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v3.22.1

Fair Value Measurements (Fair Value Measurements) (Details) - USD ($) $ in Millions | Mar. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Assets: |  |
Money market fund investments | $ 59 | $ 32
Deferred proceeds | 227 | 214
Liabilities: |  |
Long-term debt (incl. current maturities) | 7,972 | 8,330
IPL [Member] |  |
Assets: |  |
Money market fund investments | 59 | 32
Deferred proceeds | 227 | 214
Liabilities: |  |
Long-term debt (incl. current maturities) | 3,738 | 4,124
WPL [Member] |  |
Liabilities: |  |
Long-term debt (incl. current maturities) | 2,592 | 2,862
Commodity Contracts [Member] |  |
Assets: |  |
Derivatives | 261 | 176
Liabilities: |  |
Derivatives | 7 | 9
Commodity Contracts [Member] | IPL [Member] |  |
Assets: |  |
Derivatives | 127 | 84
Liabilities: |  |
Derivatives | 4 | 4
Commodity Contracts [Member] | WPL [Member] |  |
Assets: |  |
Derivatives | 134 | 92
Liabilities: |  |
Derivatives | 3 | 5
Level 1 [Member] |  |
Assets: |  |
Money market fund investments | 59 | 32
Deferred proceeds | 0 | 0
Liabilities: |  |
Long-term debt (incl. current maturities) | 0 | 0
Level 1 [Member] | IPL [Member] |  |
Assets: |  |
Money market fund investments | 59 | 32
Deferred proceeds | 0 | 0
Liabilities: |  |
Long-term debt (incl. current maturities) | 0 | 0
Level 1 [Member] | WPL [Member] |  |
Liabilities: |  |
Long-term debt (incl. current maturities) | 0 | 0
Level 1 [Member] | Commodity Contracts [Member] |  |
Assets: |  |
Derivatives | 0 | 0
Liabilities: |  |
Derivatives | 0 | 0
Level 1 [Member] | Commodity Contracts [Member] | IPL [Member] |  |
Assets: |  |
Derivatives | 0 | 0
Liabilities: |  |
Derivatives | 0 | 0
Level 1 [Member] | Commodity Contracts [Member] | WPL [Member] |  |
Assets: |  |
Derivatives | 0 | 0
Liabilities: |  |
Derivatives | 0 | 0
Level 2 [Member] |  |
Assets: |  |
Money market fund investments | 0 | 0
Deferred proceeds | 0 | 0
Liabilities: |  |
Long-term debt (incl. current maturities) | 7,971 | 8,329
Level 2 [Member] | IPL [Member] |  |
Assets: |  |
Money market fund investments | 0 | 0
Deferred proceeds | 0 | 0
Liabilities: |  |
Long-term debt (incl. current maturities) | 3,738 | 4,124
Level 2 [Member] | WPL [Member] |  |
Liabilities: |  |
Long-term debt (incl. current maturities) | 2,592 | 2,862
Level 2 [Member] | Commodity Contracts [Member] |  |
Assets: |  |
Derivatives | 251 | 146
Liabilities: |  |
Derivatives | 7 | 8
Level 2 [Member] | Commodity Contracts [Member] | IPL [Member] |  |
Assets: |  |
Derivatives | 120 | 65
Liabilities: |  |
Derivatives | 4 | 3
Level 2 [Member] | Commodity Contracts [Member] | WPL [Member] |  |
Assets: |  |
Derivatives | 131 | 81
Liabilities: |  |
Derivatives | 3 | 5
Level 3 [Member] |  |
Assets: |  |
Money market fund investments | 0 | 0
Deferred proceeds | 227 | 214
Liabilities: |  |
Long-term debt (incl. current maturities) | 1 | 1
Level 3 [Member] | IPL [Member] |  |
Assets: |  |
Money market fund investments | 0 | 0
Deferred proceeds | 227 | 214
Liabilities: |  |
Long-term debt (incl. current maturities) | 0 | 0
Level 3 [Member] | WPL [Member] |  |
Liabilities: |  |
Long-term debt (incl. current maturities) | 0 | 0
Level 3 [Member] | Commodity Contracts [Member] |  |
Assets: |  |
Derivatives | 10 | 30
Liabilities: |  |
Derivatives | 0 | 1
Level 3 [Member] | Commodity Contracts [Member] | IPL [Member] |  |
Assets: |  |
Derivatives | 7 | 19
Liabilities: |  |
Derivatives | 0 | 1
Level 3 [Member] | Commodity Contracts [Member] | WPL [Member] |  |
Assets: |  |
Derivatives | 3 | 11
Liabilities: |  |
Derivatives | 0 | 0
Carrying Amount [Member] |  |
Assets: |  |
Money market fund investments | 59 | 32
Deferred proceeds | 227 | 214
Liabilities: |  |
Long-term debt (incl. current maturities) | 7,716 | 7,368
Carrying Amount [Member] | IPL [Member] |  |
Assets: |  |
Money market fund investments | 59 | 32
Deferred proceeds | 227 | 214
Liabilities: |  |
Long-term debt (incl. current maturities) | 3,644 | 3,643
Carrying Amount [Member] | WPL [Member] |  |
Liabilities: |  |
Long-term debt (incl. current maturities) | 2,430 | 2,429
Carrying Amount [Member] | Commodity Contracts [Member] |  |
Assets: |  |
Derivatives | 261 | 176
Liabilities: |  |
Derivatives | 7 | 9
Carrying Amount [Member] | Commodity Contracts [Member] | IPL [Member] |  |
Assets: |  |
Derivatives | 127 | 84
Liabilities: |  |
Derivatives | 4 | 4
Carrying Amount [Member] | Commodity Contracts [Member] | WPL [Member] |  |
Assets: |  |
Derivatives | 134 | 92
Liabilities: |  |
Derivatives | $ 3 | $ 5

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