(5) BENEFIT PLANS

(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs (Credits)—The components of net periodic benefit costs (credits) for Alliant Energy's, IPL's and WPL's sponsored defined benefit pension and other postretirement benefits plans, and defined benefit pension plans amounts directly assigned to IPL and WPL, for the three months ended March 31 are included in the tables below (in millions). In the "IPL" and "WPL" tables below, the qualified defined benefit pension plans costs represent only those respective costs for IPL's and WPL's bargaining unit employees covered under the plans that are sponsored by IPL and WPL, respectively. Also in the "IPL" and "WPL" tables below, the other postretirement benefits plans costs (credits) represent costs (credits) for all IPL and WPL employees, respectively. 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
	2012			2011			2012			2011
Service cost	$	3.3		$	2.9		$	1.7		$	2.1
Interest cost		13.0			13.0			2.6			3.6
Expected return on plan assets		(17.2	)		(16.0	)		(1.9	)		(1.9	)
Amortization of:
Prior service cost (credit)		0.1			0.2			(3.0	)		(0.7	)
Actuarial loss		8.3			5.2			1.6			1.4

	$	7.5		$	5.3		$	1.0		$	4.5


IPL	Qualified Defined Benefit Pension Plans						Other Postretirement Benefits Plans
	2012			2011			2012			2011
Service cost	$	1.9		$	1.6		$	0.8		$	0.8
Interest cost		4.3			4.2			1.1			1.7
Expected return on plan assets		(5.8	)		(5.0	)		(1.3	)		(1.3	)
Amortization of:
Prior service cost (credit)		0.1			0.1			(1.6	)		(0.3	)
Actuarial loss		2.5			1.4			0.9			0.8

	$	3.0		$	2.3		($	0.1	)	$	1.7


WPL	Qualified Defined Benefit Pension Plan						Other Postretirement Benefits Plans
	2012			2011			2012			2011
Service cost	$	1.3		$	1.2		$	0.7		$	0.8
Interest cost		4.1			4.0			1.0			1.4
Expected return on plan assets		(5.6	)		(5.0	)		(0.3	)		(0.3	)
Amortization of:
Prior service cost (credit)		0.1			0.1			(1.0	)		(0.3	)
Actuarial loss		3.1			1.8			0.6			0.5

	$	3.0		$	2.1		$	1.0		$	2.1


Directly assigned defined benefit pension plans	IPL						WPL
	2012			2011			2012			2011
Interest cost	$	1.8		$	1.9		$	1.3		$	1.4
Expected return on plan assets		(2.4	)		(2.4	)		(1.8	)		(1.8	)
Amortization of:
Prior service credit		(0.1	)		(0.1	)		(0.1	)		(0.1	)
Actuarial loss		1.0			0.7			0.9			0.7

	$	0.3		$	0.1		$	0.3		$	0.2

Corporate Services provides services to IPL and WPL, and as a result, IPL and WPL are allocated pension and other postretirement benefits costs associated with Corporate Services employees. 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 for the three months ended March 31 (in millions):


	Pension Benefits Costs				Other Postretirement Benefits Costs
	2012		2011		2012		2011
IPL	$	0.5	$	0.4	$	—	$	0.4
WPL		0.3		0.3		—		0.2

Estimated Future and Actual Employer Contributions—Alliant Energy's, IPL's, and WPL's estimated and actual 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 for 2012 are as follows (in millions):


			Estimated for Calendar Year 2012							Actual Through March 31, 2012
	Alliant Energy			IPL		WPL		Alliant Energy			IPL		WPL
Qualified defined benefit pension plans	$	—		$	—	$	—	$	—		$	—	$	—
Non-qualified defined benefit pension plans (a)		17.0			N/A		N/A		2.1			N/A		N/A
Directly assigned defined benefit pension plans (b)		N/A			0.8		0.2		N/A			0.2		—
Other postretirement benefits plans		5.4			1.1		3.9		2.2			1.1		1.0

(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 Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Cash Balance Plan—Refer to Note 11(b) for discussion of a class action lawsuit filed against the Cash Balance Plan in 2008 and the Internal Revenue Service (IRS) review of the tax qualified status of the Cash Balance Plan.

401(k) Savings Plans—A significant number of Alliant Energy, IPL and WPL employees participate in defined contribution retirement plans (401(k) savings plans). For the three months ended March 31, Alliant Energy's, IPL's and WPL's 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		2012		2011		2012		2011
401(k) costs	$	5.2	$	5.7	$	2.7	$	2.9	$	2.3	$	2.6

(a)	IPL's and WPL's amounts include allocated costs associated with Corporate Services employees.

(b) Equity Incentive Plans—A summary of compensation expense and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):


	Alliant Energy				IPL				WPL
	2012		2011		2012		2011		2012		2011
Compensation expense	$	1.6	$	2.2	$	0.8	$	1.2	$	0.7	$	0.9
Income tax benefits		0.6		0.9		0.3		0.5		0.3		0.4

As of March 31, 2012, total unrecognized compensation cost related to share-based compensation awards was $14.1 million, which is expected to be recognized over a weighted average period of between one and two years. Share-based compensation expense is recognized on a straight-line basis over the requisite service periods and is primarily recorded in "Utility—other operation and maintenance" in the Condensed Consolidated Statements of Income.

In the first quarter of 2012, Alliant Energy granted performance shares, performance units, performance-contingent restricted stock and performance contingent cash awards to certain key employees. Payouts of nonvested awards issued in 2012 are prorated at retirement, death, disability or involuntary termination without cause based on time worked during the first year of the performance period and achievement of the performance criteria. Upon achievement of the performance criteria, payouts of these awards to participants who terminate employment after the first year of the performance period due to retirement, death, disability or involuntary termination without cause are not prorated. Participants' nonvested awards issued in 2012 are forfeited if the participant voluntarily leaves Alliant Energy or is terminated for cause.

Performance Shares and Units—Alliant Energy assumes it will make future payouts of its performance shares and units in cash; therefore, performance shares and units are accounted for as liability awards.

Performance Shares—A summary of the performance shares activity for the three months ended March 31 was as follows:


	2012			2011
	Shares (a)			Shares (a)
Nonvested shares, Jan. 1		236,979			234,518
Granted		45,612			64,217
Vested (b)		(111,980	)		(57,838	)

Nonvested shares, March 31		170,611			240,897

(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 the first quarter of 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 the first quarter of 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).

Performance Units—A summary of the performance unit activity for the three months ended March 31 was as follows:


	2012			2011
	Units (a)			Units (a)
Nonvested units, Jan. 1		42,996			23,128
Granted		24,686			23,975
Forfeited		(878	)		(569	)

Nonvested units, March 31		66,804			46,534

(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.

Fair Value of Awards—Information related to fair values of nonvested performance shares and units at March 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			62,170			62,829			24,686			21,693			20,425
Alliant Energy common stock closing price on March 31, 2012	$	43.32		$	43.32		$	43.32
Alliant Energy common stock average price on grant date										$	43.05		$	38.75		$	32.56
Estimated payout percentage based on performance criteria		93	%		105	%		161	%		93	%		105	%		161	%
Fair values of each nonvested award	$	40.29		$	45.49		$	69.75		$	40.04		$	40.69		$	52.41

At March 31, 2012, fair values of nonvested performance shares and units were calculated using a Monte Carlo simulation to determine the anticipated total shareowner returns of Alliant Energy and its investor-owned utility peer groups. Expected volatility was based on historical volatilities using daily stock prices over the past three years. Expected dividend yields were calculated based on the most recent quarterly dividend rates announced prior to the measurement date and stock prices at the measurement date. The risk-free interest rate was based on the three-year U.S. Treasury rate in effect as of the measurement date.

Restricted Stock—Restricted stock consists of time-based and performance-contingent restricted stock.

Time-based restricted stock—A summary of the time-based restricted stock activity for the three months ended March 31 was as follows:


	2012					2011
	Shares			Weighted Average Fair Value		Shares			Weighted Average Fair Value
Nonvested shares, Jan. 1		35,800		$	30.87		70,033		$	32.27
Granted		—			—		5,000			39.86
Vested		(32,466	)		29.95		(33,516	)		35.34

Nonvested shares, March 31		3,334			39.86		41,517			30.71

Performance-contingent restricted stock—A summary of the performance-contingent restricted stock activity for the three months ended March 31 was as follows:


	2012					2011
	Shares			Weighted Average Fair Value		Shares			Weighted Average Fair Value
Nonvested shares, Jan. 1		301,738		$	32.60		296,190		$	32.32
Granted		45,612			43.05		64,217			38.75
Vested		(65,172	)		32.56		(53,274	)		37.93
Forfeited		(70,527	)		39.93		(5,395	)		38.00

Nonvested shares, March 31		211,651			32.42		301,738			32.60

Non-qualified Stock Options—A summary of the stock option activity for the three months ended March 31 was as follows:


	2012					2011
	Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price
Outstanding, Jan. 1		63,889		$	24.21		163,680		$	24.51
Exercised		(13,400	)		24.83		(20,591	)		27.79

Outstanding and exercisable, March 31		50,489			24.04		143,089			24.04

The weighted average remaining contractual term for options outstanding and exercisable at March 31, 2012 was between one and two years. The aggregate intrinsic value of options outstanding and exercisable at March 31, 2012 was $1.0 million.

Other information related to stock option activity for the three months ended March 31 was as follows (in millions):


	2012		2011
Cash received from stock options exercised	$	0.3	$	0.6
Aggregate intrinsic value of stock options exercised		0.2		0.2
Income tax benefit from the exercise of stock options		0.1		0.1

Performance Contingent Cash Awards—A summary of the performance contingent cash awards activity for the three months ended March 31 was as follows:


	2012			2011
	Awards			Awards
Nonvested awards, Jan. 1		46,676			23,428
Granted		36,936			23,975
Vested (a)		(21,605	)		—
Forfeited		(1,533	)		—

Nonvested awards, March 31		60,474			47,403

(a)

In the first quarter of 2012, 21,605 performance contingent cash awards granted in 2010 vested, resulting in cash payouts valued at $0.9 million.

Benefit Plans

(5) BENEFIT PLANS

(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs (Credits)—The components of net periodic benefit costs (credits) for Alliant Energy's, IPL's and WPL's sponsored defined benefit pension and other postretirement benefits plans, and defined benefit pension plans amounts directly assigned to IPL and WPL, for the three months ended March 31 are included in the tables below (in millions). In the "IPL" and "WPL" tables below, the qualified defined benefit pension plans costs represent only those respective costs for IPL's and WPL's bargaining unit employees covered under the plans that are sponsored by IPL and WPL, respectively. Also in the "IPL" and "WPL" tables below, the other postretirement benefits plans costs (credits) represent costs (credits) for all IPL and WPL employees, respectively. 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
Alliant Energy	2012			2011			2012			2011
Service cost	$	3.3		$	2.9		$	1.7		$	2.1
Interest cost		13.0			13.0			2.6			3.6
Expected return on plan assets		(17.2	)		(16.0	)		(1.9	)		(1.9	)
Amortization of:
Prior service cost (credit)		0.1			0.2			(3.0	)		(0.7	)
Actuarial loss		8.3			5.2			1.6			1.4

	$	7.5		$	5.3		$	1.0		$	4.5


IPL	Qualified Defined Benefit Pension Plans						Other Postretirement Benefits Plans
IPL	2012			2011			2012			2011
Service cost	$	1.9		$	1.6		$	0.8		$	0.8
Interest cost		4.3			4.2			1.1			1.7
Expected return on plan assets		(5.8	)		(5.0	)		(1.3	)		(1.3	)
Amortization of:
Prior service cost (credit)		0.1			0.1			(1.6	)		(0.3	)
Actuarial loss		2.5			1.4			0.9			0.8

	$	3.0		$	2.3		($	0.1	)	$	1.7


WPL	Qualified Defined Benefit Pension Plan						Other Postretirement Benefits Plans
WPL	2012			2011			2012			2011
Service cost	$	1.3		$	1.2		$	0.7		$	0.8
Interest cost		4.1			4.0			1.0			1.4
Expected return on plan assets		(5.6	)		(5.0	)		(0.3	)		(0.3	)
Amortization of:
Prior service cost (credit)		0.1			0.1			(1.0	)		(0.3	)
Actuarial loss		3.1			1.8			0.6			0.5

	$	3.0		$	2.1		$	1.0		$	2.1


Directly assigned defined benefit pension plans	IPL						WPL
Directly assigned defined benefit pension plans	2012			2011			2012			2011
Interest cost	$	1.8		$	1.9		$	1.3		$	1.4
Expected return on plan assets		(2.4	)		(2.4	)		(1.8	)		(1.8	)
Amortization of:
Prior service credit		(0.1	)		(0.1	)		(0.1	)		(0.1	)
Actuarial loss		1.0			0.7			0.9			0.7

	$	0.3		$	0.1		$	0.3		$	0.2

Corporate Services provides services to IPL and WPL, and as a result, IPL and WPL are allocated pension and other postretirement benefits costs associated with Corporate Services employees. 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 for the three months ended March 31 (in millions):


	Pension Benefits				Other Postretirement
	Costs				Benefits Costs
	2012		2011		2012		2011
IPL	$	0.5	$	0.4	$	—	$	0.4
WPL		0.3		0.3		—		0.2

Estimated Future and Actual Employer Contributions—Alliant Energy's, IPL's, and WPL's estimated and actual 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 for 2012 are as follows (in millions):


	Estimated for Calendar Year 2012						Actual Through March 31, 2012
	Alliant Energy		IPL		WPL		Alliant Energy		IPL		WPL
Qualified defined benefit pension plans	$	—	$	—	$	—	$	—	$	—	$	—
Non-qualified defined benefit pension plans (a)		17.0		N/A		N/A		2.1		N/A		N/A
Directly assigned defined benefit pension plans (b)		N/A		0.8		0.2		N/A		0.2		—
Other postretirement benefits plans		5.4		1.1		3.9		2.2		1.1		1.0

(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 Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Cash Balance Plan—Refer to Note 11(b) for discussion of a class action lawsuit filed against the Cash Balance Plan in 2008 and the Internal Revenue Service (IRS) review of the tax qualified status of the Cash Balance Plan.

401(k) Savings Plans—A significant number of Alliant Energy, IPL and WPL employees participate in defined contribution retirement plans (401(k) savings plans). For the three months ended March 31, Alliant Energy's, IPL's and WPL's 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		2012		2011		2012		2011
401(k) costs	$	5.2	$	5.7	$	2.7	$	2.9	$	2.3	$	2.6

(a)	IPL's and WPL's amounts include allocated costs associated with Corporate Services employees.

(b) Equity Incentive Plans—A summary of compensation expense and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):


	Alliant Energy				IPL				WPL
	2012		2011		2012		2011		2012		2011
Compensation expense	$	1.6	$	2.2	$	0.8	$	1.2	$	0.7	$	0.9
Income tax benefits		0.6		0.9		0.3		0.5		0.3		0.4

As of March 31, 2012, total unrecognized compensation cost related to share-based compensation awards was $14.1 million, which is expected to be recognized over a weighted average period of between one and two years. Share-based compensation expense is recognized on a straight-line basis over the requisite service periods and is primarily recorded in "Utility—other operation and maintenance" in the Condensed Consolidated Statements of Income.

In the first quarter of 2012, Alliant Energy granted performance shares, performance units, performance-contingent restricted stock and performance contingent cash awards to certain key employees. Payouts of nonvested awards issued in 2012 are prorated at retirement, death, disability or involuntary termination without cause based on time worked during the first year of the performance period and achievement of the performance criteria. Upon achievement of the performance criteria, payouts of these awards to participants who terminate employment after the first year of the performance period due to retirement, death, disability or involuntary termination without cause are not prorated. Participants' nonvested awards issued in 2012 are forfeited if the participant voluntarily leaves Alliant Energy or is terminated for cause.

Performance Shares and Units—Alliant Energy assumes it will make future payouts of its performance shares and units in cash; therefore, performance shares and units are accounted for as liability awards.

Performance Shares—A summary of the performance shares activity for the three months ended March 31 was as follows:


	2012			2011
	Shares (a)			Shares (a)
Nonvested shares, Jan. 1		236,979			234,518
Granted		45,612			64,217
Vested (b)		(111,980	)		(57,838	)

Nonvested shares, March 31		170,611			240,897

(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 the first quarter of 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 the first quarter of 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).

Performance Units—A summary of the performance unit activity for the three months ended March 31 was as follows:


	2012			2011
	Units (a)			Units (a)
Nonvested units, Jan. 1		42,996			23,128
Granted		24,686			23,975
Forfeited		(878	)		(569	)

Nonvested units, March 31		66,804			46,534

(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.

Fair Value of Awards—Information related to fair values of nonvested performance shares and units at March 31, 2012, by year of grant, were as follows:


	Performance Shares									Performance Units
	2012			2011			2010			2012			2011			2010
	Grant			Grant			Grant			Grant			Grant			Grant
Nonvested awards		45,612			62,170			62,829			24,686			21,693			20,425
Alliant Energy common stock closing price on March 31, 2012	$	43.32		$	43.32		$	43.32
Alliant Energy common stock average price on grant date										$	43.05		$	38.75		$	32.56
Estimated payout percentage based on performance criteria		93	%		105	%		161	%		93	%		105	%		161	%
Fair values of each nonvested award	$	40.29		$	45.49		$	69.75		$	40.04		$	40.69		$	52.41

At March 31, 2012, fair values of nonvested performance shares and units were calculated using a Monte Carlo simulation to determine the anticipated total shareowner returns of Alliant Energy and its investor-owned utility peer groups. Expected volatility was based on historical volatilities using daily stock prices over the past three years. Expected dividend yields were calculated based on the most recent quarterly dividend rates announced prior to the measurement date and stock prices at the measurement date. The risk-free interest rate was based on the three-year U.S. Treasury rate in effect as of the measurement date.

Restricted Stock—Restricted stock consists of time-based and performance-contingent restricted stock.

Time-based restricted stock—A summary of the time-based restricted stock activity for the three months ended March 31 was as follows:


	2012					2011
				Weighted					Weighted
				Average					Average
	Shares			Fair Value		Shares			Fair Value
Nonvested shares, Jan. 1		35,800		$	30.87		70,033		$	32.27
Granted		—			—		5,000			39.86
Vested		(32,466	)		29.95		(33,516	)		35.34

Nonvested shares, March 31		3,334			39.86		41,517			30.71

Performance-contingent restricted stock—A summary of the performance-contingent restricted stock activity for the three months ended March 31 was as follows:


	2012					2011
				Weighted					Weighted
				Average					Average
	Shares			Fair Value		Shares			Fair Value
Nonvested shares, Jan. 1		301,738		$	32.60		296,190		$	32.32
Granted		45,612			43.05		64,217			38.75
Vested		(65,172	)		32.56		(53,274	)		37.93
Forfeited		(70,527	)		39.93		(5,395	)		38.00

Nonvested shares, March 31		211,651			32.42		301,738			32.60

Non-qualified Stock Options—A summary of the stock option activity for the three months ended March 31 was as follows:

2012

2011

Weighted

Weighted

Average

Average

Exercise

Exercise

Shares

Price

Shares

Price

Outstanding, Jan. 1

63,889

$

24.21

163,680

$

24.51

Exercised

(13,400

)

24.83

(20,591

)

27.79

Outstanding and exercisable, March 31

50,489

24.04

143,089

24.04

The weighted average remaining contractual term for options outstanding and exercisable at March 31, 2012 was between one and two years. The aggregate intrinsic value of options outstanding and exercisable at March 31, 2012 was $1.0 million.

Other information related to stock option activity for the three months ended March 31 was as follows (in millions):


	2012		2011
Cash received from stock options exercised	$	0.3	$	0.6
Aggregate intrinsic value of stock options exercised		0.2		0.2
Income tax benefit from the exercise of stock options		0.1		0.1

Performance Contingent Cash Awards—A summary of the performance contingent cash awards activity for the three months ended March 31 was as follows:


	2012			2011
	Awards			Awards
Nonvested awards, Jan. 1		46,676			23,428
Granted		36,936			23,975
Vested (a)		(21,605	)		—
Forfeited		(1,533	)		—

Nonvested awards, March 31		60,474			47,403

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

Benefit Plans

(5) BENEFIT PLANS

(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs (Credits)—The components of net periodic benefit costs (credits) for Alliant Energy's, IPL's and WPL's sponsored defined benefit pension and other postretirement benefits plans, and defined benefit pension plans amounts directly assigned to IPL and WPL, for the three months ended March 31 are included in the tables below (in millions). In the "IPL" and "WPL" tables below, the qualified defined benefit pension plans costs represent only those respective costs for IPL's and WPL's bargaining unit employees covered under the plans that are sponsored by IPL and WPL, respectively. Also in the "IPL" and "WPL" tables below, the other postretirement benefits plans costs (credits) represent costs (credits) for all IPL and WPL employees, respectively. 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
Alliant Energy	2012			2011			2012			2011
Service cost	$	3.3		$	2.9		$	1.7		$	2.1
Interest cost		13.0			13.0			2.6			3.6
Expected return on plan assets		(17.2	)		(16.0	)		(1.9	)		(1.9	)
Amortization of:
Prior service cost (credit)		0.1			0.2			(3.0	)		(0.7	)
Actuarial loss		8.3			5.2			1.6			1.4

	$	7.5		$	5.3		$	1.0		$	4.5


IPL	Qualified Defined Benefit Pension Plans						Other Postretirement Benefits Plans
IPL	2012			2011			2012			2011
Service cost	$	1.9		$	1.6		$	0.8		$	0.8
Interest cost		4.3			4.2			1.1			1.7
Expected return on plan assets		(5.8	)		(5.0	)		(1.3	)		(1.3	)
Amortization of:
Prior service cost (credit)		0.1			0.1			(1.6	)		(0.3	)
Actuarial loss		2.5			1.4			0.9			0.8

	$	3.0		$	2.3		($	0.1	)	$	1.7


WPL	Qualified Defined Benefit Pension Plan						Other Postretirement Benefits Plans
WPL	2012			2011			2012			2011
Service cost	$	1.3		$	1.2		$	0.7		$	0.8
Interest cost		4.1			4.0			1.0			1.4
Expected return on plan assets		(5.6	)		(5.0	)		(0.3	)		(0.3	)
Amortization of:
Prior service cost (credit)		0.1			0.1			(1.0	)		(0.3	)
Actuarial loss		3.1			1.8			0.6			0.5

	$	3.0		$	2.1		$	1.0		$	2.1


Directly assigned defined benefit pension plans	IPL						WPL
Directly assigned defined benefit pension plans	2012			2011			2012			2011
Interest cost	$	1.8		$	1.9		$	1.3		$	1.4
Expected return on plan assets		(2.4	)		(2.4	)		(1.8	)		(1.8	)
Amortization of:
Prior service credit		(0.1	)		(0.1	)		(0.1	)		(0.1	)
Actuarial loss		1.0			0.7			0.9			0.7

	$	0.3		$	0.1		$	0.3		$	0.2

Corporate Services provides services to IPL and WPL, and as a result, IPL and WPL are allocated pension and other postretirement benefits costs associated with Corporate Services employees. 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 for the three months ended March 31 (in millions):


	Pension Benefits				Other Postretirement
	Costs				Benefits Costs
	2012		2011		2012		2011
IPL	$	0.5	$	0.4	$	—	$	0.4
WPL		0.3		0.3		—		0.2

Estimated Future and Actual Employer Contributions—Alliant Energy's, IPL's, and WPL's estimated and actual 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 for 2012 are as follows (in millions):


	Estimated for Calendar Year 2012						Actual Through March 31, 2012
	Alliant Energy		IPL		WPL		Alliant Energy		IPL		WPL
Qualified defined benefit pension plans	$	—	$	—	$	—	$	—	$	—	$	—
Non-qualified defined benefit pension plans (a)		17.0		N/A		N/A		2.1		N/A		N/A
Directly assigned defined benefit pension plans (b)		N/A		0.8		0.2		N/A		0.2		—
Other postretirement benefits plans		5.4		1.1		3.9		2.2		1.1		1.0

(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 Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans.

Cash Balance Plan—Refer to Note 11(b) for discussion of a class action lawsuit filed against the Cash Balance Plan in 2008 and the Internal Revenue Service (IRS) review of the tax qualified status of the Cash Balance Plan.

401(k) Savings Plans—A significant number of Alliant Energy, IPL and WPL employees participate in defined contribution retirement plans (401(k) savings plans). For the three months ended March 31, Alliant Energy's, IPL's and WPL's 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		2012		2011		2012		2011
401(k) costs	$	5.2	$	5.7	$	2.7	$	2.9	$	2.3	$	2.6

(a)	IPL's and WPL's amounts include allocated costs associated with Corporate Services employees.

(b) Equity Incentive Plans—A summary of compensation expense and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):


	Alliant Energy				IPL				WPL
	2012		2011		2012		2011		2012		2011
Compensation expense	$	1.6	$	2.2	$	0.8	$	1.2	$	0.7	$	0.9
Income tax benefits		0.6		0.9		0.3		0.5		0.3		0.4

As of March 31, 2012, total unrecognized compensation cost related to share-based compensation awards was $14.1 million, which is expected to be recognized over a weighted average period of between one and two years. Share-based compensation expense is recognized on a straight-line basis over the requisite service periods and is primarily recorded in "Utility—other operation and maintenance" in the Condensed Consolidated Statements of Income.

In the first quarter of 2012, Alliant Energy granted performance shares, performance units, performance-contingent restricted stock and performance contingent cash awards to certain key employees. Payouts of nonvested awards issued in 2012 are prorated at retirement, death, disability or involuntary termination without cause based on time worked during the first year of the performance period and achievement of the performance criteria. Upon achievement of the performance criteria, payouts of these awards to participants who terminate employment after the first year of the performance period due to retirement, death, disability or involuntary termination without cause are not prorated. Participants' nonvested awards issued in 2012 are forfeited if the participant voluntarily leaves Alliant Energy or is terminated for cause.

Performance Shares and Units—Alliant Energy assumes it will make future payouts of its performance shares and units in cash; therefore, performance shares and units are accounted for as liability awards.

Performance Shares—A summary of the performance shares activity for the three months ended March 31 was as follows:


	2012			2011
	Shares (a)			Shares (a)
Nonvested shares, Jan. 1		236,979			234,518
Granted		45,612			64,217
Vested (b)		(111,980	)		(57,838	)

Nonvested shares, March 31		170,611			240,897

(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 the first quarter of 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 the first quarter of 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).

Performance Units—A summary of the performance unit activity for the three months ended March 31 was as follows:


	2012			2011
	Units (a)			Units (a)
Nonvested units, Jan. 1		42,996			23,128
Granted		24,686			23,975
Forfeited		(878	)		(569	)

Nonvested units, March 31		66,804			46,534

(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.

Fair Value of Awards—Information related to fair values of nonvested performance shares and units at March 31, 2012, by year of grant, were as follows:


	Performance Shares									Performance Units
	2012			2011			2010			2012			2011			2010
	Grant			Grant			Grant			Grant			Grant			Grant
Nonvested awards		45,612			62,170			62,829			24,686			21,693			20,425
Alliant Energy common stock closing price on March 31, 2012	$	43.32		$	43.32		$	43.32
Alliant Energy common stock average price on grant date										$	43.05		$	38.75		$	32.56
Estimated payout percentage based on performance criteria		93	%		105	%		161	%		93	%		105	%		161	%
Fair values of each nonvested award	$	40.29		$	45.49		$	69.75		$	40.04		$	40.69		$	52.41

At March 31, 2012, fair values of nonvested performance shares and units were calculated using a Monte Carlo simulation to determine the anticipated total shareowner returns of Alliant Energy and its investor-owned utility peer groups. Expected volatility was based on historical volatilities using daily stock prices over the past three years. Expected dividend yields were calculated based on the most recent quarterly dividend rates announced prior to the measurement date and stock prices at the measurement date. The risk-free interest rate was based on the three-year U.S. Treasury rate in effect as of the measurement date.

Restricted Stock—Restricted stock consists of time-based and performance-contingent restricted stock.

Time-based restricted stock—A summary of the time-based restricted stock activity for the three months ended March 31 was as follows:


	2012					2011
				Weighted					Weighted
				Average					Average
	Shares			Fair Value		Shares			Fair Value
Nonvested shares, Jan. 1		35,800		$	30.87		70,033		$	32.27
Granted		—			—		5,000			39.86
Vested		(32,466	)		29.95		(33,516	)		35.34

Nonvested shares, March 31		3,334			39.86		41,517			30.71

Performance-contingent restricted stock—A summary of the performance-contingent restricted stock activity for the three months ended March 31 was as follows:


	2012					2011
				Weighted					Weighted
				Average					Average
	Shares			Fair Value		Shares			Fair Value
Nonvested shares, Jan. 1		301,738		$	32.60		296,190		$	32.32
Granted		45,612			43.05		64,217			38.75
Vested		(65,172	)		32.56		(53,274	)		37.93
Forfeited		(70,527	)		39.93		(5,395	)		38.00

Nonvested shares, March 31		211,651			32.42		301,738			32.60

Non-qualified Stock Options—A summary of the stock option activity for the three months ended March 31 was as follows:

2012

2011

Weighted

Weighted

Average

Average

Exercise

Exercise

Shares

Price

Shares

Price

Outstanding, Jan. 1

63,889

$

24.21

163,680

$

24.51

Exercised

(13,400

)

24.83

(20,591

)

27.79

Outstanding and exercisable, March 31

50,489

24.04

143,089

24.04

The weighted average remaining contractual term for options outstanding and exercisable at March 31, 2012 was between one and two years. The aggregate intrinsic value of options outstanding and exercisable at March 31, 2012 was $1.0 million.

Other information related to stock option activity for the three months ended March 31 was as follows (in millions):


	2012		2011
Cash received from stock options exercised	$	0.3	$	0.6
Aggregate intrinsic value of stock options exercised		0.2		0.2
Income tax benefit from the exercise of stock options		0.1		0.1

Performance Contingent Cash Awards—A summary of the performance contingent cash awards activity for the three months ended March 31 was as follows:


	2012			2011
	Awards			Awards
Nonvested awards, Jan. 1		46,676			23,428
Granted		36,936			23,975
Vested (a)		(21,605	)		—
Forfeited		(1,533	)		—

Nonvested awards, March 31		60,474			47,403

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