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Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Deferred tax liabilities, property | $ 2,389 | $ 2,232
Deferred tax liabilities, other | 111 | 101
Total deferred tax liabilities | 2,623 | 2,449
Deferred tax assets, federal credit carryforwards | 560 | 454
Deferred tax assets, net operating losses carryforwards - federal | 39 | 77
Deferred tax assets, net operating losses carryforwards - state | 38 | 37
Deferred tax assets, other | 65 | 73
Subtotal deferred tax assets | 702 | 641
Deferred tax assets, valuation allowances | (6) | (6)
Total deferred tax assets | 696 | 635
Total deferred tax liabilities, net | 1,927 | 1,814
IPL [Member] |  |
Deferred tax liabilities, property | 1,416 | 1,312
Deferred tax liabilities, other | 76 | 83
Total deferred tax liabilities | 1,492 | 1,395
Deferred tax assets, federal credit carryforwards | 345 | 258
Deferred tax assets, net operating losses carryforwards - federal | 36 | 71
Deferred tax assets, net operating losses carryforwards - state | 3 | 1
Deferred tax assets, other | 25 | 30
Subtotal deferred tax assets | 409 | 360
Deferred tax assets, valuation allowances | 0 | 0
Total deferred tax assets | 409 | 360
Total deferred tax liabilities, net | 1,083 | 1,035
WPL [Member] |  |
Deferred tax liabilities, property | 913 | 854
Deferred tax liabilities, other | 50 | 41
Total deferred tax liabilities | 963 | 895
Deferred tax assets, federal credit carryforwards | 192 | 175
Deferred tax assets, net operating losses carryforwards - federal | 0 | 1
Deferred tax assets, net operating losses carryforwards - state | 0 | 0
Deferred tax assets, other | 18 | 18
Subtotal deferred tax assets | 210 | 194
Deferred tax assets, valuation allowances | 0 | (1)
Total deferred tax assets | 210 | 193
Total deferred tax liabilities, net | 753 | 702
ATC Holdings [Member] |  |
Deferred tax liabilities, ATC Holdings | $ 123 | $ 116

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