Benefit Plans

9 Months Ended

Sep. 30, 2018

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan.

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
Alliant Energy	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$3.1			$3.1			$9.1			$9.3			$1.0			$1.2			$3.1			$3.7
Interest cost	11.7			12.7			35.1			38.3			2.0			2.2			5.8			6.5
Expected return on plan assets	(17.4		)	(16.3		)	(52.3		)	(49.1		)	(1.5		)	(1.5		)	(4.5		)	(4.6		)
Amortization of prior service credit	(0.2		)	(0.1		)	(0.5		)	(0.3		)	—			(0.1		)	(0.1		)	(0.2		)
Amortization of actuarial loss	8.8			9.4			26.4			28.2			0.8			1.0			2.5			2.9
Settlement losses (a)	—			0.9			—			0.9			—			—			—			—
		$6.0			$9.7			$17.8			$27.3			$2.3			$2.8			$6.8			$8.3

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$1.8			$1.8			$5.5			$5.5			$0.4			$0.5			$1.3			$1.6
Interest cost	5.3			5.9			16.0			17.6			0.7			0.8			2.3			2.6
Expected return on plan assets	(8.1		)	(7.7		)	(24.4		)	(23.1		)	(1.1		)	(1.0		)	(3.3		)	(3.2		)
Amortization of prior service credit	—			—			(0.1		)	(0.1		)	—			—			—			—
Amortization of actuarial loss	3.7			4.0			11.2			12.1			0.4			0.5			1.0			1.5
		$2.7			$4.0			$8.2			$12.0			$0.4			$0.8			$1.3			$2.5

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
WPL	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$1.1			$1.2			$3.3			$3.6			$0.4			$0.5			$1.2			$1.4
Interest cost	5.0			5.5			15.1			16.4			0.8			0.9			2.3			2.6
Expected return on plan assets	(7.6		)	(7.2		)	(22.8		)	(21.4		)	(0.2		)	(0.2		)	(0.5		)	(0.6		)
Amortization of prior service cost (credit)	—			0.1			(0.1		)	0.1			—			(0.1		)	(0.1		)	(0.2		)
Amortization of actuarial loss	4.3			4.6			12.9			13.9			0.5			0.4			1.5			1.2
		$2.8			$4.2			$8.4			$12.6			$1.5			$1.5			$4.4			$4.4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2018		2017		2018		2017		2018		2017		2018		2017		2018		2017		2018		2017
Compensation expense		$4.2		$5.1		$12.6		$9.9		$2.4		$2.8		$7.0		$5.4		$1.7		$2.1		$5.1		$4.1
Income tax benefits	1.2		2.1		3.6		4.0		0.7		1.1		2.1		2.2		0.5		0.9		1.4		1.7

As of September 30, 2018, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $8.3 million, $4.6 million and $3.5 million, respectively, which is expected to be recognized over a weighted average period of between one and two years.

Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the nine months ended September 30, 2018, with amounts representing the target number of awards, was as follows:

	Performance Shares		Performance Units
Nonvested awards, January 1	223,511		71,737
Granted	74,163		19,840
Vested	(90,806	)	(31,910	)
Forfeited	(905	)	(1,906	)
Nonvested awards, September 30	205,963		57,761

Vested Awards - During the nine months ended September 30, 2018, certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares			Performance Units
Performance awards vested	90,806			31,910
Percentage of target number of performance awards	137.5		%	137.5		%
Aggregate payout value (in millions)		$5.3			$1.4
Payout - cash (in millions)		$4.9			$1.4
Payout - common stock shares issued	5,078			N/A

Fair Value of Awards - At September 28, 2018, Alliant Energy’s common stock closing price was $42.57. Additional information related to fair values of nonvested performance shares and performance units at September 30, 2018, by year of grant, was as follows:

	Performance Shares									Performance Units
	2018 Grant			2017 Grant			2016 Grant			2018 Grant			2017 Grant			2016 Grant
Nonvested awards at target	73,258			65,350			67,355			19,196			18,062			20,503
Estimated payout percentage based on performance criteria	85		%	105		%	143		%	85		%	105		%	143		%
Fair values of each nonvested award		$36.18			$44.70			$60.88			$36.18			$44.70			$60.88

Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the nine months ended September 30, 2018, with amounts representing the target number of units, was as follows:

	Units		Weighted Average Grant Date Fair Value
Nonvested units, January 1	132,705			$36.50
Granted	74,163		38.60
Forfeited	(905	)	38.60
Nonvested units, September 30	205,963		37.25

Restricted Stock Units - A summary of the restricted stock units activity for the nine months ended September 30, 2018, was as follows:

Nonvested units, January 1	113,749
Granted	63,568
Forfeited	(775	)
Nonvested units, September 30	176,542

IPL [Member]

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan.

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
Alliant Energy	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$3.1			$3.1			$9.1			$9.3			$1.0			$1.2			$3.1			$3.7
Interest cost	11.7			12.7			35.1			38.3			2.0			2.2			5.8			6.5
Expected return on plan assets	(17.4		)	(16.3		)	(52.3		)	(49.1		)	(1.5		)	(1.5		)	(4.5		)	(4.6		)
Amortization of prior service credit	(0.2		)	(0.1		)	(0.5		)	(0.3		)	—			(0.1		)	(0.1		)	(0.2		)
Amortization of actuarial loss	8.8			9.4			26.4			28.2			0.8			1.0			2.5			2.9
Settlement losses (a)	—			0.9			—			0.9			—			—			—			—
		$6.0			$9.7			$17.8			$27.3			$2.3			$2.8			$6.8			$8.3

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$1.8			$1.8			$5.5			$5.5			$0.4			$0.5			$1.3			$1.6
Interest cost	5.3			5.9			16.0			17.6			0.7			0.8			2.3			2.6
Expected return on plan assets	(8.1		)	(7.7		)	(24.4		)	(23.1		)	(1.1		)	(1.0		)	(3.3		)	(3.2		)
Amortization of prior service credit	—			—			(0.1		)	(0.1		)	—			—			—			—
Amortization of actuarial loss	3.7			4.0			11.2			12.1			0.4			0.5			1.0			1.5
		$2.7			$4.0			$8.2			$12.0			$0.4			$0.8			$1.3			$2.5

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
WPL	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$1.1			$1.2			$3.3			$3.6			$0.4			$0.5			$1.2			$1.4
Interest cost	5.0			5.5			15.1			16.4			0.8			0.9			2.3			2.6
Expected return on plan assets	(7.6		)	(7.2		)	(22.8		)	(21.4		)	(0.2		)	(0.2		)	(0.5		)	(0.6		)
Amortization of prior service cost (credit)	—			0.1			(0.1		)	0.1			—			(0.1		)	(0.1		)	(0.2		)
Amortization of actuarial loss	4.3			4.6			12.9			13.9			0.5			0.4			1.5			1.2
		$2.8			$4.2			$8.4			$12.6			$1.5			$1.5			$4.4			$4.4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2018		2017		2018		2017		2018		2017		2018		2017		2018		2017		2018		2017
Compensation expense		$4.2		$5.1		$12.6		$9.9		$2.4		$2.8		$7.0		$5.4		$1.7		$2.1		$5.1		$4.1
Income tax benefits	1.2		2.1		3.6		4.0		0.7		1.1		2.1		2.2		0.5		0.9		1.4		1.7

As of September 30, 2018, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $8.3 million, $4.6 million and $3.5 million, respectively, which is expected to be recognized over a weighted average period of between one and two years.

Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the nine months ended September 30, 2018, with amounts representing the target number of awards, was as follows:

	Performance Shares		Performance Units
Nonvested awards, January 1	223,511		71,737
Granted	74,163		19,840
Vested	(90,806	)	(31,910	)
Forfeited	(905	)	(1,906	)
Nonvested awards, September 30	205,963		57,761

Vested Awards - During the nine months ended September 30, 2018, certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares			Performance Units
Performance awards vested	90,806			31,910
Percentage of target number of performance awards	137.5		%	137.5		%
Aggregate payout value (in millions)		$5.3			$1.4
Payout - cash (in millions)		$4.9			$1.4
Payout - common stock shares issued	5,078			N/A

Fair Value of Awards - At September 28, 2018, Alliant Energy’s common stock closing price was $42.57. Additional information related to fair values of nonvested performance shares and performance units at September 30, 2018, by year of grant, was as follows:

	Performance Shares									Performance Units
	2018 Grant			2017 Grant			2016 Grant			2018 Grant			2017 Grant			2016 Grant
Nonvested awards at target	73,258			65,350			67,355			19,196			18,062			20,503
Estimated payout percentage based on performance criteria	85		%	105		%	143		%	85		%	105		%	143		%
Fair values of each nonvested award		$36.18			$44.70			$60.88			$36.18			$44.70			$60.88

Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the nine months ended September 30, 2018, with amounts representing the target number of units, was as follows:

	Units		Weighted Average Grant Date Fair Value
Nonvested units, January 1	132,705			$36.50
Granted	74,163		38.60
Forfeited	(905	)	38.60
Nonvested units, September 30	205,963		37.25

Restricted Stock Units - A summary of the restricted stock units activity for the nine months ended September 30, 2018, was as follows:

Nonvested units, January 1	113,749
Granted	63,568
Forfeited	(775	)
Nonvested units, September 30	176,542

WPL [Member]

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan.

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
Alliant Energy	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$3.1			$3.1			$9.1			$9.3			$1.0			$1.2			$3.1			$3.7
Interest cost	11.7			12.7			35.1			38.3			2.0			2.2			5.8			6.5
Expected return on plan assets	(17.4		)	(16.3		)	(52.3		)	(49.1		)	(1.5		)	(1.5		)	(4.5		)	(4.6		)
Amortization of prior service credit	(0.2		)	(0.1		)	(0.5		)	(0.3		)	—			(0.1		)	(0.1		)	(0.2		)
Amortization of actuarial loss	8.8			9.4			26.4			28.2			0.8			1.0			2.5			2.9
Settlement losses (a)	—			0.9			—			0.9			—			—			—			—
		$6.0			$9.7			$17.8			$27.3			$2.3			$2.8			$6.8			$8.3

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
IPL	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$1.8			$1.8			$5.5			$5.5			$0.4			$0.5			$1.3			$1.6
Interest cost	5.3			5.9			16.0			17.6			0.7			0.8			2.3			2.6
Expected return on plan assets	(8.1		)	(7.7		)	(24.4		)	(23.1		)	(1.1		)	(1.0		)	(3.3		)	(3.2		)
Amortization of prior service credit	—			—			(0.1		)	(0.1		)	—			—			—			—
Amortization of actuarial loss	3.7			4.0			11.2			12.1			0.4			0.5			1.0			1.5
		$2.7			$4.0			$8.2			$12.0			$0.4			$0.8			$1.3			$2.5

	Defined Benefit Pension Plans												OPEB Plans
	Three Months						Nine Months						Three Months						Nine Months
WPL	2018			2017			2018			2017			2018			2017			2018			2017
Service cost		$1.1			$1.2			$3.3			$3.6			$0.4			$0.5			$1.2			$1.4
Interest cost	5.0			5.5			15.1			16.4			0.8			0.9			2.3			2.6
Expected return on plan assets	(7.6		)	(7.2		)	(22.8		)	(21.4		)	(0.2		)	(0.2		)	(0.5		)	(0.6		)
Amortization of prior service cost (credit)	—			0.1			(0.1		)	0.1			—			(0.1		)	(0.1		)	(0.2		)
Amortization of actuarial loss	4.3			4.6			12.9			13.9			0.5			0.4			1.5			1.2
		$2.8			$4.2			$8.4			$12.6			$1.5			$1.5			$4.4			$4.4

(a) Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions):

	Alliant Energy								IPL								WPL
	Three Months				Nine Months				Three Months				Nine Months				Three Months				Nine Months
	2018		2017		2018		2017		2018		2017		2018		2017		2018		2017		2018		2017
Compensation expense		$4.2		$5.1		$12.6		$9.9		$2.4		$2.8		$7.0		$5.4		$1.7		$2.1		$5.1		$4.1
Income tax benefits	1.2		2.1		3.6		4.0		0.7		1.1		2.1		2.2		0.5		0.9		1.4		1.7

As of September 30, 2018, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $8.3 million, $4.6 million and $3.5 million, respectively, which is expected to be recognized over a weighted average period of between one and two years.

Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the nine months ended September 30, 2018, with amounts representing the target number of awards, was as follows:

	Performance Shares		Performance Units
Nonvested awards, January 1	223,511		71,737
Granted	74,163		19,840
Vested	(90,806	)	(31,910	)
Forfeited	(905	)	(1,906	)
Nonvested awards, September 30	205,963		57,761

Vested Awards - During the nine months ended September 30, 2018, certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:

	Performance Shares			Performance Units
Performance awards vested	90,806			31,910
Percentage of target number of performance awards	137.5		%	137.5		%
Aggregate payout value (in millions)		$5.3			$1.4
Payout - cash (in millions)		$4.9			$1.4
Payout - common stock shares issued	5,078			N/A

Fair Value of Awards - At September 28, 2018, Alliant Energy’s common stock closing price was $42.57. Additional information related to fair values of nonvested performance shares and performance units at September 30, 2018, by year of grant, was as follows:

	Performance Shares									Performance Units
	2018 Grant			2017 Grant			2016 Grant			2018 Grant			2017 Grant			2016 Grant
Nonvested awards at target	73,258			65,350			67,355			19,196			18,062			20,503
Estimated payout percentage based on performance criteria	85		%	105		%	143		%	85		%	105		%	143		%
Fair values of each nonvested award		$36.18			$44.70			$60.88			$36.18			$44.70			$60.88

Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the nine months ended September 30, 2018, with amounts representing the target number of units, was as follows:

	Units		Weighted Average Grant Date Fair Value
Nonvested units, January 1	132,705			$36.50
Granted	74,163		38.60
Forfeited	(905	)	38.60
Nonvested units, September 30	205,963		37.25

Restricted Stock Units - A summary of the restricted stock units activity for the nine months ended September 30, 2018, was as follows:

Nonvested units, January 1	113,749
Granted	63,568
Forfeited	(775	)
Nonvested units, September 30	176,542