and WPL related to IPL’s and WPL’s current and former non-bargaining employees who are participants in Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.
Alliant Energy
Defined Benefit Pension Plans
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$13.5

 

$11.4

 

$11.9

 

$6.9

 

$7.0

 

$9.3

Interest cost
51.6

 
52.0

 
52.3

 
10.2

 
12.3

 
14.9

Expected return on plan assets (b)
(68.8
)
 
(63.8
)
 
(62.1
)
 
(7.5
)
 
(7.9
)
 
(7.7
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Transition obligation
—

 
—

 
—

 
—

 
—

 
0.1

Prior service cost (credit)
0.3

 
0.7

 
0.9

 
(12.0
)
 
(10.0
)
 
(2.4
)
Actuarial loss
33.3

 
21.1

 
23.8

 
6.3

 
5.3

 
7.4

Additional benefit costs (d)
0.1

 
10.2

 
—

 
—

 
—

 
—

Settlement losses (e)
5.4

 
1.1

 
1.4

 
—

 
—

 
—

 

$35.4

 

$32.7

 

$28.2

 

$3.9

 

$6.7

 

$21.6

IPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$7.5

 

$6.1

 

$6.2

 

$3.0

 

$2.6

 

$3.4

Interest cost
17.1

 
16.7

 
16.5

 
4.4

 
5.5

 
6.8

Expected return on plan assets (b)
(23.0
)
 
(20.0
)
 
(19.5
)
 
(5.1
)
 
(5.4
)
 
(5.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Transition obligation
—

 
—

 
—

 
—

 
—

 
0.1

Prior service cost (credit)
0.4

 
0.5

 
0.6

 
(6.3
)
 
(5.0
)
 
(1.1
)
Actuarial loss
10.2

 
5.7

 
7.2

 
3.5

 
2.9

 
4.0

 

$12.2

 

$9.0

 

$11.0

 

($0.5
)
 

$0.6

 

$7.9

WPL
Qualified Defined Benefit Pension Plan
 
Other Postretirement Benefits Plans (a)
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Service cost

$5.2

 

$4.5

 

$4.9

 

$2.7

 

$2.9

 

$3.6

Interest cost
16.4

 
16.1

 
15.7

 
4.1

 
4.9

 
5.5

Expected return on plan assets (b)
(22.3
)
 
(20.0
)
 
(19.1
)
 
(1.3
)
 
(1.3
)
 
(1.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Prior service cost (credit)
0.5

 
0.5

 
0.5

 
(3.9
)
 
(3.4
)
 
(0.7
)
Actuarial loss
12.1

 
7.1

 
8.5

 
2.3

 
2.1

 
2.5

Additional benefit costs
0.1

 
—

 
—

 
—

 
—

 
—

 

$12.0

 

$8.2

 

$10.5

 

$3.9

 

$5.2

 

$9.6

Directly assigned defined benefit pension plans
IPL
 
WPL
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Interest cost

$7.0

 

$7.3

 

$7.8

 

$5.2

 

$5.5

 

$5.6

Expected return on plan assets (b)
(9.6
)
 
(9.7
)
 
(9.7
)
 
(7.3
)
 
(7.3
)
 
(7.3
)
Amortization of (c):
 
 
 
 
 
 
 
 
 
 
 
Prior service credit
(0.2
)
 
(0.2
)
 
(0.3
)
 
(0.1
)
 
(0.2
)
 
(0.2
)
Actuarial loss
3.9

 
3.0

 
2.9

 
3.6

 
3.0

 
2.8

Additional benefit costs (d)
—

 
2.8

 
—

 
—

 
0.7

 
—

 

$1.1

 

$3.2

 

$0.7

 

$1.4

 

$1.7

 

$0.9


(a)
In 2011, Alliant Energy, IPL and WPL amended their defined benefit postretirement health care plans resulting in a revision to the method and level of coverage provided for participants more than 65 years of age. This amendment was determined to be a significant event, which required Alliant Energy, IPL and WPL to remeasure their defined benefit postretirement health care plans in 2011. The amendment resulted in a decrease in Alliant Energy’s, IPL’s and WPL’s postretirement benefit obligations of $55 million, $30 million and $16 million, respectively, in 2011 with the impact of the remeasurement on net periodic benefit costs being recognized prospectively from the remeasurement date. The impact of the remeasurement decreased Alliant Energy’s, IPL’s and WPL’s net periodic benefit costs by $11.3 million, $7.2 million, and $3.8 million in 2011, respectively. The discount rate used for the remeasurement was 5.20%. All other assumptions used for the remeasurement were consistent with the measurement assumptions used at December 31, 2010.
(b)
The expected return on plan assets is based on the expected rate of return on plan assets and the fair value approach to the market-related value of plan assets.
(c)
Unrecognized net actuarial gains or losses in excess of 10% of the greater of the plans’ benefit obligations or assets are amortized over the average future service lives of plan participants, except for the Alliant Energy Cash Balance Pension Plan (Cash Balance Plan) where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits. Unrecognized prior service costs (credits) for the postretirement benefits plans are amortized over the average future service period to full eligibility of the participants of each plan.
(d)
Alliant Energy reached an agreement with the IRS, which resulted in a favorable determination letter for the Cash Balance Plan in 2011. The agreement with the IRS required Alliant Energy to amend the Cash Balance Plan, which was completed in 2011 resulting in aggregate additional benefits of $10.2 million paid by Alliant Energy to certain former participants in the Cash Balance Plan in 2011. Alliant Energy recognized $10.2 million of additional benefits costs in 2011 related to these benefits. IPL recognized $6.3 million ($2.8 million directly assigned and $3.5 million allocated by Corporate Services) and WPL recognized $3.4 million ($0.7 million directly assigned and $2.7 million allocated by Corporate Services) of additional benefits costs in 2011 related to these benefits. Refer to Note 13(c) for additional information regarding the Cash Balance Plan.
(e)
Settlement losses related to payments made to retired executives of Alliant Energy.
Schedule Of Qualified And Non-Qualified Pension And Other Postretirement Benefits Costs
The following table includes the allocated qualified and non-qualified pension and other postretirement benefits costs associated with Corporate Services employees providing services to IPL and WPL (in millions):
 
Pension Benefits Costs (a)
 
Other Postretirement Benefits Costs
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
IPL

$4.9

 

$5.8

 

$2.9

 

$0.1

 

$0.3

 

$2.0

WPL
3.6

 
4.2

 
1.9

 
0.1

 
0.2

 
1.3


(a)
Includes settlement losses related to payments made to retired executives of Alliant Energy in 2012. In 2011, additional qualified pension benefits costs resulting from the 2011 amendment to the Cash Balance Plan allocated to IPL and WPL by Corporate Services were $3.5 million and $2.7 million, respectively.
Estimated Amortization From Regulatory Assets And Regulatory Liabilities On The Consolidated Balance Sheets And Accumulated Other Comprehensive Loss On Alliant Energy's Consolidated Balance Sheet Into Net Periodic Benefit Cost
The estimated amortization from “Regulatory assets” and “Regulatory liabilities” on the Consolidated Balance Sheets and AOCL on Alliant Energy’s Consolidated Balance Sheet into net periodic benefit cost in 2013 is as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
 
 
Other
 
Qualified
 
Other
 
Qualified
 
Other
 
Defined Benefit
 
Postretirement
 
Defined Benefit
 
Postretirement
 
Defined Benefit
 
Postretirement
 
Pension Plans
 
Benefits Plans
 
Pension Plan
 
Benefits Plans
 
Pension Plan
 
Benefits Plans
Actuarial loss

$36.2

 

$4.9

 

$10.9

 

$2.7

 

$13.2

 

$1.9

Prior service cost (credit)
0.2

 
(11.9
)
 
0.4

 
(6.3
)
 
0.5

 
(3.9
)
 

$36.4

 

($7.0
)
 

$11.3

 

($3.6
)
 

$13.7

 

($2.0
)
Directly assigned defined benefit pension plans
IPL
 
WPL
Actuarial loss

$4.2

 

$3.9

Prior service credit
(0.2
)
 
(0.2
)
 

$4.0

 

$3.7
Funded Status Of Benefit Plans
A reconciliation of the funded status of WPL’s sponsored qualified defined benefit pension and other postretirement benefits plans to the amounts recognized on WPL’s Consolidated Balance Sheets, at December 31 was as follows (in millions):
WPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Change in projected benefit obligation:
 
 
 
 
 
 
 
Net projected benefit obligation at January 1

$332.5

 

$283.3

 

$89.6

 

$103.3

Service cost
5.2

 
4.5

 
2.7

 
2.9

Interest cost
16.4

 
16.1

 
4.1

 
4.9

Plan participants’ contributions
—

 
—

 
1.2

 
3.3

Plan amendments (a)
—

 
—

 
—

 
(18.2
)
Additional benefit costs
0.1

 
—

 
—

 
—

Actuarial loss
43.4

 
43.3

 
0.3

 
2.3

ERRP proceeds
—

 
—

 
—

 
0.2

Gross benefits paid
(17.4
)
 
(14.7
)
 
(8.8
)
 
(9.6
)
Federal subsidy on other postretirement benefits paid
—

 
—

 
—

 
0.5

Net projected benefit obligation at December 31
380.2

 
332.5

 
89.1

 
89.6

Change in plan assets:
 
 
 
 
 
 
 
Fair value of plan assets at January 1
289.6

 
255.2

 
25.1

 
25.0

Actual return on plan assets
41.0

 
9.1

 
2.5

 
0.9

Employer contributions
—

 
40.0

 
2.3

 
5.5

Plan participants’ contributions
—

 
—

 
1.2

 
3.3

Gross benefits paid
(17.4
)
 
(14.7
)
 
(8.8
)
 
(9.6
)
Fair value of plan assets at December 31
313.2

 
289.6

 
22.3

 
25.1

Under funded status at December 31

($67.0
)
 

($42.9
)
 

($66.8
)
 

($64.5
)

WPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Amounts recognized on the Consolidated Balance Sheets consist of:
 
 
 
 
 
 
 
Non-current assets

$—

 

$—

 

$3.5

 

$1.3

Other current liabilities
—

 
—

 
(2.8
)
 
—

Pension and other benefit obligations
(67.0
)
 
(42.9
)
 
(67.5
)
 
(65.8
)
Net amount recognized at December 31

($67.0
)
 

($42.9
)
 

($66.8
)
 

($64.5
)
Amounts recognized in Regulatory Assets and Regulatory Liabilities consist of (b):
 
 
 
 
 
 
 
Net actuarial loss

$155.3

 

$142.7

 

$24.3

 

$27.8

Prior service cost (credit)
1.9

 
2.4

 
(13.4
)
 
(17.3
)
 

$157.2

 

$145.1

 

$10.9

 

$10.5


(a)
Refer to “Net Periodic Benefit Costs” above for additional information regarding plan amendments to the defined benefit pension and other postretirement benefits plans in 2011.
(b)
Refer to Note 1(b) for amounts recognized in “Regulatory assets” on WPL’s Consolidated Balance Sheets. At December 31, 2012 and 2011, $0.2 million and $0, respectively, of regulatory liabilities were recognized related to WPL’s other postretirement benefits plans.
Accumulated Benefit Obligations
Included in the following tables are accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and other postretirement benefits plans with accumulated benefit obligations in excess of plan assets, as well as defined benefit pension plans with projected benefit obligations in excess of plan assets as of the December 31 measurement date (Not Applicable (N/A); in millions):
Alliant Energy
Defined Benefit
 
Other Postretirement
 
Pension Plans
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$1,155.5

 

$1,029.4

 

$223.2

 

$224.2

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
1,155.5

 
1,029.4

 
223.2

 
224.2

Fair value of plan assets
965.6

 
897.4

 
123.1

 
120.4

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
1,207.5

 
1,081.4

 
N/A

 
N/A

Fair value of plan assets
965.6

 
897.4

 
N/A

 
N/A


IPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$359.6

 

$314.6

 

$96.0

 

$97.5

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
359.6

 
314.6

 
96.0

 
97.5

Fair value of plan assets
322.3

 
298.7

 
78.8

 
74.7

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
388.4

 
344.5

 
N/A

 
N/A

Fair value of plan assets
322.3

 
298.7

 
N/A

 
N/A


WPL
Qualified Defined Benefit
 
Other Postretirement
 
Pension Plan
 
Benefits Plans
 
2012
 
2011
 
2012
 
2011
Accumulated benefit obligations

$363.7

 

$314.7

 

$89.1

 

$89.6

Plans with accumulated benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Accumulated benefit obligations
363.7

 
314.7

 
89.1

 
89.6

Fair value of plan assets
313.2

 
289.6

 
22.3

 
25.1

Plans with projected benefit obligations in excess of plan assets:
 
 
 
 
 
 
 
Projected benefit obligations
380.2

 
332.5

 
N/A

 
N/A

Fair value of plan assets
313.2

 
289.6

 
N/A

 
N/A
Regulatory Assets and Regulatory Liabilities
In addition to the amounts recognized in “Regulatory assets and regulatory liabilities” in the above tables for IPL and WPL, “Regulatory assets” and “Regulatory liabilities” were recognized for amounts associated with Corporate Services employees participating in other Alliant Energy sponsored benefit plans that were allocated to IPL and WPL at December 31 as follows (in millions):
 
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Regulatory assets

$38.1

 

$33.7

 

$25.5

 

$22.3

Regulatory liabilities
0.6

 
0.3

 
0.4

 
0.2
Estimated Future Employer Contributions
Alliant Energy, IPL and WPL estimate that funding for the qualified defined benefit pension, non-qualified defined benefit pension and other postretirement benefits plans, and the directly assigned qualified and non-qualified defined benefit pension plans amounts, during 2013 will be as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
Qualified defined benefit pension plans

$—

 

$—

 

$—

Non-qualified defined benefit pension plans (a)
2.4

 
N/A

 
N/A

Directly assigned defined benefit pension plans (b)
N/A

 
0.8

 
0.2

Other postretirement benefits plans
3.0

 
—

 
3.0


(a)
Alliant Energy sponsors several non-qualified defined benefit pension plans that cover certain current and former key employees of IPL and WPL. Alliant Energy allocates pension costs to IPL and WPL for these plans.
(b)
Amounts directly assigned to IPL and WPL for non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.
Expected Benefit Payments
Expected benefit payments, and the directly assigned qualified and non-qualified defined benefit pension benefits amounts, which reflect expected future service, as appropriate, are as follows (in millions):
Alliant Energy
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified and non-qualified defined benefit pension benefits

$61.9

 

$64.7

 

$68.5

 

$66.6

 

$69.2

 

$374.1

Other postretirement benefits
16.6

 
16.2

 
16.3

 
16.4

 
16.6

 
84.2

 

$78.5

 

$80.9

 

$84.8

 

$83.0

 

$85.8

 

$458.3

IPL
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified defined benefit pension benefits

$15.9

 

$16.9

 

$17.9

 

$18.9

 

$20.0

 

$116.0

Directly assigned defined benefit pension benefits
12.6

 
13.4

 
14.1

 
12.1

 
13.5

 
60.2

Other postretirement benefits
8.0

 
7.3

 
7.2

 
7.1

 
7.2

 
35.9

 

$36.5

 

$37.6

 

$39.2

 

$38.1

 

$40.7

 

$212.1

WPL
2013
 
2014
 
2015
 
2016
 
2017
 
2018 - 2022
Qualified defined benefit pension benefits

$14.4

 

$15.2

 

$16.1

 

$17.0

 

$18.0

 

$108.7

Directly assigned defined benefit pension benefits
10.5

 
10.2

 
11.4

 
9.8

 
9.5

 
43.0

Other postretirement benefits
6.3

 
6.5

 
6.7

 
6.7

 
6.8

 
34.3

 

$31.2

 

$31.9

 

$34.2

 

$33.5

 

$34.3

 

$186.0
Plan Assets And Plan Assets Percentage Associated With Entity's Benefit Plans
At December 31, the fair values of IPL’s and WPL’s qualified and non-qualified defined benefit pension plan assets associated with IPL’s and WPL’s current and former non-bargaining employees who are participants in Alliant Energy and Corporate Services sponsored plans that were directly assigned to IPL and WPL, along with the percentage these assets represent of the fair values by asset category and fair value hierarchy level shown in the above table were as follows (dollars in millions):
 
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Fair values of directly assigned amounts
$136.5
 
$127.4
 
$102.2
 
$97.0
Percentage represented
14.1%
 
14.2%
 
10.6%
 
10.8%
Recognized Compensation Expense And Income Tax Benefits
A summary of compensation expense (allocated to IPL and WPL) and the related income tax benefits recognized for share-based compensation awards was as follows (in millions):
 
Alliant Energy
 
IPL
 
WPL
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
 
2012
 
2011
 
2010
Compensation expense

$6.9

 

$10.1

 

$7.5

 

$3.6

 

$5.5

 

$4.0

 

$3.0

 

$4.1

 

$3.0

Income tax benefits
2.8

 
4.0

 
3.0

 
1.5

 
2.2

 
1.6

 
1.2

 
1.7

 
1.2
Directly Assigned Defined Pension Benefits [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Funded Status Of Benefit Plans
A reconciliation of the funded status of the directly assigned qualified and non-qualified defined benefit pension plans to the amounts recognized on IPL’s and WPL’s Consolidated Balance Sheets at December 31 was as follows (in millions):
Directly assigned defined benefit pension plans
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Change in projected benefit obligation:
 
 
 
 
 
 
 
Net projected benefit obligation at January 1

$155.4

 

$144.4

 

$115.2

 

$107.4

Interest cost
7.0

 
7.3

 
5.2

 
5.5

Plan amendments
—

 
2.8

 
—

 
0.7

Actuarial loss
17.9

 
13.2

 
14.5

 
10.3

Gross benefits paid
(9.5
)
 
(12.3
)
 
(8.4
)
 
(8.7
)
Net projected benefit obligation at December 31
170.8

 
155.4

 
126.5

 
115.2

Change in plan assets:
 
 
 
 
 
 
 
Fair value of plan assets at January 1
127.4

 
127.6

 
97.0

 
95.6

Actual return on plan assets
17.9

 
4.2

 
13.5

 
3.2

Employer contributions
0.7

 
7.9

 
0.1

 
6.9

Gross benefits paid
(9.5
)
 
(12.3
)
 
(8.4
)
 
(8.7
)
Fair value of plan assets at December 31
136.5

 
127.4

 
102.2

 
97.0

Under funded status at December 31

($34.3
)
 

($28.0
)
 

($24.3
)
 

($18.2
)
Directly assigned defined benefit pension plans
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Amounts recognized on the Consolidated Balance Sheets consist of:
 
 
 
 
 
 
 
Other current liabilities

($0.8
)
 

($0.8
)
 

($0.2
)
 

($0.2
)
Pension and other benefit obligations
(33.5
)
 
(27.2
)
 
(24.1
)
 
(18.0
)
Net amount recognized at December 31

($34.3
)
 

($28.0
)
 

($24.3
)
 

($18.2
)
Amounts recognized in Regulatory Assets (a):
 
 
 
 
 
 
 
Net actuarial loss

$81.9

 

$76.2

 

$78.4

 

$73.7

Prior service credit
(3.2
)
 
(3.4
)
 
(2.3
)
 
(2.4
)
 

$78.7

 

$72.8

 

$76.1

 

$71.3

Accumulated benefit obligations

$170.8

 

$155.4

 

$126.5

 

$115.2


(a)
Refer to Note 1(b) for amounts recognized in “Regulatory assets” on IPL’s and WPL’s Consolidated Balance Sheets.
Directly Assigned Defined Pension Benefits [Member] | IPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Funded Status Of Benefit Plans
A reconciliation of the funded status of the directly assigned qualified and non-qualified defined benefit pension plans to the amounts recognized on IPL’s and WPL’s Consolidated Balance Sheets at December 31 was as follows (in millions):
Directly assigned defined benefit pension plans
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Change in projected benefit obligation:
 
 
 
 
 
 
 
Net projected benefit obligation at January 1

$155.4

 

$144.4

 

$115.2

 

$107.4

Interest cost
7.0

 
7.3

 
5.2

 
5.5

Plan amendments
—

 
2.8

 
—

 
0.7

Actuarial loss
17.9

 
13.2

 
14.5

 
10.3

Gross benefits paid
(9.5
)
 
(12.3
)
 
(8.4
)
 
(8.7
)
Net projected benefit obligation at December 31
170.8

 
155.4

 
126.5

 
115.2

Change in plan assets:
 
 
 
 
 
 
 
Fair value of plan assets at January 1
127.4

 
127.6

 
97.0

 
95.6

Actual return on plan assets
17.9

 
4.2

 
13.5

 
3.2

Employer contributions
0.7

 
7.9

 
0.1

 
6.9

Gross benefits paid
(9.5
)
 
(12.3
)
 
(8.4
)
 
(8.7
)
Fair value of plan assets at December 31
136.5

 
127.4

 
102.2

 
97.0

Under funded status at December 31

($34.3
)
 

($28.0
)
 

($24.3
)
 

($18.2
)
Directly assigned defined benefit pension plans
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Amounts recognized on the Consolidated Balance Sheets consist of:
 
 
 
 
 
 
 
Other current liabilities

($0.8
)
 

($0.8
)
 

($0.2
)
 

($0.2
)
Pension and other benefit obligations
(33.5
)
 
(27.2
)
 
(24.1
)
 
(18.0
)
Net amount recognized at December 31

($34.3
)
 

($28.0
)
 

($24.3
)
 

($18.2
)
Amounts recognized in Regulatory Assets (a):
 
 
 
 
 
 
 
Net actuarial loss

$81.9

 

$76.2

 

$78.4

 

$73.7

Prior service credit
(3.2
)
 
(3.4
)
 
(2.3
)
 
(2.4
)
 

$78.7

 

$72.8

 

$76.1

 

$71.3

Accumulated benefit obligations

$170.8

 

$155.4

 

$126.5

 

$115.2


(a)
Refer to Note 1(b) for amounts recognized in “Regulatory assets” on IPL’s and WPL’s Consolidated Balance Sheets.
Directly Assigned Defined Pension Benefits [Member] | WPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Funded Status Of Benefit Plans
A reconciliation of the funded status of the directly assigned qualified and non-qualified defined benefit pension plans to the amounts recognized on IPL’s and WPL’s Consolidated Balance Sheets at December 31 was as follows (in millions):
Directly assigned defined benefit pension plans
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Change in projected benefit obligation:
 
 
 
 
 
 
 
Net projected benefit obligation at January 1

$155.4

 

$144.4

 

$115.2

 

$107.4

Interest cost
7.0

 
7.3

 
5.2

 
5.5

Plan amendments
—

 
2.8

 
—

 
0.7

Actuarial loss
17.9

 
13.2

 
14.5

 
10.3

Gross benefits paid
(9.5
)
 
(12.3
)
 
(8.4
)
 
(8.7
)
Net projected benefit obligation at December 31
170.8

 
155.4

 
126.5

 
115.2

Change in plan assets:
 
 
 
 
 
 
 
Fair value of plan assets at January 1
127.4

 
127.6

 
97.0

 
95.6

Actual return on plan assets
17.9

 
4.2

 
13.5

 
3.2

Employer contributions
0.7

 
7.9

 
0.1

 
6.9

Gross benefits paid
(9.5
)
 
(12.3
)
 
(8.4
)
 
(8.7
)
Fair value of plan assets at December 31
136.5

 
127.4

 
102.2

 
97.0

Under funded status at December 31

($34.3
)
 

($28.0
)
 

($24.3
)
 

($18.2
)
Directly assigned defined benefit pension plans
IPL
 
WPL
 
2012
 
2011
 
2012
 
2011
Amounts recognized on the Consolidated Balance Sheets consist of:
 
 
 
 
 
 
 
Other current liabilities

($0.8
)
 

($0.8
)
 

($0.2
)
 

($0.2
)
Pension and other benefit obligations
(33.5
)
 
(27.2
)
 
(24.1
)
 
(18.0
)
Net amount recognized at December 31

($34.3
)
 

($28.0
)
 

($24.3
)
 

($18.2
)
Amounts recognized in Regulatory Assets (a):
 
 
 
 
 
 
 
Net actuarial loss

$81.9

 

$76.2

 

$78.4

 

$73.7

Prior service credit
(3.2
)
 
(3.4
)
 
(2.3
)
 
(2.4
)
 

$78.7

 

$72.8

 

$76.1

 

$71.3

Accumulated benefit obligations

$170.8

 

$155.4

 

$126.5

 

$115.2


(a)
Refer to Note 1(b) for amounts recognized in “Regulatory assets” on IPL’s and WPL’s Consolidated Balance Sheets.
Pension Plans, Defined Benefit [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Fair Value Of Plan Assets By Asset Category And Fair Value Hierarchy Level
At December 31, the fair values of Alliant Energy’s qualified and non-qualified defined benefit pension plans assets by asset category and fair value hierarchy level were as follows (in millions):
Alliant Energy
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$43.9

 

$—

 

$43.9

 

$—

 

$117.5

 

$117.5

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. large cap core
129.0

 
129.0

 
—

 
—

 
110.7

 
110.7

 
—

 
—

U.S. large cap value
107.9

 
—

 
107.9

 
—

 
91.6

 
—

 
91.6

 
—

U.S. large cap growth
105.8

 
—

 
105.8

 
—

 
91.5

 
—

 
91.5

 
—

U.S. small cap value
30.4

 
—

 
30.4

 
—

 
25.7

 
—

 
25.7

 
—

U.S. small cap growth
25.0

 
25.0

 
—

 
—

 
21.7

 
21.7

 
—

 
—

International - developed markets
153.7

 
80.3

 
73.4

 
—

 
126.4

 
65.4

 
61.0

 
—

International - emerging markets
38.5

 
38.5

 
—

 
—

 
30.4

 
30.4

 
—

 
—

Global asset allocation securities
94.5

 
56.3

 
38.2

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
30.7

 
—

 
30.7

 
—

 
57.1

 
—

 
57.1

 
—

Government and agency obligations
49.2

 
—

 
49.2

 
—

 
87.8

 
—

 
87.8

 
—

Fixed income funds
162.6

 
0.2

 
162.4

 
—

 
146.7

 
0.2

 
146.5

 
—

Securities lending invested collateral
4.4

 
—

 
2.9

 
1.5

 
9.3

 
4.7

 
2.8

 
1.8

 
975.6

 

$329.3

 

$644.8

 

$1.5

 
916.4

 

$350.6

 

$564.0

 

$1.8

Accrued investment income
0.6

 
 
 
 
 
 
 
1.0

 
 
 
 
 
 
Due to brokers, net (pending trades with brokers)
(1.5
)
 
 
 
 
 
 
 
(4.7
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(9.1
)
 
 
 
 
 
 
 
(15.3
)
 
 
 
 
 
 
Total pension plan assets

$965.6

 
 
 
 
 
 
 

$897.4

 
 
 
 
 
 

At December 31, 2012, the current target ranges and actual allocations for Alliant Energy’s, IPL’s and WPL’s defined benefit pension plan assets were as follows:
 
Target Range
 
Actual
 
Allocation
 
Allocation
Cash and equivalents
—
%
-
5%
 
4%
Equity securities:
 
 
 
 
 
U.S. large cap core
10
%
-
20%
 
13%
U.S. large cap value
6
%
-
16%
 
11%
U.S. large cap growth
6
%
-
16%
 
11%
U.S. small cap value
—
%
-
6%
 
3%
U.S. small cap growth
—
%
-
6%
 
3%
International - developed markets
11
%
-
23%
 
16%
International - emerging markets
—
%
-
8%
 
4%
Global asset allocation securities
5
%
-
15%
 
10%
Fixed income securities
15
%
-
35%
 
25%
Pension Plans, Defined Benefit [Member] | IPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Fair Value Of Plan Assets By Asset Category And Fair Value Hierarchy Level
At December 31, the fair values of IPL’s qualified defined benefit pension plan assets by asset category and fair value hierarchy level were as follows (in millions):
IPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$14.6

 

$—

 

$14.6

 

$—

 

$39.1

 

$39.1

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. large cap core
43.1

 
43.1

 
—

 
—

 
36.8

 
36.8

 
—

 
—

U.S. large cap value
36.0

 
—

 
36.0

 
—

 
30.5

 
—

 
30.5

 
—

U.S. large cap growth
35.3

 
—

 
35.3

 
—

 
30.5

 
—

 
30.5

 
—

U.S. small cap value
10.2

 
—

 
10.2

 
—

 
8.6

 
—

 
8.6

 
—

U.S. small cap growth
8.3

 
8.3

 
—

 
—

 
7.2

 
7.2

 
—

 
—

International - developed markets
51.3

 
26.8

 
24.5

 
—

 
42.1

 
21.8

 
20.3

 
—

International - emerging markets
12.9

 
12.9

 
—

 
—

 
10.1

 
10.1

 
—

 
—

Global asset allocation securities
31.5

 
18.8

 
12.7

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
10.2

 
—

 
10.2

 
—

 
19.0

 
—

 
19.0

 
—

Government and agency obligations
16.4

 
—

 
16.4

 
—

 
29.2

 
—

 
29.2

 
—

Fixed income funds
54.3

 
0.1

 
54.2

 
—

 
48.8

 
0.1

 
48.7

 
—

Securities lending invested collateral
1.5

 
—

 
1.0

 
0.5

 
3.1

 
1.6

 
0.9

 
0.6

 
325.6

 

$110.0

 

$215.1

 

$0.5

 
305.0

 

$116.7

 

$187.7

 

$0.6

Accrued investment income
0.2

 
 
 
 
 
 
 
0.4

 
 
 
 
 
 
Due to brokers, net (pending trades with brokers)
(0.5
)
 
 
 
 
 
 
 
(1.6
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(3.0
)
 
 
 
 
 
 
 
(5.1
)
 
 
 
 
 
 
Total pension plan assets

$322.3

 
 
 
 
 
 
 

$298.7

 
 
 
 
 
 

At December 31, 2012, the current target ranges and actual allocations for Alliant Energy’s, IPL’s and WPL’s defined benefit pension plan assets were as follows:
 
Target Range
 
Actual
 
Allocation
 
Allocation
Cash and equivalents
—
%
-
5%
 
4%
Equity securities:
 
 
 
 
 
U.S. large cap core
10
%
-
20%
 
13%
U.S. large cap value
6
%
-
16%
 
11%
U.S. large cap growth
6
%
-
16%
 
11%
U.S. small cap value
—
%
-
6%
 
3%
U.S. small cap growth
—
%
-
6%
 
3%
International - developed markets
11
%
-
23%
 
16%
International - emerging markets
—
%
-
8%
 
4%
Global asset allocation securities
5
%
-
15%
 
10%
Fixed income securities
15
%
-
35%
 
25%
Pension Plans, Defined Benefit [Member] | WPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Fair Value Of Plan Assets By Asset Category And Fair Value Hierarchy Level
At December 31, 2012, the current target ranges and actual allocations for Alliant Energy’s, IPL’s and WPL’s defined benefit pension plan assets were as follows:
 
Target Range
 
Actual
 
Allocation
 
Allocation
Cash and equivalents
—
%
-
5%
 
4%
Equity securities:
 
 
 
 
 
U.S. large cap core
10
%
-
20%
 
13%
U.S. large cap value
6
%
-
16%
 
11%
U.S. large cap growth
6
%
-
16%
 
11%
U.S. small cap value
—
%
-
6%
 
3%
U.S. small cap growth
—
%
-
6%
 
3%
International - developed markets
11
%
-
23%
 
16%
International - emerging markets
—
%
-
8%
 
4%
Global asset allocation securities
5
%
-
15%
 
10%
Fixed income securities
15
%
-
35%
 
25%
At December 31, the fair values of WPL’s qualified defined benefit pension plan assets by asset category and fair value hierarchy level were as follows (in millions):
WPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$14.2

 

$—

 

$14.2

 

$—

 

$37.9

 

$37.9

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. large cap core
41.8

 
41.8

 
—

 
—

 
35.7

 
35.7

 
—

 
—

U.S. large cap value
35.0

 
—

 
35.0

 
—

 
29.6

 
—

 
29.6

 
—

U.S. large cap growth
34.3

 
—

 
34.3

 
—

 
29.5

 
—

 
29.5

 
—

U.S. small cap value
9.9

 
—

 
9.9

 
—

 
8.3

 
—

 
8.3

 
—

U.S. small cap growth
8.1

 
8.1

 
—

 
—

 
7.0

 
7.0

 
—

 
—

International - developed markets
49.9

 
26.1

 
23.8

 
—

 
40.8

 
21.1

 
19.7

 
—

International - emerging markets
12.5

 
12.5

 
—

 
—

 
9.8

 
9.8

 
—

 
—

Global asset allocation securities
30.7

 
18.3

 
12.4

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
9.9

 
—

 
9.9

 
—

 
18.4

 
—

 
18.4

 
—

Government and agency obligations
16.0

 
—

 
16.0

 
—

 
28.3

 
—

 
28.3

 
—

Fixed income funds
52.8

 
0.1

 
52.7

 
—

 
47.4

 
0.1

 
47.3

 
—

Securities lending invested collateral
1.4

 
—

 
0.9

 
0.5

 
3.0

 
1.5

 
0.9

 
0.6

 
316.5

 

$106.9

 

$209.1

 

$0.5

 
295.7

 

$113.1

 

$182.0

 

$0.6

Accrued investment income
0.2

 
 
 
 
 
 
 
0.3

 
 
 
 
 
 
Due to brokers, net (pending trades with brokers)
(0.5
)
 
 
 
 
 
 
 
(1.5
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(3.0
)
 
 
 
 
 
 
 
(4.9
)
 
 
 
 
 
 
Total pension plan assets

$313.2

 
 
 
 
 
 
 

$289.6

 
 
 
 
 
 
Defined Contribution Plans [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Employees Participate In Defined Contribution Retirement Plans
Costs related to the 401(k) savings plans, which are partially based on the participants’ level of contribution, were as follows (in millions):
 
Alliant Energy
 
IPL (a)
 
WPL (a)
 
2012
 
2011
 
2010
 
2012

 
2011

 
2010

 
2012
 
2011
 
2010
401(k) costs

$18.5

 

$18.4

 

$18.5

 

$9.6

 

$9.2

 

$8.8

 

$8.1

 

$8.4

 

$8.9


(a)
IPL’s and WPL’s amounts include allocated costs associated with Corporate Services employees.
Defined Contribution Plans [Member] | IPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Employees Participate In Defined Contribution Retirement Plans
Costs related to the 401(k) savings plans, which are partially based on the participants’ level of contribution, were as follows (in millions):
 
Alliant Energy
 
IPL (a)
 
WPL (a)
 
2012
 
2011
 
2010
 
2012

 
2011

 
2010

 
2012
 
2011
 
2010
401(k) costs

$18.5

 

$18.4

 

$18.5

 

$9.6

 

$9.2

 

$8.8

 

$8.1

 

$8.4

 

$8.9


(a)
IPL’s and WPL’s amounts include allocated costs associated with Corporate Services employees.
Defined Contribution Plans [Member] | WPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Employees Participate In Defined Contribution Retirement Plans
Costs related to the 401(k) savings plans, which are partially based on the participants’ level of contribution, were as follows (in millions):
 
Alliant Energy
 
IPL (a)
 
WPL (a)
 
2012
 
2011
 
2010
 
2012

 
2011

 
2010

 
2012
 
2011
 
2010
401(k) costs

$18.5

 

$18.4

 

$18.5

 

$9.6

 

$9.2

 

$8.8

 

$8.1

 

$8.4

 

$8.9


(a)
IPL’s and WPL’s amounts include allocated costs associated with Corporate Services employees.
Other Postretirement Benefits Plans [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Fair Value Of Plan Assets By Asset Category And Fair Value Hierarchy Level
At December 31, 2012, the current target ranges and actual allocations for Alliant Energy’s, IPL’s and WPL’s VEBA trusts with assets greater than $5 million were as follows:
 
Target Range
 
Actual
 
Allocation
 
Allocation
Cash and equivalents
—
%
-
5%
 
2%
Equity securities:
 
 
 
 
 
Domestic
25
%
-
45%
 
34%
International
10
%
-
20%
 
15%
Global asset allocation securities
20
%
-
40%
 
29%
Fixed income securities
10
%
-
30%
 
20%
At December 31, the fair values of other postretirement benefits plans assets by asset category and fair value hierarchy level were as follows (in millions):
Alliant Energy
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$8.4

 

$—

 

$8.4

 

$—

 

$14.0

 

$14.0

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
32.9

 
32.9

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
2.8

 
2.8

 
—

 
—

 
37.1

 
37.1

 
—

 
—

U.S. large cap value
2.4

 
—

 
2.4

 
—

 
2.4

 
—

 
2.4

 
—

U.S. large cap growth
2.3

 
—

 
2.3

 
—

 
2.4

 
—

 
2.4

 
—

U.S. mid cap core
—

 
—

 
—

 
—

 
17.8

 
17.8

 
—

 
—

U.S. small cap core
—

 
—

 
—

 
—

 
4.7

 
4.7

 
—

 
—

U.S. small cap value
0.7

 
—

 
0.7

 
—

 
0.6

 
—

 
0.6

 
—

U.S. small cap growth
0.6

 
0.6

 
—

 
—

 
0.5

 
0.5

 
—

 
—

International - blend
14.3

 
14.3

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
3.4

 
1.8

 
1.6

 
—

 
3.3

 
1.7

 
1.6

 
—

International - emerging markets
0.8

 
0.8

 
—

 
—

 
0.8

 
0.8

 
—

 
—

Global asset allocation securities
30.4

 
29.6

 
0.8

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.7

 
—

 
0.7

 
—

 
6.1

 
—

 
6.1

 
—

Government and agency obligations
1.1

 
—

 
1.1

 
—

 
5.6

 
—

 
5.6

 
—

Fixed income funds
22.4

 
18.8

 
3.6

 
—

 
25.4

 
21.6

 
3.8

 
—

Securities lending invested collateral
0.1

 
—

 
0.1

 
—

 
0.4

 
0.2

 
0.1

 
0.1

 
123.3

 

$101.6

 

$21.7

 

$—

 
121.1

 

$98.4

 

$22.6

 

$0.1

Accrued investment income
—

 
 
 
 
 
 
 
0.1

 
 
 
 
 
 
Due to brokers, net (pending trades with brokers)
—

 
 
 
 
 
 
 
(0.2
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(0.2
)
 
 
 
 
 
 
 
(0.6
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$123.1

 
 
 
 
 
 
 

$120.4

 
 
 
 
 
 
IPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$3.3

 

$—

 

$3.3

 

$—

 

$2.1

 

$2.1

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
24.3

 
24.3

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
0.8

 
0.8

 
—

 
—

 
29.3

 
29.3

 
—

 
—

U.S. large cap value
0.7

 
—

 
0.7

 
—

 
0.8

 
—

 
0.8

 
—

U.S. large cap growth
0.7

 
—

 
0.7

 
—

 
0.8

 
—

 
0.8

 
—

U.S. mid cap core
—

 
—

 
—

 
—

 
14.7

 
14.7

 
—

 
—

U.S. small cap value
0.2

 
—

 
0.2

 
—

 
0.2

 
—

 
0.2

 
—

U.S. small cap growth
0.2

 
0.2

 
—

 
—

 
0.2

 
0.2

 
—

 
—

International - blend
10.6

 
10.6

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
1.0

 
0.5

 
0.5

 
—

 
1.2

 
0.6

 
0.6

 
—

International - emerging markets
0.2

 
0.2

 
—

 
—

 
0.3

 
0.3

 
—

 
—

Global asset allocation securities
21.5

 
21.3

 
0.2

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.2

 
—

 
0.2

 
—

 
4.6

 
—

 
4.6

 
—

Government and agency obligations
0.3

 
—

 
0.3

 
—

 
4.1

 
—

 
4.1

 
—

Fixed income funds
14.9

 
13.9

 
1.0

 
—

 
16.5

 
15.1

 
1.4

 
—

Securities lending invested collateral
—

 
—

 
—

 
—

 
0.2

 
0.1

 
0.1

 
—

 
78.9

 

$71.8

 

$7.1

 

$—

 
75.0

 

$62.4

 

$12.6

 

$—

Accrued investment income
—

 
 
 
 
 
 
 
0.1

 
 
 
 
 
 
Due to borrowers for securities lending program
(0.1
)
 
 
 
 
 
 
 
(0.4
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$78.8

 
 
 
 
 
 
 

$74.7

 
 
 
 
 
 

WPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$3.9

 

$—

 

$3.9

 

$—

 

$10.5

 

$10.5

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
3.1

 
3.1

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
1.3

 
1.3

 
—

 
—

 
1.2

 
1.2

 
—

 
—

U.S. large cap value
1.2

 
—

 
1.2

 
—

 
1.0

 
—

 
1.0

 
—

U.S. large cap growth
1.1

 
—

 
1.1

 
—

 
1.0

 
—

 
1.0

 
—

U.S. small cap core
—

 
—

 
—

 
—

 
4.7

 
4.7

 
—

 
—

U.S. small cap value
0.3

 
—

 
0.3

 
—

 
0.3

 
—

 
0.3

 
—

U.S. small cap growth
0.3

 
0.3

 
—

 
—

 
0.2

 
0.2

 
—

 
—

International - blend
1.3

 
1.3

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
1.6

 
0.8

 
0.8

 
—

 
1.3

 
0.7

 
0.6

 
—

International - emerging markets
0.4

 
0.4

 
—

 
—

 
0.3

 
0.3

 
—

 
—

Global asset allocation securities
3.6

 
3.2

 
0.4

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.3

 
—

 
0.3

 
—

 
1.1

 
—

 
1.1

 
—

Government and agency obligations
0.5

 
—

 
0.5

 
—

 
1.0

 
—

 
1.0

 
—

Fixed income funds
3.5

 
1.8

 
1.7

 
—

 
2.6

 
1.0

 
1.6

 
—

Securities lending invested collateral
—

 
—

 
—

 
—

 
0.1

 
0.1

 
—

 
—

 
22.4

 

$12.2

 

$10.2

 

$—

 
25.3

 

$18.7

 

$6.6

 

$—

Due to brokers, net (pending trades with brokers)
—

 
 
 
 
 
 
 
(0.1
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(0.1
)
 
 
 
 
 
 
 
(0.1
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$22.3

 
 
 
 
 
 
 

$25.1

 
 
 
 
 
 
Other Postretirement Benefits Plans [Member] | IPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Fair Value Of Plan Assets By Asset Category And Fair Value Hierarchy Level
At December 31, 2012, the current target ranges and actual allocations for Alliant Energy’s, IPL’s and WPL’s VEBA trusts with assets greater than $5 million were as follows:
 
Target Range
 
Actual
 
Allocation
 
Allocation
Cash and equivalents
—
%
-
5%
 
2%
Equity securities:
 
 
 
 
 
Domestic
25
%
-
45%
 
34%
International
10
%
-
20%
 
15%
Global asset allocation securities
20
%
-
40%
 
29%
Fixed income securities
10
%
-
30%
 
20%
At December 31, the fair values of other postretirement benefits plans assets by asset category and fair value hierarchy level were as follows (in millions):
Alliant Energy
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$8.4

 

$—

 

$8.4

 

$—

 

$14.0

 

$14.0

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
32.9

 
32.9

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
2.8

 
2.8

 
—

 
—

 
37.1

 
37.1

 
—

 
—

U.S. large cap value
2.4

 
—

 
2.4

 
—

 
2.4

 
—

 
2.4

 
—

U.S. large cap growth
2.3

 
—

 
2.3

 
—

 
2.4

 
—

 
2.4

 
—

U.S. mid cap core
—

 
—

 
—

 
—

 
17.8

 
17.8

 
—

 
—

U.S. small cap core
—

 
—

 
—

 
—

 
4.7

 
4.7

 
—

 
—

U.S. small cap value
0.7

 
—

 
0.7

 
—

 
0.6

 
—

 
0.6

 
—

U.S. small cap growth
0.6

 
0.6

 
—

 
—

 
0.5

 
0.5

 
—

 
—

International - blend
14.3

 
14.3

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
3.4

 
1.8

 
1.6

 
—

 
3.3

 
1.7

 
1.6

 
—

International - emerging markets
0.8

 
0.8

 
—

 
—

 
0.8

 
0.8

 
—

 
—

Global asset allocation securities
30.4

 
29.6

 
0.8

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.7

 
—

 
0.7

 
—

 
6.1

 
—

 
6.1

 
—

Government and agency obligations
1.1

 
—

 
1.1

 
—

 
5.6

 
—

 
5.6

 
—

Fixed income funds
22.4

 
18.8

 
3.6

 
—

 
25.4

 
21.6

 
3.8

 
—

Securities lending invested collateral
0.1

 
—

 
0.1

 
—

 
0.4

 
0.2

 
0.1

 
0.1

 
123.3

 

$101.6

 

$21.7

 

$—

 
121.1

 

$98.4

 

$22.6

 

$0.1

Accrued investment income
—

 
 
 
 
 
 
 
0.1

 
 
 
 
 
 
Due to brokers, net (pending trades with brokers)
—

 
 
 
 
 
 
 
(0.2
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(0.2
)
 
 
 
 
 
 
 
(0.6
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$123.1

 
 
 
 
 
 
 

$120.4

 
 
 
 
 
 
IPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$3.3

 

$—

 

$3.3

 

$—

 

$2.1

 

$2.1

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
24.3

 
24.3

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
0.8

 
0.8

 
—

 
—

 
29.3

 
29.3

 
—

 
—

U.S. large cap value
0.7

 
—

 
0.7

 
—

 
0.8

 
—

 
0.8

 
—

U.S. large cap growth
0.7

 
—

 
0.7

 
—

 
0.8

 
—

 
0.8

 
—

U.S. mid cap core
—

 
—

 
—

 
—

 
14.7

 
14.7

 
—

 
—

U.S. small cap value
0.2

 
—

 
0.2

 
—

 
0.2

 
—

 
0.2

 
—

U.S. small cap growth
0.2

 
0.2

 
—

 
—

 
0.2

 
0.2

 
—

 
—

International - blend
10.6

 
10.6

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
1.0

 
0.5

 
0.5

 
—

 
1.2

 
0.6

 
0.6

 
—

International - emerging markets
0.2

 
0.2

 
—

 
—

 
0.3

 
0.3

 
—

 
—

Global asset allocation securities
21.5

 
21.3

 
0.2

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.2

 
—

 
0.2

 
—

 
4.6

 
—

 
4.6

 
—

Government and agency obligations
0.3

 
—

 
0.3

 
—

 
4.1

 
—

 
4.1

 
—

Fixed income funds
14.9

 
13.9

 
1.0

 
—

 
16.5

 
15.1

 
1.4

 
—

Securities lending invested collateral
—

 
—

 
—

 
—

 
0.2

 
0.1

 
0.1

 
—

 
78.9

 

$71.8

 

$7.1

 

$—

 
75.0

 

$62.4

 

$12.6

 

$—

Accrued investment income
—

 
 
 
 
 
 
 
0.1

 
 
 
 
 
 
Due to borrowers for securities lending program
(0.1
)
 
 
 
 
 
 
 
(0.4
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$78.8

 
 
 
 
 
 
 

$74.7

 
 
 
 
 
 

WPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$3.9

 

$—

 

$3.9

 

$—

 

$10.5

 

$10.5

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
3.1

 
3.1

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
1.3

 
1.3

 
—

 
—

 
1.2

 
1.2

 
—

 
—

U.S. large cap value
1.2

 
—

 
1.2

 
—

 
1.0

 
—

 
1.0

 
—

U.S. large cap growth
1.1

 
—

 
1.1

 
—

 
1.0

 
—

 
1.0

 
—

U.S. small cap core
—

 
—

 
—

 
—

 
4.7

 
4.7

 
—

 
—

U.S. small cap value
0.3

 
—

 
0.3

 
—

 
0.3

 
—

 
0.3

 
—

U.S. small cap growth
0.3

 
0.3

 
—

 
—

 
0.2

 
0.2

 
—

 
—

International - blend
1.3

 
1.3

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
1.6

 
0.8

 
0.8

 
—

 
1.3

 
0.7

 
0.6

 
—

International - emerging markets
0.4

 
0.4

 
—

 
—

 
0.3

 
0.3

 
—

 
—

Global asset allocation securities
3.6

 
3.2

 
0.4

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.3

 
—

 
0.3

 
—

 
1.1

 
—

 
1.1

 
—

Government and agency obligations
0.5

 
—

 
0.5

 
—

 
1.0

 
—

 
1.0

 
—

Fixed income funds
3.5

 
1.8

 
1.7

 
—

 
2.6

 
1.0

 
1.6

 
—

Securities lending invested collateral
—

 
—

 
—

 
—

 
0.1

 
0.1

 
—

 
—

 
22.4

 

$12.2

 

$10.2

 

$—

 
25.3

 

$18.7

 

$6.6

 

$—

Due to brokers, net (pending trades with brokers)
—

 
 
 
 
 
 
 
(0.1
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(0.1
)
 
 
 
 
 
 
 
(0.1
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$22.3

 
 
 
 
 
 
 

$25.1

 
 
 
 
 
 
Other Postretirement Benefits Plans [Member] | WPL [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Fair Value Of Plan Assets By Asset Category And Fair Value Hierarchy Level
At December 31, the fair values of other postretirement benefits plans assets by asset category and fair value hierarchy level were as follows (in millions):
Alliant Energy
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$8.4

 

$—

 

$8.4

 

$—

 

$14.0

 

$14.0

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
32.9

 
32.9

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
2.8

 
2.8

 
—

 
—

 
37.1

 
37.1

 
—

 
—

U.S. large cap value
2.4

 
—

 
2.4

 
—

 
2.4

 
—

 
2.4

 
—

U.S. large cap growth
2.3

 
—

 
2.3

 
—

 
2.4

 
—

 
2.4

 
—

U.S. mid cap core
—

 
—

 
—

 
—

 
17.8

 
17.8

 
—

 
—

U.S. small cap core
—

 
—

 
—

 
—

 
4.7

 
4.7

 
—

 
—

U.S. small cap value
0.7

 
—

 
0.7

 
—

 
0.6

 
—

 
0.6

 
—

U.S. small cap growth
0.6

 
0.6

 
—

 
—

 
0.5

 
0.5

 
—

 
—

International - blend
14.3

 
14.3

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
3.4

 
1.8

 
1.6

 
—

 
3.3

 
1.7

 
1.6

 
—

International - emerging markets
0.8

 
0.8

 
—

 
—

 
0.8

 
0.8

 
—

 
—

Global asset allocation securities
30.4

 
29.6

 
0.8

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.7

 
—

 
0.7

 
—

 
6.1

 
—

 
6.1

 
—

Government and agency obligations
1.1

 
—

 
1.1

 
—

 
5.6

 
—

 
5.6

 
—

Fixed income funds
22.4

 
18.8

 
3.6

 
—

 
25.4

 
21.6

 
3.8

 
—

Securities lending invested collateral
0.1

 
—

 
0.1

 
—

 
0.4

 
0.2

 
0.1

 
0.1

 
123.3

 

$101.6

 

$21.7

 

$—

 
121.1

 

$98.4

 

$22.6

 

$0.1

Accrued investment income
—

 
 
 
 
 
 
 
0.1

 
 
 
 
 
 
Due to brokers, net (pending trades with brokers)
—

 
 
 
 
 
 
 
(0.2
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(0.2
)
 
 
 
 
 
 
 
(0.6
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$123.1

 
 
 
 
 
 
 

$120.4

 
 
 
 
 
 
IPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$3.3

 

$—

 

$3.3

 

$—

 

$2.1

 

$2.1

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
24.3

 
24.3

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
0.8

 
0.8

 
—

 
—

 
29.3

 
29.3

 
—

 
—

U.S. large cap value
0.7

 
—

 
0.7

 
—

 
0.8

 
—

 
0.8

 
—

U.S. large cap growth
0.7

 
—

 
0.7

 
—

 
0.8

 
—

 
0.8

 
—

U.S. mid cap core
—

 
—

 
—

 
—

 
14.7

 
14.7

 
—

 
—

U.S. small cap value
0.2

 
—

 
0.2

 
—

 
0.2

 
—

 
0.2

 
—

U.S. small cap growth
0.2

 
0.2

 
—

 
—

 
0.2

 
0.2

 
—

 
—

International - blend
10.6

 
10.6

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
1.0

 
0.5

 
0.5

 
—

 
1.2

 
0.6

 
0.6

 
—

International - emerging markets
0.2

 
0.2

 
—

 
—

 
0.3

 
0.3

 
—

 
—

Global asset allocation securities
21.5

 
21.3

 
0.2

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.2

 
—

 
0.2

 
—

 
4.6

 
—

 
4.6

 
—

Government and agency obligations
0.3

 
—

 
0.3

 
—

 
4.1

 
—

 
4.1

 
—

Fixed income funds
14.9

 
13.9

 
1.0

 
—

 
16.5

 
15.1

 
1.4

 
—

Securities lending invested collateral
—

 
—

 
—

 
—

 
0.2

 
0.1

 
0.1

 
—

 
78.9

 

$71.8

 

$7.1

 

$—

 
75.0

 

$62.4

 

$12.6

 

$—

Accrued investment income
—

 
 
 
 
 
 
 
0.1

 
 
 
 
 
 
Due to borrowers for securities lending program
(0.1
)
 
 
 
 
 
 
 
(0.4
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$78.8

 
 
 
 
 
 
 

$74.7

 
 
 
 
 
 

WPL
2012
 
2011
 
Fair
 
Level
 
Level
 
Level
 
Fair
 
Level
 
Level
 
Level
 
Value
 
1
 
2
 
3
 
Value
 
1
 
2
 
3
Cash and equivalents

$3.9

 

$—

 

$3.9

 

$—

 

$10.5

 

$10.5

 

$—

 

$—

Equity securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
U.S. blend
3.1

 
3.1

 
—

 
—

 
—

 
—

 
—

 
—

U.S. large cap core
1.3

 
1.3

 
—

 
—

 
1.2

 
1.2

 
—

 
—

U.S. large cap value
1.2

 
—

 
1.2

 
—

 
1.0

 
—

 
1.0

 
—

U.S. large cap growth
1.1

 
—

 
1.1

 
—

 
1.0

 
—

 
1.0

 
—

U.S. small cap core
—

 
—

 
—

 
—

 
4.7

 
4.7

 
—

 
—

U.S. small cap value
0.3

 
—

 
0.3

 
—

 
0.3

 
—

 
0.3

 
—

U.S. small cap growth
0.3

 
0.3

 
—

 
—

 
0.2

 
0.2

 
—

 
—

International - blend
1.3

 
1.3

 
—

 
—

 
—

 
—

 
—

 
—

International - developed markets
1.6

 
0.8

 
0.8

 
—

 
1.3

 
0.7

 
0.6

 
—

International - emerging markets
0.4

 
0.4

 
—

 
—

 
0.3

 
0.3

 
—

 
—

Global asset allocation securities
3.6

 
3.2

 
0.4

 
—

 
—

 
—

 
—

 
—

Fixed income securities:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Corporate bonds
0.3

 
—

 
0.3

 
—

 
1.1

 
—

 
1.1

 
—

Government and agency obligations
0.5

 
—

 
0.5

 
—

 
1.0

 
—

 
1.0

 
—

Fixed income funds
3.5

 
1.8

 
1.7

 
—

 
2.6

 
1.0

 
1.6

 
—

Securities lending invested collateral
—

 
—

 
—

 
—

 
0.1

 
0.1

 
—

 
—

 
22.4

 

$12.2

 

$10.2

 

$—

 
25.3

 

$18.7

 

$6.6

 

$—

Due to brokers, net (pending trades with brokers)
—

 
 
 
 
 
 
 
(0.1
)
 
 
 
 
 
 
Due to borrowers for securities lending program
(0.1
)
 
 
 
 
 
 
 
(0.1
)
 
 
 
 
 
 
Total other postretirement benefits plan assets

$22.3

 
 
 
 
 
 
 

$25.1

 
 
 
 
 
 


At December 31, 2012, the current target ranges and actual allocations for Alliant Energy’s, IPL’s and WPL’s VEBA trusts with assets greater than $5 million were as follows:
 
Target Range
 
Actual
 
Allocation
 
Allocation
Cash and equivalents
—
%
-
5%
 
2%
Equity securities:
 
 
 
 
 
Domestic
25
%
-
45%
 
34%
International
10
%
-
20%
 
15%
Global asset allocation securities
20
%
-
40%
 
29%
Fixed income securities
10
%
-
30%
 
20%
Performance-Contingent Restricted Stock [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Schedule Of Equity-based Compensation Plans Activity
A summary of the performance-contingent restricted stock activity was as follows:
 
2012
 
2011
 
2010
 
Shares
 
Weighted
Average
Fair Value
 
Shares
 
Weighted
Average
Fair Value
 
Shares
 
Weighted
Average
Fair Value
Nonvested shares, January 1
301,738

 

$32.60

 
296,190

 

$32.32

 
226,007

 

$32.25

Granted
45,612

 
43.05

 
64,217

 
38.75

 
72,487

 
32.56

Vested (a)
(65,172
)
 
32.56

 
(53,274
)
 
37.93

 
—

 
—

Forfeited (b)
(70,527
)
 
39.93

 
(5,395
)
 
38.00

 
(2,304
)
 
32.56

Nonvested shares, December 31
211,651

 
32.42

 
301,738

 
32.60

 
296,190

 
32.32



(a)
In 2012 and 2011, 65,172 and 53,274 performance-contingent restricted shares granted in 2010 and 2007, respectively, vested because the specified performance criteria for such shares were met.
(b)
In 2012, 65,516 performance-contingent restricted shares granted in 2008 were forfeited because the specified performance criteria for such shares were not met. The remaining forfeitures during 2012, 2011 and 2010 were primarily caused by retirements and terminations of participants.
Non-Qualified Stock Options [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Schedule Of Equity-based Compensation Plans Activity
Options were granted at the market price of the shares on the date of grant, vested over three years and expire no later than 10 years after the grant date. Alliant Energy has not granted any options since 2004. A summary of the stock option activity was as follows:
 
2012
 
2011
 
2010
 
Shares
 
Weighted
Average
Exercise
Price
 
Shares
 
Weighted
Average
Exercise
Price
 
Shares
 
Weighted
Average
Exercise
Price
Outstanding, January 1
63,889

 

$24.21

 
163,680

 

$24.51

 
384,331

 

$27.02

Exercised
(38,711
)
 
24.41

 
(99,791
)
 
24.71

 
(191,433
)
 
28.93

Expired
—

 
—

 
—

 
—

 
(29,218
)
 
28.59

Outstanding and exercisable, December 31
25,178

 
23.89

 
63,889

 
24.21

 
163,680

 
24.51
Time-Based Restricted Stock [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Schedule Of Equity-based Compensation Plans Activity
A summary of the time-based restricted stock activity was as follows:
 
2012
 
2011
 
2010
 
Shares
 
Weighted
Average
Fair Value
 
Shares
 
Weighted
Average
Fair Value
 
Shares
 
Weighted
Average
Fair Value
Nonvested shares, January 1
35,800

 

$30.87

 
70,033

 

$32.27

 
125,349

 

$32.47

Granted
—

 
—

 
5,000

 
39.86

 
—

 
—

Vested
(32,466
)
 
29.95

 
(38,633
)
 
34.60

 
(54,016
)
 
32.72

Forfeited
—

 
—

 
(600
)
 
29.41

 
(1,300
)
 
32.78

Nonvested shares, December 31
3,334

 
39.86

 
35,800

 
30.87

 
70,033

 
32.27
Company Stock Accounts [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Carrying Value And Fair Market Value Of The Deferred Compensation Obligations
At December 31, the carrying value of the deferred compensation obligation for the company stock accounts and the shares in the deferred compensation trust based on the historical value of the shares of Alliant Energy common stock contributed to the rabbi trust, and the fair market value of the shares held in the rabbi trust were as follows (in millions):
 
2012
 
2011
Carrying value

$7.3

 

$8.3

Fair market value
9.5

 
11.6
Performance Shares [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Schedule Of Equity-based Compensation Plans Activity
A summary of the performance shares activity was as follows:
 
2012
 
2011
 
2010
 
Shares (a)
 
Shares (a)
 
Shares (a)
Nonvested shares, January 1
236,979

 
234,518

 
256,579

Granted
45,612

 
64,217

 
72,487

Vested (b)
(111,980
)
 
(57,838
)
 
—

Forfeited (c)
(25,334
)
 
(3,918
)
 
(94,548
)
Nonvested shares, December 31
145,277

 
236,979

 
234,518


(a)
Share amounts represent the target number of performance shares. Each performance share’s value is based on the price of one share of Alliant Energy’s common stock at the end of the performance period. The actual number of shares that will be paid out upon vesting is dependent upon actual performance and may range from zero to 200% of the target number of shares.
(b)
In 2012, 111,980 performance shares granted in 2009 vested at 162.5% of the target, resulting in payouts valued at $8.0 million, which consisted of a combination of cash and common stock (6,399 shares). In 2011, 57,838 performance shares granted in 2008 vested at 75% of the target, resulting in payouts valued at $1.6 million, which consisted of a combination of cash and common stock (1,387 shares).
(c)
In 2010, 57,100 performance shares granted in 2007 were forfeited without payout because the specified performance criteria for such shares were not met. The remaining forfeitures during 2012, 2011 and 2010 were primarily caused by retirements and voluntary terminations of participants.
Performance Units [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Schedule Of Equity-based Compensation Plans Activity
A summary of the performance unit activity was as follows:
 
2012
 
2011
 
2010
 
Units (a)
 
Units (a)
 
Units (a)
Nonvested units, January 1
42,996

 
23,128

 
—

Granted
24,686

 
23,975

 
23,795

Forfeited
(2,713
)
 
(4,107
)
 
(667
)
Nonvested units, December 31
64,969

 
42,996

 
23,128


(a)
Unit amounts represent the target number of performance units. Each performance unit’s value is based on the average price of one share of Alliant Energy’s common stock on the grant date of the award. The actual payout for performance units is dependent upon actual performance and may range from zero to 200% of the target number of units.
Performance Contingent Cash Awards [Member]
  
Defined Benefit Plan Disclosure [Line Items]  
Schedule Of Equity-based Compensation Plans Activity
A summary of the performance contingent cash awards activity was as follows:
 
2012
 
2011
 
2010
 
Awards
 
Awards
 
Awards
Nonvested awards, January 1
46,676

 
23,428

 
—

Granted
36,936

 
23,975

 
23,795

Vested (a)
(21,605
)
 
—

 
—

Forfeited
(2,368
)
 
(727
)
 
(367
)
Nonvested awards, December 31
59,639

 
46,676

 
23,428


(a)
In 2012, 21,605 performance contingent cash awards granted in 2010 vested, resulting in cash payouts valued at $0.9 million.