Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 1,083	$ 1,028
Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	595	582
Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	341	347
Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	61	53
Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	40	17
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	46	29
IPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	561	546
IPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	276	286
IPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	201	205
IPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	31	29
IPL [Member] | Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	27	12
IPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	26	14
WPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	522	482
WPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	319	296
WPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	140	142
WPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	30	24
WPL [Member] | Commodity cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	13	5
WPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 20	$ 15