Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Defined Benefit Plan Disclosure [Line Items]

Assumptions Used To Measure Benefit Plans

The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans												OPEB Plans
Alliant Energy	2017				2016				2015				2017	2016	2015
Discount rate for benefit obligations	3.66%				4.19%				4.47%				3.53%	3.98%	4.30%
Discount rate for net periodic cost	4.19%				4.47%				4.18%				3.98%	4.30%	3.97%
Expected rate of return on plan assets	7.60%				7.60%				7.60%				5.80%	6.30%	6.20%
Rate of compensation increase	3.65	%	-	4.50%	3.65	%	-	4.50%	3.65	%	-	4.50%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A				N/A				N/A				6.75%	7.00%	7.25%
Ultimate trend rate	N/A				N/A				N/A				5.00%	5.00%	5.00%

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2017	2016	2015	2017	2016	2015
Discount rate for benefit obligations	3.68%	4.22%	4.50%	3.51%	3.95%	4.28%
Discount rate for net periodic cost	4.22%	4.50%	4.20%	3.95%	4.28%	3.94%
Expected rate of return on plan assets	7.60%	7.60%	7.60%	6.20%	6.60%	6.60%
Rate of compensation increase	3.65%	3.65%	3.65%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A	N/A	N/A	6.75%	7.00%	7.25%
Ultimate trend rate	N/A	N/A	N/A	5.00%	5.00%	5.00%

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2017	2016	2015	2017	2016	2015
Discount rate for benefit obligations	3.69%	4.23%	4.51%	3.51%	3.96%	4.28%
Discount rate for net periodic cost	4.23%	4.51%	4.20%	3.96%	4.28%	3.96%
Expected rate of return on plan assets	7.60%	7.60%	7.60%	3.50%	4.70%	4.60%
Rate of compensation increase	3.65%	3.65%	3.65%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A	N/A	N/A	6.75%	7.00%	7.25%
Ultimate trend rate	N/A	N/A	N/A	5.00%	5.00%	5.00%

Net Periodic Benefit Costs (Credits)

The components of net periodic benefit costs (credits) for sponsored defined benefit pension and OPEB plans are included in the tables below (in millions). Net periodic benefit costs are primarily included in “Other operation and maintenance” in the income statements.

Alliant Energy	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$12.5			$12.6			$15.9			$5.0			$5.3			$5.5
Interest cost	51.0			53.0			53.6			8.6			9.4			9.1
Expected return on plan assets (a)	(65.5		)	(65.5		)	(75.0		)	(6.1		)	(6.1		)	(8.4		)
Amortization of prior service credit (b)	(0.4		)	(0.3		)	(0.2		)	(0.2		)	(4.1		)	(11.3		)
Amortization of actuarial loss (c)	37.6			37.4			35.4			3.8			4.7			4.8
Additional benefit costs	—			—			0.5			—			—			—
Settlement losses (d)	0.9			—			—			—			—			—
		$36.1			$37.2			$30.2			$11.1			$9.2			($0.3	)

IPL	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$7.3			$7.5			$8.8			$2.1			$2.3			$2.4
Interest cost	23.5			24.5			25.0			3.5			3.8			3.8
Expected return on plan assets (a)	(30.8		)	(30.9		)	(35.8		)	(4.3		)	(4.3		)	(5.7		)
Amortization of prior service credit (b)	(0.2		)	(0.2		)	(0.1		)	—			(2.6		)	(6.1		)
Amortization of actuarial loss (c)	16.1			16.5			15.3			2.0			2.6			2.3
		$15.9			$17.4			$13.2			$3.3			$1.8			($3.3	)

WPL	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$4.9			$4.9			$5.8			$1.9			$2.0			$2.1
Interest cost	21.8			22.3			22.6			3.4			3.8			3.7
Expected return on plan assets (a)	(28.5		)	(28.3		)	(32.4		)	(0.8		)	(0.8		)	(1.5		)
Amortization of prior service cost (credit) (b)	0.1			0.2			0.2			(0.2		)	(0.9		)	(3.5		)
Amortization of actuarial loss (c)	18.5			17.6			16.8			1.6			1.8			2.2
Additional benefit costs	—			—			0.5			—			—			—
		$16.8			$16.7			$13.5			$5.9			$5.9			$3.0

(a) 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.

(b) Unrecognized prior service costs (credits) for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(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 where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

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

Estimated Amortization From Regulatory Assets, Regulatory Liabilities And Accumulated Other Comprehensive Loss Into Net Periodic Benefit Cost

The estimated amortization from “Regulatory assets” and “Regulatory liabilities” on the balance sheets and AOCL on Alliant Energy’s balance sheet into net periodic benefit cost in 2018 is as follows (in millions):

	Alliant Energy						IPL					WPL
	Defined Benefit						Defined Benefit					Defined Benefit
	Pension Plans			OPEB Plans			Pension Plans			OPEB Plans		Pension Plans			OPEB Plans
Actuarial loss		$35.2			$3.4			$15.0			$1.2		$17.2			$2.0
Prior service credit	(0.7		)	(0.2		)	(0.2		)	—		(0.2		)	(0.2		)
		$34.5			$3.2			$14.8			$1.2		$17.0			$1.8

Funded Status Of Benefit Plans

A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$1,244.3			$1,206.3			$220.1			$221.4
Service cost	12.5			12.6			5.0			5.3
Interest cost	51.0			53.0			8.6			9.4
Plan participants’ contributions	—			—			2.9			2.4
Actuarial (gain) loss	83.6			48.3			5.4			(0.3		)
Gross benefits paid	(88.3		)	(75.9		)	(19.7		)	(18.1		)
Net benefit obligation at December 31	1,303.1			1,244.3			222.3			220.1
Change in plan assets:
Fair value of plan assets at January 1	895.7			895.0			105.8			106.9
Actual return on plan assets	136.7			74.3			12.9			8.2
Employer contributions	6.6			2.3			9.2			6.4
Plan participants’ contributions	—			—			2.9			2.4
Gross benefits paid	(88.3		)	(75.9		)	(19.7		)	(18.1		)
Fair value of plan assets at December 31	950.7			895.7			111.1			105.8
Under funded status at December 31		($352.4	)		($348.6	)		($111.2	)		($114.3	)

	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$8.8			$3.2
Current liabilities	(2.2		)	(6.5		)	(9.1		)	(8.6		)
Pension and other benefit obligations	(350.2		)	(342.1		)	(110.9		)	(108.9		)
Net amounts recognized at December 31		($352.4	)		($348.6	)		($111.2	)		($114.3	)
Amounts recognized in Regulatory Assets (refer to Note 2 for details) and AOCL (refer to Alliant Energy’s common equity statements for details) consist of:
Net actuarial loss		$509.1			$535.1			$47.4			$52.6
Prior service credit	(6.5		)	(6.9		)	(1.3		)	(1.5		)
		$502.6			$528.2			$46.1			$51.1

	Defined Benefit Pension Plans						OPEB Plans
IPL	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$570.4			$556.1			$90.1			$91.3
Service cost	7.3			7.5			2.1			2.3
Interest cost	23.5			24.5			3.5			3.8
Plan participants’ contributions	—			—			1.0			0.9
Actuarial (gain) loss	34.9			19.1			(0.1		)	(0.7		)
Gross benefits paid	(43.2		)	(36.8		)	(7.2		)	(7.5		)
Net benefit obligation at December 31	592.9			570.4			89.4			90.1
Change in plan assets:
Fair value of plan assets at January 1	422.0			422.7			68.2			69.2
Actual return on plan assets	64.3			35.3			8.9			5.3
Employer contributions	0.6			0.8			2.0			0.3
Plan participants’ contributions	—			—			1.0			0.9
Gross benefits paid	(43.2		)	(36.8		)	(7.2		)	(7.5		)
Fair value of plan assets at December 31	443.7			422.0			72.9			68.2
Under funded status at December 31		($149.2	)		($148.4	)		($16.5	)		($21.9	)

	Defined Benefit Pension Plans						OPEB Plans
IPL	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$5.9			$0.4
Current liabilities	(0.5		)	(0.7		)	(2.0		)	(1.9		)
Pension and other benefit obligations	(148.7		)	(147.7		)	(20.4		)	(20.4		)
Net amounts recognized at December 31		($149.2	)		($148.4	)		($16.5	)		($21.9	)
Amounts recognized in Regulatory Assets consist of (refer to Note 2 for details):
Net actuarial loss		$218.9			$233.6			$18.7			$25.4
Prior service credit	(2.1		)	(2.3		)	—			—
		$216.8			$231.3			$18.7			$25.4

	Defined Benefit Pension Plans						OPEB Plans
WPL	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$529.2			$505.9			$88.9			$89.7
Service cost	4.9			4.9			1.9			2.0
Interest cost	21.8			22.3			3.4			3.8
Plan participants’ contributions	—			—			1.4			1.2
Actuarial loss	38.3			25.7			4.1			0.5
Gross benefits paid	(34.4		)	(29.6		)	(9.3		)	(8.3		)
Net benefit obligation at December 31	559.8			529.2			90.4			88.9
Change in plan assets:
Fair value of plan assets at January 1	389.7			386.8			18.6			18.7
Actual return on plan assets	59.6			32.4			1.2			1.2
Employer contributions	0.1			0.1			6.8			5.8
Plan participants’ contributions	—			—			1.4			1.2
Gross benefits paid	(34.4		)	(29.6		)	(9.3		)	(8.3		)
Fair value of plan assets at December 31	415.0			389.7			18.7			18.6
Under funded status at December 31		($144.8	)		($139.5	)		($71.7	)		($70.3	)

	Defined Benefit Pension Plans						OPEB Plans
WPL	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$2.9			$2.7
Current liabilities	(0.1		)	(0.1		)	(6.8		)	(6.4		)
Pension and other benefit obligations	(144.7		)	(139.4		)	(67.8		)	(66.6		)
Net amounts recognized at December 31		($144.8	)		($139.5	)		($71.7	)		($70.3	)
Amounts recognized in Regulatory Assets consist of (refer to Note 2 for details):
Net actuarial loss		$224.7			$236.1			$23.6			$21.5
Prior service credit	(1.5		)	(1.4		)	(1.3		)	(1.5		)
		$223.2			$234.7			$22.3			$20.0

Accumulated Benefit Obligations

Included in the following tables are accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB 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 (in millions):

	Defined Benefit Pension Plans				OPEB Plans
Alliant Energy	2017		2016		2017		2016
Accumulated benefit obligations		$1,269.0		$1,201.5		$222.3		$220.1
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,269.0		1,201.5		222.3		220.1
Fair value of plan assets	950.7		895.7		111.1		105.8
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,303.1		1,244.3		N/A		N/A
Fair value of plan assets	950.7		895.7		N/A		N/A

	Defined Benefit Pension Plans				OPEB Plans
IPL	2017		2016		2017		2016
Accumulated benefit obligations		$573.1		$546.7		$89.4		$90.1
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	573.1		546.7		89.4		90.1
Fair value of plan assets	443.7		422.0		72.9		68.2
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	592.9		570.4		N/A		N/A
Fair value of plan assets	443.7		422.0		N/A		N/A

	Defined Benefit Pension Plans				OPEB Plans
WPL	2017		2016		2017		2016
Accumulated benefit obligations		$548.1		$513.2		$90.4		$88.9
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	548.1		513.2		90.4		88.9
Fair value of plan assets	415.0		389.7		18.7		18.6
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	559.8		529.2		N/A		N/A
Fair value of plan assets	415.0		389.7		N/A		N/A

Regulatory Assets

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets 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
	2017		2016		2017		2016
Regulatory assets		$38.9		$37.3		$28.1		$30.0

Estimated Future Employer Contributions

Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2018 is as follows (in millions):

	Alliant Energy		IPL		WPL
Defined benefit pension plans (a)		$6.3		$4.4		$0.3
OPEB plans	9.0		2.0		6.8

(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. In addition, IPL and WPL amounts reflect funding for their 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 for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$72.2		$73.9		$76.4		$77.1		$92.9		$398.2
OPEB	18.2		18.4		17.7		17.5		17.2		80.1
		$90.4		$92.3		$94.1		$94.6		$110.1		$478.3

IPL	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$33.9		$33.8		$36.5		$36.6		$37.6		$188.4
OPEB	7.1		7.1		7.2		7.1		7.0		32.6
		$41.0		$40.9		$43.7		$43.7		$44.6		$221.0

WPL	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$31.4		$32.0		$32.4		$32.4		$32.7		$167.8
OPEB	8.3		8.3		7.5		7.3		7.0		31.8
		$39.7		$40.3		$39.9		$39.7		$39.7		$199.6

Recognized Compensation Expense And Income Tax Benefits

A summary of compensation expense, including amounts 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
	2017		2016		2015		2017		2016		2015		2017		2016		2015
Compensation expense		$15.1		$18.0		$10.7		$8.3		$9.5		$5.7		$6.4		$7.9		$4.7
Income tax benefits	6.2		7.4		4.4		3.4		4.0		2.4		2.6		3.2		1.9

Schedule of Carrying Value and Fair Market Value of the Deferred Compensation Obligation

At December 31, the carrying value of the deferred compensation obligation for the company stock account 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):

	2017		2016
Carrying value		$11.1		$10.0
Fair market value	19.7		16.7

IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Assumptions Used To Measure Benefit Plans

The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans												OPEB Plans
Alliant Energy	2017				2016				2015				2017	2016	2015
Discount rate for benefit obligations	3.66%				4.19%				4.47%				3.53%	3.98%	4.30%
Discount rate for net periodic cost	4.19%				4.47%				4.18%				3.98%	4.30%	3.97%
Expected rate of return on plan assets	7.60%				7.60%				7.60%				5.80%	6.30%	6.20%
Rate of compensation increase	3.65	%	-	4.50%	3.65	%	-	4.50%	3.65	%	-	4.50%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A				N/A				N/A				6.75%	7.00%	7.25%
Ultimate trend rate	N/A				N/A				N/A				5.00%	5.00%	5.00%

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2017	2016	2015	2017	2016	2015
Discount rate for benefit obligations	3.68%	4.22%	4.50%	3.51%	3.95%	4.28%
Discount rate for net periodic cost	4.22%	4.50%	4.20%	3.95%	4.28%	3.94%
Expected rate of return on plan assets	7.60%	7.60%	7.60%	6.20%	6.60%	6.60%
Rate of compensation increase	3.65%	3.65%	3.65%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A	N/A	N/A	6.75%	7.00%	7.25%
Ultimate trend rate	N/A	N/A	N/A	5.00%	5.00%	5.00%

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2017	2016	2015	2017	2016	2015
Discount rate for benefit obligations	3.69%	4.23%	4.51%	3.51%	3.96%	4.28%
Discount rate for net periodic cost	4.23%	4.51%	4.20%	3.96%	4.28%	3.96%
Expected rate of return on plan assets	7.60%	7.60%	7.60%	3.50%	4.70%	4.60%
Rate of compensation increase	3.65%	3.65%	3.65%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A	N/A	N/A	6.75%	7.00%	7.25%
Ultimate trend rate	N/A	N/A	N/A	5.00%	5.00%	5.00%

Net Periodic Benefit Costs (Credits)

The components of net periodic benefit costs (credits) for sponsored defined benefit pension and OPEB plans are included in the tables below (in millions). Net periodic benefit costs are primarily included in “Other operation and maintenance” in the income statements.

Alliant Energy	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$12.5			$12.6			$15.9			$5.0			$5.3			$5.5
Interest cost	51.0			53.0			53.6			8.6			9.4			9.1
Expected return on plan assets (a)	(65.5		)	(65.5		)	(75.0		)	(6.1		)	(6.1		)	(8.4		)
Amortization of prior service credit (b)	(0.4		)	(0.3		)	(0.2		)	(0.2		)	(4.1		)	(11.3		)
Amortization of actuarial loss (c)	37.6			37.4			35.4			3.8			4.7			4.8
Additional benefit costs	—			—			0.5			—			—			—
Settlement losses (d)	0.9			—			—			—			—			—
		$36.1			$37.2			$30.2			$11.1			$9.2			($0.3	)

IPL	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$7.3			$7.5			$8.8			$2.1			$2.3			$2.4
Interest cost	23.5			24.5			25.0			3.5			3.8			3.8
Expected return on plan assets (a)	(30.8		)	(30.9		)	(35.8		)	(4.3		)	(4.3		)	(5.7		)
Amortization of prior service credit (b)	(0.2		)	(0.2		)	(0.1		)	—			(2.6		)	(6.1		)
Amortization of actuarial loss (c)	16.1			16.5			15.3			2.0			2.6			2.3
		$15.9			$17.4			$13.2			$3.3			$1.8			($3.3	)

WPL	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$4.9			$4.9			$5.8			$1.9			$2.0			$2.1
Interest cost	21.8			22.3			22.6			3.4			3.8			3.7
Expected return on plan assets (a)	(28.5		)	(28.3		)	(32.4		)	(0.8		)	(0.8		)	(1.5		)
Amortization of prior service cost (credit) (b)	0.1			0.2			0.2			(0.2		)	(0.9		)	(3.5		)
Amortization of actuarial loss (c)	18.5			17.6			16.8			1.6			1.8			2.2
Additional benefit costs	—			—			0.5			—			—			—
		$16.8			$16.7			$13.5			$5.9			$5.9			$3.0

(a) 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.

(b) Unrecognized prior service costs (credits) for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(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 where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

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

Estimated Amortization From Regulatory Assets, Regulatory Liabilities And Accumulated Other Comprehensive Loss Into Net Periodic Benefit Cost

The estimated amortization from “Regulatory assets” and “Regulatory liabilities” on the balance sheets and AOCL on Alliant Energy’s balance sheet into net periodic benefit cost in 2018 is as follows (in millions):

	Alliant Energy						IPL					WPL
	Defined Benefit						Defined Benefit					Defined Benefit
	Pension Plans			OPEB Plans			Pension Plans			OPEB Plans		Pension Plans			OPEB Plans
Actuarial loss		$35.2			$3.4			$15.0			$1.2		$17.2			$2.0
Prior service credit	(0.7		)	(0.2		)	(0.2		)	—		(0.2		)	(0.2		)
		$34.5			$3.2			$14.8			$1.2		$17.0			$1.8

Funded Status Of Benefit Plans

A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$1,244.3			$1,206.3			$220.1			$221.4
Service cost	12.5			12.6			5.0			5.3
Interest cost	51.0			53.0			8.6			9.4
Plan participants’ contributions	—			—			2.9			2.4
Actuarial (gain) loss	83.6			48.3			5.4			(0.3		)
Gross benefits paid	(88.3		)	(75.9		)	(19.7		)	(18.1		)
Net benefit obligation at December 31	1,303.1			1,244.3			222.3			220.1
Change in plan assets:
Fair value of plan assets at January 1	895.7			895.0			105.8			106.9
Actual return on plan assets	136.7			74.3			12.9			8.2
Employer contributions	6.6			2.3			9.2			6.4
Plan participants’ contributions	—			—			2.9			2.4
Gross benefits paid	(88.3		)	(75.9		)	(19.7		)	(18.1		)
Fair value of plan assets at December 31	950.7			895.7			111.1			105.8
Under funded status at December 31		($352.4	)		($348.6	)		($111.2	)		($114.3	)

	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$8.8			$3.2
Current liabilities	(2.2		)	(6.5		)	(9.1		)	(8.6		)
Pension and other benefit obligations	(350.2		)	(342.1		)	(110.9		)	(108.9		)
Net amounts recognized at December 31		($352.4	)		($348.6	)		($111.2	)		($114.3	)
Amounts recognized in Regulatory Assets (refer to Note 2 for details) and AOCL (refer to Alliant Energy’s common equity statements for details) consist of:
Net actuarial loss		$509.1			$535.1			$47.4			$52.6
Prior service credit	(6.5		)	(6.9		)	(1.3		)	(1.5		)
		$502.6			$528.2			$46.1			$51.1

	Defined Benefit Pension Plans						OPEB Plans
IPL	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$570.4			$556.1			$90.1			$91.3
Service cost	7.3			7.5			2.1			2.3
Interest cost	23.5			24.5			3.5			3.8
Plan participants’ contributions	—			—			1.0			0.9
Actuarial (gain) loss	34.9			19.1			(0.1		)	(0.7		)
Gross benefits paid	(43.2		)	(36.8		)	(7.2		)	(7.5		)
Net benefit obligation at December 31	592.9			570.4			89.4			90.1
Change in plan assets:
Fair value of plan assets at January 1	422.0			422.7			68.2			69.2
Actual return on plan assets	64.3			35.3			8.9			5.3
Employer contributions	0.6			0.8			2.0			0.3
Plan participants’ contributions	—			—			1.0			0.9
Gross benefits paid	(43.2		)	(36.8		)	(7.2		)	(7.5		)
Fair value of plan assets at December 31	443.7			422.0			72.9			68.2
Under funded status at December 31		($149.2	)		($148.4	)		($16.5	)		($21.9	)

	Defined Benefit Pension Plans						OPEB Plans
IPL	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$5.9			$0.4
Current liabilities	(0.5		)	(0.7		)	(2.0		)	(1.9		)
Pension and other benefit obligations	(148.7		)	(147.7		)	(20.4		)	(20.4		)
Net amounts recognized at December 31		($149.2	)		($148.4	)		($16.5	)		($21.9	)
Amounts recognized in Regulatory Assets consist of (refer to Note 2 for details):
Net actuarial loss		$218.9			$233.6			$18.7			$25.4
Prior service credit	(2.1		)	(2.3		)	—			—
		$216.8			$231.3			$18.7			$25.4

	Defined Benefit Pension Plans						OPEB Plans
WPL	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$529.2			$505.9			$88.9			$89.7
Service cost	4.9			4.9			1.9			2.0
Interest cost	21.8			22.3			3.4			3.8
Plan participants’ contributions	—			—			1.4			1.2
Actuarial loss	38.3			25.7			4.1			0.5
Gross benefits paid	(34.4		)	(29.6		)	(9.3		)	(8.3		)
Net benefit obligation at December 31	559.8			529.2			90.4			88.9
Change in plan assets:
Fair value of plan assets at January 1	389.7			386.8			18.6			18.7
Actual return on plan assets	59.6			32.4			1.2			1.2
Employer contributions	0.1			0.1			6.8			5.8
Plan participants’ contributions	—			—			1.4			1.2
Gross benefits paid	(34.4		)	(29.6		)	(9.3		)	(8.3		)
Fair value of plan assets at December 31	415.0			389.7			18.7			18.6
Under funded status at December 31		($144.8	)		($139.5	)		($71.7	)		($70.3	)

	Defined Benefit Pension Plans						OPEB Plans
WPL	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$2.9			$2.7
Current liabilities	(0.1		)	(0.1		)	(6.8		)	(6.4		)
Pension and other benefit obligations	(144.7		)	(139.4		)	(67.8		)	(66.6		)
Net amounts recognized at December 31		($144.8	)		($139.5	)		($71.7	)		($70.3	)
Amounts recognized in Regulatory Assets consist of (refer to Note 2 for details):
Net actuarial loss		$224.7			$236.1			$23.6			$21.5
Prior service credit	(1.5		)	(1.4		)	(1.3		)	(1.5		)
		$223.2			$234.7			$22.3			$20.0

Accumulated Benefit Obligations

Included in the following tables are accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB 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 (in millions):

	Defined Benefit Pension Plans				OPEB Plans
Alliant Energy	2017		2016		2017		2016
Accumulated benefit obligations		$1,269.0		$1,201.5		$222.3		$220.1
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,269.0		1,201.5		222.3		220.1
Fair value of plan assets	950.7		895.7		111.1		105.8
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,303.1		1,244.3		N/A		N/A
Fair value of plan assets	950.7		895.7		N/A		N/A

	Defined Benefit Pension Plans				OPEB Plans
IPL	2017		2016		2017		2016
Accumulated benefit obligations		$573.1		$546.7		$89.4		$90.1
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	573.1		546.7		89.4		90.1
Fair value of plan assets	443.7		422.0		72.9		68.2
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	592.9		570.4		N/A		N/A
Fair value of plan assets	443.7		422.0		N/A		N/A

	Defined Benefit Pension Plans				OPEB Plans
WPL	2017		2016		2017		2016
Accumulated benefit obligations		$548.1		$513.2		$90.4		$88.9
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	548.1		513.2		90.4		88.9
Fair value of plan assets	415.0		389.7		18.7		18.6
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	559.8		529.2		N/A		N/A
Fair value of plan assets	415.0		389.7		N/A		N/A

Regulatory Assets

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets 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
	2017		2016		2017		2016
Regulatory assets		$38.9		$37.3		$28.1		$30.0

Estimated Future Employer Contributions

Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2018 is as follows (in millions):

	Alliant Energy		IPL		WPL
Defined benefit pension plans (a)		$6.3		$4.4		$0.3
OPEB plans	9.0		2.0		6.8

(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. In addition, IPL and WPL amounts reflect funding for their 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 for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$72.2		$73.9		$76.4		$77.1		$92.9		$398.2
OPEB	18.2		18.4		17.7		17.5		17.2		80.1
		$90.4		$92.3		$94.1		$94.6		$110.1		$478.3

IPL	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$33.9		$33.8		$36.5		$36.6		$37.6		$188.4
OPEB	7.1		7.1		7.2		7.1		7.0		32.6
		$41.0		$40.9		$43.7		$43.7		$44.6		$221.0

WPL	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$31.4		$32.0		$32.4		$32.4		$32.7		$167.8
OPEB	8.3		8.3		7.5		7.3		7.0		31.8
		$39.7		$40.3		$39.9		$39.7		$39.7		$199.6

Recognized Compensation Expense And Income Tax Benefits

A summary of compensation expense, including amounts 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
	2017		2016		2015		2017		2016		2015		2017		2016		2015
Compensation expense		$15.1		$18.0		$10.7		$8.3		$9.5		$5.7		$6.4		$7.9		$4.7
Income tax benefits	6.2		7.4		4.4		3.4		4.0		2.4		2.6		3.2		1.9

WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Assumptions Used To Measure Benefit Plans

The assumptions for defined benefit pension and OPEB plans at the measurement date of December 31 were as follows:

	Defined Benefit Pension Plans												OPEB Plans
Alliant Energy	2017				2016				2015				2017	2016	2015
Discount rate for benefit obligations	3.66%				4.19%				4.47%				3.53%	3.98%	4.30%
Discount rate for net periodic cost	4.19%				4.47%				4.18%				3.98%	4.30%	3.97%
Expected rate of return on plan assets	7.60%				7.60%				7.60%				5.80%	6.30%	6.20%
Rate of compensation increase	3.65	%	-	4.50%	3.65	%	-	4.50%	3.65	%	-	4.50%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A				N/A				N/A				6.75%	7.00%	7.25%
Ultimate trend rate	N/A				N/A				N/A				5.00%	5.00%	5.00%

	Qualified Defined Benefit Pension Plan			OPEB Plans
IPL	2017	2016	2015	2017	2016	2015
Discount rate for benefit obligations	3.68%	4.22%	4.50%	3.51%	3.95%	4.28%
Discount rate for net periodic cost	4.22%	4.50%	4.20%	3.95%	4.28%	3.94%
Expected rate of return on plan assets	7.60%	7.60%	7.60%	6.20%	6.60%	6.60%
Rate of compensation increase	3.65%	3.65%	3.65%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A	N/A	N/A	6.75%	7.00%	7.25%
Ultimate trend rate	N/A	N/A	N/A	5.00%	5.00%	5.00%

	Qualified Defined Benefit Pension Plan			OPEB Plans
WPL	2017	2016	2015	2017	2016	2015
Discount rate for benefit obligations	3.69%	4.23%	4.51%	3.51%	3.96%	4.28%
Discount rate for net periodic cost	4.23%	4.51%	4.20%	3.96%	4.28%	3.96%
Expected rate of return on plan assets	7.60%	7.60%	7.60%	3.50%	4.70%	4.60%
Rate of compensation increase	3.65%	3.65%	3.65%	N/A	N/A	N/A
Medical cost trend on covered charges:
Initial trend rate (end of year)	N/A	N/A	N/A	6.75%	7.00%	7.25%
Ultimate trend rate	N/A	N/A	N/A	5.00%	5.00%	5.00%

Net Periodic Benefit Costs (Credits)

The components of net periodic benefit costs (credits) for sponsored defined benefit pension and OPEB plans are included in the tables below (in millions). Net periodic benefit costs are primarily included in “Other operation and maintenance” in the income statements.

Alliant Energy	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$12.5			$12.6			$15.9			$5.0			$5.3			$5.5
Interest cost	51.0			53.0			53.6			8.6			9.4			9.1
Expected return on plan assets (a)	(65.5		)	(65.5		)	(75.0		)	(6.1		)	(6.1		)	(8.4		)
Amortization of prior service credit (b)	(0.4		)	(0.3		)	(0.2		)	(0.2		)	(4.1		)	(11.3		)
Amortization of actuarial loss (c)	37.6			37.4			35.4			3.8			4.7			4.8
Additional benefit costs	—			—			0.5			—			—			—
Settlement losses (d)	0.9			—			—			—			—			—
		$36.1			$37.2			$30.2			$11.1			$9.2			($0.3	)

IPL	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$7.3			$7.5			$8.8			$2.1			$2.3			$2.4
Interest cost	23.5			24.5			25.0			3.5			3.8			3.8
Expected return on plan assets (a)	(30.8		)	(30.9		)	(35.8		)	(4.3		)	(4.3		)	(5.7		)
Amortization of prior service credit (b)	(0.2		)	(0.2		)	(0.1		)	—			(2.6		)	(6.1		)
Amortization of actuarial loss (c)	16.1			16.5			15.3			2.0			2.6			2.3
		$15.9			$17.4			$13.2			$3.3			$1.8			($3.3	)

WPL	Defined Benefit Pension Plans									OPEB Plans
	2017			2016			2015			2017			2016			2015
Service cost		$4.9			$4.9			$5.8			$1.9			$2.0			$2.1
Interest cost	21.8			22.3			22.6			3.4			3.8			3.7
Expected return on plan assets (a)	(28.5		)	(28.3		)	(32.4		)	(0.8		)	(0.8		)	(1.5		)
Amortization of prior service cost (credit) (b)	0.1			0.2			0.2			(0.2		)	(0.9		)	(3.5		)
Amortization of actuarial loss (c)	18.5			17.6			16.8			1.6			1.8			2.2
Additional benefit costs	—			—			0.5			—			—			—
		$16.8			$16.7			$13.5			$5.9			$5.9			$3.0

(a) 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.

(b) Unrecognized prior service costs (credits) for the OPEB plans are amortized over the average future service period to full eligibility of the participants of each plan.

(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 where gains or losses outside the 10% threshold are amortized over the time period the participants are expected to receive benefits.

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

Estimated Amortization From Regulatory Assets, Regulatory Liabilities And Accumulated Other Comprehensive Loss Into Net Periodic Benefit Cost

The estimated amortization from “Regulatory assets” and “Regulatory liabilities” on the balance sheets and AOCL on Alliant Energy’s balance sheet into net periodic benefit cost in 2018 is as follows (in millions):

	Alliant Energy						IPL					WPL
	Defined Benefit						Defined Benefit					Defined Benefit
	Pension Plans			OPEB Plans			Pension Plans			OPEB Plans		Pension Plans			OPEB Plans
Actuarial loss		$35.2			$3.4			$15.0			$1.2		$17.2			$2.0
Prior service credit	(0.7		)	(0.2		)	(0.2		)	—		(0.2		)	(0.2		)
		$34.5			$3.2			$14.8			$1.2		$17.0			$1.8

Funded Status Of Benefit Plans

A reconciliation of the funded status of qualified and non-qualified defined benefit pension and OPEB plans to the amounts recognized on the balance sheets at December 31 was as follows (in millions):

	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$1,244.3			$1,206.3			$220.1			$221.4
Service cost	12.5			12.6			5.0			5.3
Interest cost	51.0			53.0			8.6			9.4
Plan participants’ contributions	—			—			2.9			2.4
Actuarial (gain) loss	83.6			48.3			5.4			(0.3		)
Gross benefits paid	(88.3		)	(75.9		)	(19.7		)	(18.1		)
Net benefit obligation at December 31	1,303.1			1,244.3			222.3			220.1
Change in plan assets:
Fair value of plan assets at January 1	895.7			895.0			105.8			106.9
Actual return on plan assets	136.7			74.3			12.9			8.2
Employer contributions	6.6			2.3			9.2			6.4
Plan participants’ contributions	—			—			2.9			2.4
Gross benefits paid	(88.3		)	(75.9		)	(19.7		)	(18.1		)
Fair value of plan assets at December 31	950.7			895.7			111.1			105.8
Under funded status at December 31		($352.4	)		($348.6	)		($111.2	)		($114.3	)

	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$8.8			$3.2
Current liabilities	(2.2		)	(6.5		)	(9.1		)	(8.6		)
Pension and other benefit obligations	(350.2		)	(342.1		)	(110.9		)	(108.9		)
Net amounts recognized at December 31		($352.4	)		($348.6	)		($111.2	)		($114.3	)
Amounts recognized in Regulatory Assets (refer to Note 2 for details) and AOCL (refer to Alliant Energy’s common equity statements for details) consist of:
Net actuarial loss		$509.1			$535.1			$47.4			$52.6
Prior service credit	(6.5		)	(6.9		)	(1.3		)	(1.5		)
		$502.6			$528.2			$46.1			$51.1

	Defined Benefit Pension Plans						OPEB Plans
IPL	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$570.4			$556.1			$90.1			$91.3
Service cost	7.3			7.5			2.1			2.3
Interest cost	23.5			24.5			3.5			3.8
Plan participants’ contributions	—			—			1.0			0.9
Actuarial (gain) loss	34.9			19.1			(0.1		)	(0.7		)
Gross benefits paid	(43.2		)	(36.8		)	(7.2		)	(7.5		)
Net benefit obligation at December 31	592.9			570.4			89.4			90.1
Change in plan assets:
Fair value of plan assets at January 1	422.0			422.7			68.2			69.2
Actual return on plan assets	64.3			35.3			8.9			5.3
Employer contributions	0.6			0.8			2.0			0.3
Plan participants’ contributions	—			—			1.0			0.9
Gross benefits paid	(43.2		)	(36.8		)	(7.2		)	(7.5		)
Fair value of plan assets at December 31	443.7			422.0			72.9			68.2
Under funded status at December 31		($149.2	)		($148.4	)		($16.5	)		($21.9	)

	Defined Benefit Pension Plans						OPEB Plans
IPL	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$5.9			$0.4
Current liabilities	(0.5		)	(0.7		)	(2.0		)	(1.9		)
Pension and other benefit obligations	(148.7		)	(147.7		)	(20.4		)	(20.4		)
Net amounts recognized at December 31		($149.2	)		($148.4	)		($16.5	)		($21.9	)
Amounts recognized in Regulatory Assets consist of (refer to Note 2 for details):
Net actuarial loss		$218.9			$233.6			$18.7			$25.4
Prior service credit	(2.1		)	(2.3		)	—			—
		$216.8			$231.3			$18.7			$25.4

	Defined Benefit Pension Plans						OPEB Plans
WPL	2017			2016			2017			2016
Change in benefit obligation:
Net benefit obligation at January 1		$529.2			$505.9			$88.9			$89.7
Service cost	4.9			4.9			1.9			2.0
Interest cost	21.8			22.3			3.4			3.8
Plan participants’ contributions	—			—			1.4			1.2
Actuarial loss	38.3			25.7			4.1			0.5
Gross benefits paid	(34.4		)	(29.6		)	(9.3		)	(8.3		)
Net benefit obligation at December 31	559.8			529.2			90.4			88.9
Change in plan assets:
Fair value of plan assets at January 1	389.7			386.8			18.6			18.7
Actual return on plan assets	59.6			32.4			1.2			1.2
Employer contributions	0.1			0.1			6.8			5.8
Plan participants’ contributions	—			—			1.4			1.2
Gross benefits paid	(34.4		)	(29.6		)	(9.3		)	(8.3		)
Fair value of plan assets at December 31	415.0			389.7			18.7			18.6
Under funded status at December 31		($144.8	)		($139.5	)		($71.7	)		($70.3	)

	Defined Benefit Pension Plans						OPEB Plans
WPL	2017			2016			2017			2016
Amounts recognized on the balance sheets consist of:
Non-current assets		$—			$—			$2.9			$2.7
Current liabilities	(0.1		)	(0.1		)	(6.8		)	(6.4		)
Pension and other benefit obligations	(144.7		)	(139.4		)	(67.8		)	(66.6		)
Net amounts recognized at December 31		($144.8	)		($139.5	)		($71.7	)		($70.3	)
Amounts recognized in Regulatory Assets consist of (refer to Note 2 for details):
Net actuarial loss		$224.7			$236.1			$23.6			$21.5
Prior service credit	(1.5		)	(1.4		)	(1.3		)	(1.5		)
		$223.2			$234.7			$22.3			$20.0

Accumulated Benefit Obligations

Included in the following tables are accumulated benefit obligations, aggregate amounts applicable to defined benefit pension and OPEB 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 (in millions):

	Defined Benefit Pension Plans				OPEB Plans
Alliant Energy	2017		2016		2017		2016
Accumulated benefit obligations		$1,269.0		$1,201.5		$222.3		$220.1
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	1,269.0		1,201.5		222.3		220.1
Fair value of plan assets	950.7		895.7		111.1		105.8
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	1,303.1		1,244.3		N/A		N/A
Fair value of plan assets	950.7		895.7		N/A		N/A

	Defined Benefit Pension Plans				OPEB Plans
IPL	2017		2016		2017		2016
Accumulated benefit obligations		$573.1		$546.7		$89.4		$90.1
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	573.1		546.7		89.4		90.1
Fair value of plan assets	443.7		422.0		72.9		68.2
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	592.9		570.4		N/A		N/A
Fair value of plan assets	443.7		422.0		N/A		N/A

	Defined Benefit Pension Plans				OPEB Plans
WPL	2017		2016		2017		2016
Accumulated benefit obligations		$548.1		$513.2		$90.4		$88.9
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligations	548.1		513.2		90.4		88.9
Fair value of plan assets	415.0		389.7		18.7		18.6
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligations	559.8		529.2		N/A		N/A
Fair value of plan assets	415.0		389.7		N/A		N/A

Regulatory Assets

In addition to the amounts recognized in regulatory assets in the above tables for IPL and WPL, regulatory assets 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
	2017		2016		2017		2016
Regulatory assets		$38.9		$37.3		$28.1		$30.0

Estimated Future Employer Contributions

Estimated funding for the qualified and non-qualified defined benefit pension and OPEB plans for 2018 is as follows (in millions):

	Alliant Energy		IPL		WPL
Defined benefit pension plans (a)		$6.3		$4.4		$0.3
OPEB plans	9.0		2.0		6.8

(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. In addition, IPL and WPL amounts reflect funding for their 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 for the qualified and non-qualified defined benefit plans, which reflect expected future service, as appropriate, are as follows (in millions):

Alliant Energy	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$72.2		$73.9		$76.4		$77.1		$92.9		$398.2
OPEB	18.2		18.4		17.7		17.5		17.2		80.1
		$90.4		$92.3		$94.1		$94.6		$110.1		$478.3

IPL	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$33.9		$33.8		$36.5		$36.6		$37.6		$188.4
OPEB	7.1		7.1		7.2		7.1		7.0		32.6
		$41.0		$40.9		$43.7		$43.7		$44.6		$221.0

WPL	2018		2019		2020		2021		2022		2023 - 2027
Defined benefit pension benefits		$31.4		$32.0		$32.4		$32.4		$32.7		$167.8
OPEB	8.3		8.3		7.5		7.3		7.0		31.8
		$39.7		$40.3		$39.9		$39.7		$39.7		$199.6

Recognized Compensation Expense And Income Tax Benefits

A summary of compensation expense, including amounts 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
	2017		2016		2015		2017		2016		2015		2017		2016		2015
Compensation expense		$15.1		$18.0		$10.7		$8.3		$9.5		$5.7		$6.4		$7.9		$4.7
Income tax benefits	6.2		7.4		4.4		3.4		4.0		2.4		2.6		3.2		1.9

Pension Plans, Defined Benefit [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2017, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range				Actual
	Allocation				Allocation
Cash and equivalents	0	%	-	5%	3%
Equity securities - U.S.	11	%	-	41%	24%
Equity securities - international	14	%	-	34%	23%
Global asset securities	5	%	-	15%	10%
Risk parity securities	5	%	-	15%	10%
Fixed income securities	20	%	-	40%	30%

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
Alliant Energy	Value			1		2		3		Value			1		2		3
Cash and equivalents		$28.2			$4.5		$23.7		$—		$30.4			$5.0		$25.4		$—
Equity securities - U.S.	158.3			158.3		—		—		183.6			183.6		—		—
Equity securities - international	137.5			137.5		—		—		97.4			97.4		—		—
Global asset securities	49.4			49.4		—		—		53.0			53.0		—		—
Fixed income securities	135.9			55.8		80.1		—		125.4			53.6		71.8		—
Total assets in fair value hierarchy	509.3				$405.5		$103.8		$—	489.8				$392.6		$97.2		$—
Assets measured at net asset value	441.1									405.9
Accrued investment income	1.0									1.1
Due to brokers, net (pending trades with brokers)	(0.7		)							(1.1		)
Total pension plan assets		$950.7									$895.7

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
IPL	Value			1		2		3		Value			1		2		3
Cash and equivalents		$13.2			$2.2		$11.0		$—		$14.4			$2.4		$12.0		$—
Equity securities - U.S.	73.9			73.9		—		—		86.5			86.5		—		—
Equity securities - international	64.2			64.2		—		—		45.9			45.9		—		—
Global asset securities	23.0			23.0		—		—		24.9			24.9		—		—
Fixed income securities	63.4			26.0		37.4		—		59.1			25.3		33.8		—
Total assets in fair value hierarchy	237.7				$189.3		$48.4		$—	230.8				$185.0		$45.8		$—
Assets measured at net asset value	205.8									191.2
Accrued investment income	0.5									0.5
Due to brokers, net (pending trades with brokers)	(0.3		)							(0.5		)
Total pension plan assets		$443.7									$422.0

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
WPL	Value			1		2		3		Value			1		2		3
Cash and equivalents		$12.3			$2.0		$10.3		$—		$13.3			$2.2		$11.1		$—
Equity securities - U.S.	69.1			69.1		—		—		79.9			79.9		—		—
Equity securities - international	60.0			60.0		—		—		42.4			42.4		—		—
Global asset securities	21.6			21.6		—		—		23.0			23.0		—		—
Fixed income securities	59.3			24.3		35.0		—		54.5			23.3		31.2		—
Total assets in fair value hierarchy	222.3				$177.0		$45.3		$—	213.1				$170.8		$42.3		$—
Assets measured at net asset value	192.5									176.6
Accrued investment income	0.5									0.5
Due to brokers, net (pending trades with brokers)	(0.3		)							(0.5		)
Total pension plan assets		$415.0									$389.7

Pension Plans, Defined Benefit [Member] | IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
Alliant Energy	Value			1		2		3		Value			1		2		3
Cash and equivalents		$28.2			$4.5		$23.7		$—		$30.4			$5.0		$25.4		$—
Equity securities - U.S.	158.3			158.3		—		—		183.6			183.6		—		—
Equity securities - international	137.5			137.5		—		—		97.4			97.4		—		—
Global asset securities	49.4			49.4		—		—		53.0			53.0		—		—
Fixed income securities	135.9			55.8		80.1		—		125.4			53.6		71.8		—
Total assets in fair value hierarchy	509.3				$405.5		$103.8		$—	489.8				$392.6		$97.2		$—
Assets measured at net asset value	441.1									405.9
Accrued investment income	1.0									1.1
Due to brokers, net (pending trades with brokers)	(0.7		)							(1.1		)
Total pension plan assets		$950.7									$895.7

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
IPL	Value			1		2		3		Value			1		2		3
Cash and equivalents		$13.2			$2.2		$11.0		$—		$14.4			$2.4		$12.0		$—
Equity securities - U.S.	73.9			73.9		—		—		86.5			86.5		—		—
Equity securities - international	64.2			64.2		—		—		45.9			45.9		—		—
Global asset securities	23.0			23.0		—		—		24.9			24.9		—		—
Fixed income securities	63.4			26.0		37.4		—		59.1			25.3		33.8		—
Total assets in fair value hierarchy	237.7				$189.3		$48.4		$—	230.8				$185.0		$45.8		$—
Assets measured at net asset value	205.8									191.2
Accrued investment income	0.5									0.5
Due to brokers, net (pending trades with brokers)	(0.3		)							(0.5		)
Total pension plan assets		$443.7									$422.0

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
WPL	Value			1		2		3		Value			1		2		3
Cash and equivalents		$12.3			$2.0		$10.3		$—		$13.3			$2.2		$11.1		$—
Equity securities - U.S.	69.1			69.1		—		—		79.9			79.9		—		—
Equity securities - international	60.0			60.0		—		—		42.4			42.4		—		—
Global asset securities	21.6			21.6		—		—		23.0			23.0		—		—
Fixed income securities	59.3			24.3		35.0		—		54.5			23.3		31.2		—
Total assets in fair value hierarchy	222.3				$177.0		$45.3		$—	213.1				$170.8		$42.3		$—
Assets measured at net asset value	192.5									176.6
Accrued investment income	0.5									0.5
Due to brokers, net (pending trades with brokers)	(0.3		)							(0.5		)
Total pension plan assets		$415.0									$389.7

At December 31, 2017, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range				Actual
	Allocation				Allocation
Cash and equivalents	0	%	-	5%	3%
Equity securities - U.S.	11	%	-	41%	24%
Equity securities - international	14	%	-	34%	23%
Global asset securities	5	%	-	15%	10%
Risk parity securities	5	%	-	15%	10%
Fixed income securities	20	%	-	40%	30%

Pension Plans, Defined Benefit [Member] | WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2017, the current target ranges and actual allocations for the defined benefit pension plan assets were as follows:

	Target Range				Actual
	Allocation				Allocation
Cash and equivalents	0	%	-	5%	3%
Equity securities - U.S.	11	%	-	41%	24%
Equity securities - international	14	%	-	34%	23%
Global asset securities	5	%	-	15%	10%
Risk parity securities	5	%	-	15%	10%
Fixed income securities	20	%	-	40%	30%

At December 31, the fair values of qualified and non-qualified defined benefit pension plan assets were as follows (in millions):

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
Alliant Energy	Value			1		2		3		Value			1		2		3
Cash and equivalents		$28.2			$4.5		$23.7		$—		$30.4			$5.0		$25.4		$—
Equity securities - U.S.	158.3			158.3		—		—		183.6			183.6		—		—
Equity securities - international	137.5			137.5		—		—		97.4			97.4		—		—
Global asset securities	49.4			49.4		—		—		53.0			53.0		—		—
Fixed income securities	135.9			55.8		80.1		—		125.4			53.6		71.8		—
Total assets in fair value hierarchy	509.3				$405.5		$103.8		$—	489.8				$392.6		$97.2		$—
Assets measured at net asset value	441.1									405.9
Accrued investment income	1.0									1.1
Due to brokers, net (pending trades with brokers)	(0.7		)							(1.1		)
Total pension plan assets		$950.7									$895.7

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
IPL	Value			1		2		3		Value			1		2		3
Cash and equivalents		$13.2			$2.2		$11.0		$—		$14.4			$2.4		$12.0		$—
Equity securities - U.S.	73.9			73.9		—		—		86.5			86.5		—		—
Equity securities - international	64.2			64.2		—		—		45.9			45.9		—		—
Global asset securities	23.0			23.0		—		—		24.9			24.9		—		—
Fixed income securities	63.4			26.0		37.4		—		59.1			25.3		33.8		—
Total assets in fair value hierarchy	237.7				$189.3		$48.4		$—	230.8				$185.0		$45.8		$—
Assets measured at net asset value	205.8									191.2
Accrued investment income	0.5									0.5
Due to brokers, net (pending trades with brokers)	(0.3		)							(0.5		)
Total pension plan assets		$443.7									$422.0

	2017									2016
	Fair			Level		Level		Level		Fair			Level		Level		Level
WPL	Value			1		2		3		Value			1		2		3
Cash and equivalents		$12.3			$2.0		$10.3		$—		$13.3			$2.2		$11.1		$—
Equity securities - U.S.	69.1			69.1		—		—		79.9			79.9		—		—
Equity securities - international	60.0			60.0		—		—		42.4			42.4		—		—
Global asset securities	21.6			21.6		—		—		23.0			23.0		—		—
Fixed income securities	59.3			24.3		35.0		—		54.5			23.3		31.2		—
Total assets in fair value hierarchy	222.3				$177.0		$45.3		$—	213.1				$170.8		$42.3		$—
Assets measured at net asset value	192.5									176.6
Accrued investment income	0.5									0.5
Due to brokers, net (pending trades with brokers)	(0.3		)							(0.5		)
Total pension plan assets		$415.0									$389.7

Other Postretirement Benefits Plans [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2017, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range				Actual
	Allocation				Allocation
Cash and equivalents	0	%	-	5%	1%
Equity securities - U.S.	0	%	-	50%	26%
Equity securities - international	0	%	-	34%	10%
Fixed income securities	20	%	-	100%	63%

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
Alliant Energy	Value		1		2		3		Value		1		2		3
Cash and equivalents		$1.2		$0.7		$0.5		$—		$3.5		$2.0		$1.5		$—
Equity securities - U.S.	27.9		27.9		—		—		22.5		22.5		—		—
Equity securities - international	11.4		11.4		—		—		13.5		13.5		—		—
Global asset securities	0.4		0.4		—		—		16.5		16.5		—		—
Fixed income securities	66.6		66.0		0.6		—		46.8		46.2		0.6		—
Total assets in fair value hierarchy	107.5			$106.4		$1.1		$—	102.8			$100.7		$2.1		$—
Assets measured at net asset value	3.6								3.0
Total OPEB plan assets		$111.1								$105.8

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
IPL	Value		1		2		3		Value		1		2		3
Cash and equivalents		$0.3		$0.3		$—		$—		$0.8		$0.8		$—		$—
Equity securities - U.S.	22.3		22.3		—		—		17.0		17.0		—		—
Equity securities - international	7.5		7.5		—		—		11.0		11.0		—		—
Global asset securities	—		—		—		—		7.0		7.0		—		—
Fixed income securities	42.8		42.8		—		—		32.4		32.4		—		—
Total OPEB plan assets		$72.9		$72.9		$—		$—		$68.2		$68.2		$—		$—

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
WPL	Value		1		2		3		Value		1		2		3
Cash and equivalents		$0.6		$0.3		$0.3		$—		$2.0		$0.7		$1.3		$—
Global asset securities	—		—		—		—		5.5		5.5		—		—
Fixed income securities	18.1		18.1		—		—		11.1		11.1		—		—
Total OPEB plan assets		$18.7		$18.4		$0.3		$—		$18.6		$17.3		$1.3		$—

Other Postretirement Benefits Plans [Member] | IPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, 2017, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range				Actual
	Allocation				Allocation
Cash and equivalents	0	%	-	5%	1%
Equity securities - U.S.	0	%	-	50%	26%
Equity securities - international	0	%	-	34%	10%
Fixed income securities	20	%	-	100%	63%

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
Alliant Energy	Value		1		2		3		Value		1		2		3
Cash and equivalents		$1.2		$0.7		$0.5		$—		$3.5		$2.0		$1.5		$—
Equity securities - U.S.	27.9		27.9		—		—		22.5		22.5		—		—
Equity securities - international	11.4		11.4		—		—		13.5		13.5		—		—
Global asset securities	0.4		0.4		—		—		16.5		16.5		—		—
Fixed income securities	66.6		66.0		0.6		—		46.8		46.2		0.6		—
Total assets in fair value hierarchy	107.5			$106.4		$1.1		$—	102.8			$100.7		$2.1		$—
Assets measured at net asset value	3.6								3.0
Total OPEB plan assets		$111.1								$105.8

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
IPL	Value		1		2		3		Value		1		2		3
Cash and equivalents		$0.3		$0.3		$—		$—		$0.8		$0.8		$—		$—
Equity securities - U.S.	22.3		22.3		—		—		17.0		17.0		—		—
Equity securities - international	7.5		7.5		—		—		11.0		11.0		—		—
Global asset securities	—		—		—		—		7.0		7.0		—		—
Fixed income securities	42.8		42.8		—		—		32.4		32.4		—		—
Total OPEB plan assets		$72.9		$72.9		$—		$—		$68.2		$68.2		$—		$—

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
WPL	Value		1		2		3		Value		1		2		3
Cash and equivalents		$0.6		$0.3		$0.3		$—		$2.0		$0.7		$1.3		$—
Global asset securities	—		—		—		—		5.5		5.5		—		—
Fixed income securities	18.1		18.1		—		—		11.1		11.1		—		—
Total OPEB plan assets		$18.7		$18.4		$0.3		$—		$18.6		$17.3		$1.3		$—

Other Postretirement Benefits Plans [Member] | WPL [Member]

Defined Benefit Plan Disclosure [Line Items]

Fair Value Of Plan Assets By Asset Category, Fair Value Hierarchy Level and Allocations

At December 31, the fair values of OPEB plan assets were as follows (in millions):

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
Alliant Energy	Value		1		2		3		Value		1		2		3
Cash and equivalents		$1.2		$0.7		$0.5		$—		$3.5		$2.0		$1.5		$—
Equity securities - U.S.	27.9		27.9		—		—		22.5		22.5		—		—
Equity securities - international	11.4		11.4		—		—		13.5		13.5		—		—
Global asset securities	0.4		0.4		—		—		16.5		16.5		—		—
Fixed income securities	66.6		66.0		0.6		—		46.8		46.2		0.6		—
Total assets in fair value hierarchy	107.5			$106.4		$1.1		$—	102.8			$100.7		$2.1		$—
Assets measured at net asset value	3.6								3.0
Total OPEB plan assets		$111.1								$105.8

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
IPL	Value		1		2		3		Value		1		2		3
Cash and equivalents		$0.3		$0.3		$—		$—		$0.8		$0.8		$—		$—
Equity securities - U.S.	22.3		22.3		—		—		17.0		17.0		—		—
Equity securities - international	7.5		7.5		—		—		11.0		11.0		—		—
Global asset securities	—		—		—		—		7.0		7.0		—		—
Fixed income securities	42.8		42.8		—		—		32.4		32.4		—		—
Total OPEB plan assets		$72.9		$72.9		$—		$—		$68.2		$68.2		$—		$—

	2017								2016
	Fair		Level		Level		Level		Fair		Level		Level		Level
WPL	Value		1		2		3		Value		1		2		3
Cash and equivalents		$0.6		$0.3		$0.3		$—		$2.0		$0.7		$1.3		$—
Global asset securities	—		—		—		—		5.5		5.5		—		—
Fixed income securities	18.1		18.1		—		—		11.1		11.1		—		—
Total OPEB plan assets		$18.7		$18.4		$0.3		$—		$18.6		$17.3		$1.3		$—

At December 31, 2017, the current target ranges and actual allocations for VEBA trusts with assets greater than $5 million and the WPL 401(h) assets were as follows:

	Target Range				Actual
	Allocation				Allocation
Cash and equivalents	0	%	-	5%	1%
Equity securities - U.S.	0	%	-	50%	26%
Equity securities - international	0	%	-	34%	10%
Fixed income securities	20	%	-	100%	63%

401(k) Savings Plan [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’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy						IPL						WPL
	2017		2016		2015		2017		2016		2015		2017		2016		2015
401(k) costs		$24.8		$23.6		$24.9		$12.8		$12.0		$12.7		$11.1		$10.7		$11.2

401(k) Savings Plan [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’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy						IPL						WPL
	2017		2016		2015		2017		2016		2015		2017		2016		2015
401(k) costs		$24.8		$23.6		$24.9		$12.8		$12.0		$12.7		$11.1		$10.7		$11.2

401(k) Savings Plan [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’ contributions and include allocated costs associated with Corporate Services employees for IPL and WPL, were as follows (in millions):

	Alliant Energy						IPL						WPL
	2017		2016		2015		2017		2016		2015		2017		2016		2015
401(k) costs		$24.8		$23.6		$24.9		$12.8		$12.0		$12.7		$11.1		$10.7		$11.2

Performance Shares and Performance Units [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of the performance shares and performance units activity, with amounts representing the target number of awards, was as follows:

	Performance Shares						Performance Units
	2017		2016		2015		2017		2016		2015
Nonvested awards, January 1	257,599		288,430		288,848		93,320		116,412		127,330
Granted	65,350		68,585		90,806		21,558		23,918		35,674
Vested	(99,438	)	(98,186	)	(91,224	)	(37,395	)	(42,760	)	(45,690	)
Forfeited	—		(1,230	)	—		(5,746	)	(4,250	)	(902	)
Nonvested awards, December 31	223,511		257,599		288,430		71,737		93,320		116,412

Granted Awards - Each performance share’s value is based on the closing market price of one share of Alliant Energy’s common stock at the end of the performance period. For performance units granted in 2017 and 2016, the value is based on the closing market price of one share of Alliant Energy’s common stock at the end of the performance period. For performance units granted in 2015, the value is based on the closing market price of one share of Alliant Energy’s common stock on the grant date of the award. The actual payout for performance shares and performance units is dependent upon actual performance and may range from zero to 200% of the target number of awards. Compensation expense for performance shares and performance units is recorded ratably over the performance period based on the fair value of the awards at each reporting period.

Vested Awards - Certain performance shares and performance units 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
	2017	2016	2015	2017	2016	2015
	2014 Grant	2013 Grant	2012 Grant	2014 Grant	2013 Grant	2012 Grant
Performance awards vested	99,438	98,186	91,224	37,395	42,760	45,690
Percentage of target number of performance awards	147.5%	165.0%	167.5%	147.5%	165.0%	167.5%
Aggregate payout value (in millions)	$5.6	$5.1	$5.1	$1.5	$1.7	$1.6
Payout - cash (in millions)	$5.1	$2.9	$3.2	$1.5	$1.7	$1.6
Payout - common stock shares issued	5,185	22,408	21,950	N/A	N/A	N/A

Fair Value of Awards - Information related to fair values of nonvested performance shares and performance units at December 31, 2017, by year of grant, were as follows:

	Performance Shares									Performance Units
	2017 Grant			2016 Grant			2015 Grant			2017 Grant			2016 Grant			2015 Grant
Nonvested awards at target	65,350			67,355			90,806			18,600			21,227			31,910
Alliant Energy common stock closing price on December 29, 2017		$42.61			$42.61			$42.61			$42.61			$42.61		N/A
Alliant Energy common stock closing price on grant date	N/A			N/A			N/A			N/A			N/A				$32.55
Estimated payout percentage based on performance criteria	105		%	150		%	138		%	105		%	150		%	138		%
Fair values of each nonvested award		$44.74			$63.92			$58.80			$44.74			$63.92			$44.92

Performance Restricted Stock Unit [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of the performance restricted stock units activity, with amounts representing the target number of units, was as follows:

	2017			2016
	Units	Weighted Average Grant Date Fair Value		Units		Weighted Average Grant Date Fair Value
Nonvested units, January 1	67,355		$33.96	—			$—
Granted	65,350	39.12		68,585		33.96
Forfeited	—	—		(1,230	)	33.90
Nonvested units, December 31	132,705	36.50		67,355		33.96

Restricted Stock Units [Member]

Defined Benefit Plan Disclosure [Line Items]

Schedule Of Equity-based Compensation Plans Activity

A summary of the restricted stock units activity was as follows:

	2017	2016
Nonvested units, January 1	57,736	—
Granted	56,013	58,790
Forfeited	—	(1,054	)
Nonvested units, December 31	113,749	57,736