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Benefit Plans | 3 Months Ended
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Mar. 31, 2021
Benefit Plans | BENEFIT PLANS NOTE 9(a) Pension and OPEB Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 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 Plans |  | OPEB Plans
Alliant Energy | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $3 |  | $3 |  |  |  |  |  | $1 |  | $1 |  |  |  |
Interest cost | 8 |  | 11 |  |  |  |  |  | 1 |  | 2 |  |  |  |
Expected return on plan assets | (17) |  | (18) |  |  |  |  |  | (1) |  | (2) |  |  |  |
Amortization of actuarial loss | 10 |  | 9 |  |  |  |  |  | 1 |  | 1 |  |  |  |
Settlement losses (a) | — |  | 4 |  |  |  |  |  | — |  | — |  |  |  |
| $4 |  | $9 |  |  |  |  |  | $2 |  | $2 |  |  |  |
| Defined Benefit Pension Plans |  | OPEB Plans
IPL | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $2 |  | $1 |  |  |  |  |  | $— |  | $— |  |  |  |
Interest cost | 4 |  | 5 |  |  |  |  |  | 1 |  | 1 |  |  |  |
Expected return on plan assets | (8) |  | (8) |  |  |  |  |  | (1) |  | (1) |  |  |  |
Amortization of actuarial loss | 4 |  | 4 |  |  |  |  |  | — |  | — |  |  |  |
| $2 |  | $2 |  |  |  |  |  | $— |  | $— |  |  |  |
| Defined Benefit Pension Plans |  | OPEB Plans
WPL | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $1 |  | $1 |  |  |  |  |  | $— |  | $— |  |  |  |
Interest cost | 4 |  | 5 |  |  |  |  |  | — |  | 1 |  |  |  |
Expected return on plan assets | (8) |  | (8) |  |  |  |  |  | — |  | — |  |  |  |
Amortization of actuarial loss | 5 |  | 4 |  |  |  |  |  | 1 |  | — |  |  |  |
| $2 |  | $2 |  |  |  |  |  | $1 |  | $1 |  |  |  |
(a)Settlement losses related to payments made to retired executives of Alliant Energy. NOTE 9(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 months ended March 31 was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Compensation expense | $3 |  |  | $3 |  |  |  |  |  |  | $1 |  |  | $1 |  |  |  |  |  |  | $1 |  |  | $1 |  |  |  |  |
Income tax benefits | 1 |  |  | 1 |  |  |  |  |  |  | — |  |  | — |  |  |  |  |  |  | — |  |  | — |  |  |  |  |
As of March 31, 2021, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $13 million, $7 million and $5 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years. For the three months ended March 31, 2021, performance shares, performance restricted stock units and restricted stock units were granted to key employees 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
| Grants |  | Grant Date Fair Value
Performance shares | 72,774 |  | $46.19
Performance restricted stock units | 72,774 |  | 48.61
Restricted stock units | 79,862 |  | 48.61
As of March 31, 2021, 425,849 shares were included in the calculation of diluted EPS related to the nonvested equity awards.
IPL [Member] |
Benefit Plans | BENEFIT PLANS NOTE 9(a) Pension and OPEB Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 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 Plans |  | OPEB Plans
Alliant Energy | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $3 |  | $3 |  |  |  |  |  | $1 |  | $1 |  |  |  |
Interest cost | 8 |  | 11 |  |  |  |  |  | 1 |  | 2 |  |  |  |
Expected return on plan assets | (17) |  | (18) |  |  |  |  |  | (1) |  | (2) |  |  |  |
Amortization of actuarial loss | 10 |  | 9 |  |  |  |  |  | 1 |  | 1 |  |  |  |
Settlement losses (a) | — |  | 4 |  |  |  |  |  | — |  | — |  |  |  |
| $4 |  | $9 |  |  |  |  |  | $2 |  | $2 |  |  |  |
| Defined Benefit Pension Plans |  | OPEB Plans
IPL | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $2 |  | $1 |  |  |  |  |  | $— |  | $— |  |  |  |
Interest cost | 4 |  | 5 |  |  |  |  |  | 1 |  | 1 |  |  |  |
Expected return on plan assets | (8) |  | (8) |  |  |  |  |  | (1) |  | (1) |  |  |  |
Amortization of actuarial loss | 4 |  | 4 |  |  |  |  |  | — |  | — |  |  |  |
| $2 |  | $2 |  |  |  |  |  | $— |  | $— |  |  |  |
| Defined Benefit Pension Plans |  | OPEB Plans
WPL | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $1 |  | $1 |  |  |  |  |  | $— |  | $— |  |  |  |
Interest cost | 4 |  | 5 |  |  |  |  |  | — |  | 1 |  |  |  |
Expected return on plan assets | (8) |  | (8) |  |  |  |  |  | — |  | — |  |  |  |
Amortization of actuarial loss | 5 |  | 4 |  |  |  |  |  | 1 |  | — |  |  |  |
| $2 |  | $2 |  |  |  |  |  | $1 |  | $1 |  |  |  |
(a)Settlement losses related to payments made to retired executives of Alliant Energy. NOTE 9(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 months ended March 31 was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Compensation expense | $3 |  |  | $3 |  |  |  |  |  |  | $1 |  |  | $1 |  |  |  |  |  |  | $1 |  |  | $1 |  |  |  |  |
Income tax benefits | 1 |  |  | 1 |  |  |  |  |  |  | — |  |  | — |  |  |  |  |  |  | — |  |  | — |  |  |  |  |
As of March 31, 2021, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $13 million, $7 million and $5 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years. For the three months ended March 31, 2021, performance shares, performance restricted stock units and restricted stock units were granted to key employees 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
| Grants |  | Grant Date Fair Value
Performance shares | 72,774 |  | $46.19
Performance restricted stock units | 72,774 |  | 48.61
Restricted stock units | 79,862 |  | 48.61
As of March 31, 2021, 425,849 shares were included in the calculation of diluted EPS related to the nonvested equity awards.
WPL [Member] |
Benefit Plans | BENEFIT PLANS NOTE 9(a) Pension and OPEB Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 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 Plans |  | OPEB Plans
Alliant Energy | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $3 |  | $3 |  |  |  |  |  | $1 |  | $1 |  |  |  |
Interest cost | 8 |  | 11 |  |  |  |  |  | 1 |  | 2 |  |  |  |
Expected return on plan assets | (17) |  | (18) |  |  |  |  |  | (1) |  | (2) |  |  |  |
Amortization of actuarial loss | 10 |  | 9 |  |  |  |  |  | 1 |  | 1 |  |  |  |
Settlement losses (a) | — |  | 4 |  |  |  |  |  | — |  | — |  |  |  |
| $4 |  | $9 |  |  |  |  |  | $2 |  | $2 |  |  |  |
| Defined Benefit Pension Plans |  | OPEB Plans
IPL | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $2 |  | $1 |  |  |  |  |  | $— |  | $— |  |  |  |
Interest cost | 4 |  | 5 |  |  |  |  |  | 1 |  | 1 |  |  |  |
Expected return on plan assets | (8) |  | (8) |  |  |  |  |  | (1) |  | (1) |  |  |  |
Amortization of actuarial loss | 4 |  | 4 |  |  |  |  |  | — |  | — |  |  |  |
| $2 |  | $2 |  |  |  |  |  | $— |  | $— |  |  |  |
| Defined Benefit Pension Plans |  | OPEB Plans
WPL | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Service cost | $1 |  | $1 |  |  |  |  |  | $— |  | $— |  |  |  |
Interest cost | 4 |  | 5 |  |  |  |  |  | — |  | 1 |  |  |  |
Expected return on plan assets | (8) |  | (8) |  |  |  |  |  | — |  | — |  |  |  |
Amortization of actuarial loss | 5 |  | 4 |  |  |  |  |  | 1 |  | — |  |  |  |
| $2 |  | $2 |  |  |  |  |  | $1 |  | $1 |  |  |  |
(a)Settlement losses related to payments made to retired executives of Alliant Energy. NOTE 9(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 months ended March 31 was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |  |  | 2021 |  | 2020 |  |  |  |
Compensation expense | $3 |  |  | $3 |  |  |  |  |  |  | $1 |  |  | $1 |  |  |  |  |  |  | $1 |  |  | $1 |  |  |  |  |
Income tax benefits | 1 |  |  | 1 |  |  |  |  |  |  | — |  |  | — |  |  |  |  |  |  | — |  |  | — |  |  |  |  |
As of March 31, 2021, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $13 million, $7 million and $5 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years. For the three months ended March 31, 2021, performance shares, performance restricted stock units and restricted stock units were granted to key employees 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
| Grants |  | Grant Date Fair Value
Performance shares | 72,774 |  | $46.19
Performance restricted stock units | 72,774 |  | 48.61
Restricted stock units | 79,862 |  | 48.61
As of March 31, 2021, 425,849 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

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- Definition The entire disclosure for an entity's employee compensation and benefit plans, including, but not limited to, postemployment and postretirement benefit plans, defined benefit pension plans, defined contribution plans, non-qualified and supplemental benefit plans, deferred compensation, share-based compensation, life insurance, severance, health care, unemployment and other benefit plans. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -URI http://asc.fasb.org/topic&trid=2228938 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 712 -URI http://asc.fasb.org/topic&trid=2197446 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -URI http://asc.fasb.org/topic&trid=2127225 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -URI http://asc.fasb.org/topic&trid=2235017 + Details
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