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Benefit Plans (Amounts Recognized On The Consolidated Balance Sheets) (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
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Amounts recognized on the balance sheets consist of: |  |
Pension and other benefit obligations | $ (374) | $ (511)
Pension Plans, Defined Benefit [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Non-current assets | 0 | 0
Current liabilities | (2) | (2)
Pension and other benefit obligations | (238) | (365)
Net amounts recognized at December 31 | (240) | (367)
Amounts recognized in Regulatory Assets consist of: |  |
Net actuarial loss | 429 | 533
Prior service credit | (4) | (5)
Net amount recognized at December 31 | 425 | 528
Other Postretirement Benefits Plans [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Non-current assets | 13 | 8
Current liabilities | (8) | (8)
Pension and other benefit obligations | (109) | (119)
Net amounts recognized at December 31 | (104) | (119)
Amounts recognized in Regulatory Assets consist of: |  |
Net actuarial loss | 38 | 54
Prior service credit | (1) | (1)
Net amount recognized at December 31 | 37 | 53
IPL [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Pension and other benefit obligations | (127) | (186)
IPL [Member] | Pension Plans, Defined Benefit [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Non-current assets | 0 | 0
Current liabilities | 0 | (1)
Pension and other benefit obligations | (105) | (161)
Net amounts recognized at December 31 | (105) | (162)
Amounts recognized in Regulatory Assets consist of: |  |
Net actuarial loss | 180 | 228
Prior service credit | (1) | (1)
Net amount recognized at December 31 | 179 | 227
IPL [Member] | Other Postretirement Benefits Plans [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Non-current assets | 10 | 4
Current liabilities | (2) | (2)
Pension and other benefit obligations | (18) | (19)
Net amounts recognized at December 31 | (10) | (17)
Amounts recognized in Regulatory Assets consist of: |  |
Net actuarial loss | 13 | 20
Prior service credit | 0 | 0
Net amount recognized at December 31 | 13 | 20
WPL [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Pension and other benefit obligations | (159) | (222)
WPL [Member] | Pension Plans, Defined Benefit [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Non-current assets | 0 | 0
Current liabilities | 0 | 0
Pension and other benefit obligations | (96) | (152)
Net amounts recognized at December 31 | (96) | (152)
Amounts recognized in Regulatory Assets consist of: |  |
Net actuarial loss | 188 | 233
Prior service credit | (1) | (1)
Net amount recognized at December 31 | 187 | 232
WPL [Member] | Other Postretirement Benefits Plans [Member] |  |
Amounts recognized on the balance sheets consist of: |  |
Non-current assets | 3 | 3
Current liabilities | (6) | (6)
Pension and other benefit obligations | (61) | (68)
Net amounts recognized at December 31 | (64) | (71)
Amounts recognized in Regulatory Assets consist of: |  |
Net actuarial loss | 18 | 25
Prior service credit | (1) | (1)
Net amount recognized at December 31 | $ 17 | $ 24

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