v3.25.2
Benefit Plans (Tables)
 6 Months Ended
Jun. 30, 2025
Defined Benefit Plan Disclosure [Line Items]  
Net Periodic Benefit Costs The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
Alliant Energy20252024202520242025202420252024
Service cost$1$1$2$2$1$1$1$1
Interest cost121123222244
Expected return on plan assets(14)(14)(27)(27)(2)(1)(3)(2)
Amortization of actuarial loss561112————
$4$4$9$9$1$2$2$3
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
IPL20252024202520242025202420252024
Service cost$—$—$1$1$—$—$—$—
Interest cost5510101122
Expected return on plan assets(6)(6)(12)(13)(1)(1)(2)(2)
Amortization of actuarial loss2345————
$1$2$3$3$—$—$—$—
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
WPL20252024202520242025202420252024
Service cost$1$1$1$1$—$—$—$—
Interest cost551010—112
Expected return on plan assets(6)(6)(12)(12)————
Amortization of actuarial loss2356————
$2$3$4$5$—$1$1$2
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 for the three and six months ended June 30 was as follows (in millions):
Alliant EnergyIPLWPL
Three MonthsSix Months Three MonthsSix Months Three MonthsSix Months
202520242025202420252024202520242025202420252024
Compensation expense$3$3$7$7$2$2$4$4$1$1$3$3
Income tax benefits1122——11——11
Schedule Of Equity-based Compensation Plans Activity
For the six months ended June 30, 2025, performance shares and restricted stock units were granted to key employees under the equity-based compensation plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.
Weighted Average
GrantsGrant Date Fair Value
Performance shares (total shareowner return metric)105,523$66.51
Performance shares (net income and environmental metrics)118,45761.61
Restricted stock units98,82161.62
IPL [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Net Periodic Benefit Costs The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
Alliant Energy20252024202520242025202420252024
Service cost$1$1$2$2$1$1$1$1
Interest cost121123222244
Expected return on plan assets(14)(14)(27)(27)(2)(1)(3)(2)
Amortization of actuarial loss561112————
$4$4$9$9$1$2$2$3
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
IPL20252024202520242025202420252024
Service cost$—$—$1$1$—$—$—$—
Interest cost5510101122
Expected return on plan assets(6)(6)(12)(13)(1)(1)(2)(2)
Amortization of actuarial loss2345————
$1$2$3$3$—$—$—$—
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
WPL20252024202520242025202420252024
Service cost$1$1$1$1$—$—$—$—
Interest cost551010—112
Expected return on plan assets(6)(6)(12)(12)————
Amortization of actuarial loss2356————
$2$3$4$5$—$1$1$2
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 for the three and six months ended June 30 was as follows (in millions):
Alliant EnergyIPLWPL
Three MonthsSix Months Three MonthsSix Months Three MonthsSix Months
202520242025202420252024202520242025202420252024
Compensation expense$3$3$7$7$2$2$4$4$1$1$3$3
Income tax benefits1122——11——11
Schedule Of Equity-based Compensation Plans Activity
For the six months ended June 30, 2025, performance shares and restricted stock units were granted to key employees under the equity-based compensation plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.
Weighted Average
GrantsGrant Date Fair Value
Performance shares (total shareowner return metric)105,523$66.51
Performance shares (net income and environmental metrics)118,45761.61
Restricted stock units98,82161.62
WPL [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Net Periodic Benefit Costs The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
Alliant Energy20252024202520242025202420252024
Service cost$1$1$2$2$1$1$1$1
Interest cost121123222244
Expected return on plan assets(14)(14)(27)(27)(2)(1)(3)(2)
Amortization of actuarial loss561112————
$4$4$9$9$1$2$2$3
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
IPL20252024202520242025202420252024
Service cost$—$—$1$1$—$—$—$—
Interest cost5510101122
Expected return on plan assets(6)(6)(12)(13)(1)(1)(2)(2)
Amortization of actuarial loss2345————
$1$2$3$3$—$—$—$—
Defined Benefit Pension PlansOPEB Plans
Three MonthsSix MonthsThree MonthsSix Months
WPL20252024202520242025202420252024
Service cost$1$1$1$1$—$—$—$—
Interest cost551010—112
Expected return on plan assets(6)(6)(12)(12)————
Amortization of actuarial loss2356————
$2$3$4$5$—$1$1$2
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 for the three and six months ended June 30 was as follows (in millions):
Alliant EnergyIPLWPL
Three MonthsSix Months Three MonthsSix Months Three MonthsSix Months
202520242025202420252024202520242025202420252024
Compensation expense$3$3$7$7$2$2$4$4$1$1$3$3
Income tax benefits1122——11——11
Schedule Of Equity-based Compensation Plans Activity
For the six months ended June 30, 2025, performance shares and restricted stock units were granted to key employees under the equity-based compensation plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards.
Weighted Average
GrantsGrant Date Fair Value
Performance shares (total shareowner return metric)105,523$66.51
Performance shares (net income and environmental metrics)118,45761.61
Restricted stock units98,82161.62