Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	Dec. 31, 2020 USD ($)
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	$ 383
Minimum future commitments, 2022	218
Minimum future commitments, 2023	165
Minimum future commitments, 2024	113
Minimum future commitments, 2025	71
Minimum future commitments, Thereafter	214
Minimum future commitments, Total	1,164
Individual commitments incurred	1
Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	252
Minimum future commitments, 2022	174
Minimum future commitments, 2023	137
Minimum future commitments, 2024	105
Minimum future commitments, 2025	68
Minimum future commitments, Thereafter	185
Minimum future commitments, Total	921
Coal [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	70
Minimum future commitments, 2022	27
Minimum future commitments, 2023	17
Minimum future commitments, 2024	0
Minimum future commitments, 2025	0
Minimum future commitments, Thereafter	0
Minimum future commitments, Total	114
Other [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	61
Minimum future commitments, 2022	17
Minimum future commitments, 2023	11
Minimum future commitments, 2024	8
Minimum future commitments, 2025	3
Minimum future commitments, Thereafter	29
Minimum future commitments, Total	129
IPL [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	187
Minimum future commitments, 2022	109
Minimum future commitments, 2023	96
Minimum future commitments, 2024	70
Minimum future commitments, 2025	40
Minimum future commitments, Thereafter	98
Minimum future commitments, Total	600
IPL [Member] \| Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	130
Minimum future commitments, 2022	88
Minimum future commitments, 2023	79
Minimum future commitments, 2024	68
Minimum future commitments, 2025	38
Minimum future commitments, Thereafter	71
Minimum future commitments, Total	474
IPL [Member] \| Coal [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	32
Minimum future commitments, 2022	16
Minimum future commitments, 2023	13
Minimum future commitments, 2024	0
Minimum future commitments, 2025	0
Minimum future commitments, Thereafter	0
Minimum future commitments, Total	61
IPL [Member] \| Other [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	25
Minimum future commitments, 2022	5
Minimum future commitments, 2023	4
Minimum future commitments, 2024	2
Minimum future commitments, 2025	2
Minimum future commitments, Thereafter	27
Minimum future commitments, Total	65
WPL [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	186
Minimum future commitments, 2022	99
Minimum future commitments, 2023	63
Minimum future commitments, 2024	38
Minimum future commitments, 2025	31
Minimum future commitments, Thereafter	115
Minimum future commitments, Total	532
WPL [Member] \| Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	122
Minimum future commitments, 2022	86
Minimum future commitments, 2023	58
Minimum future commitments, 2024	37
Minimum future commitments, 2025	30
Minimum future commitments, Thereafter	114
Minimum future commitments, Total	447
WPL [Member] \| Coal [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	38
Minimum future commitments, 2022	11
Minimum future commitments, 2023	4
Minimum future commitments, 2024	0
Minimum future commitments, 2025	0
Minimum future commitments, Thereafter	0
Minimum future commitments, Total	53
WPL [Member] \| Other [Member]
Long-term Purchase Commitment [Line Items]
Minimum future commitments, 2021	26
Minimum future commitments, 2022	2
Minimum future commitments, 2023	1
Minimum future commitments, 2024	1
Minimum future commitments, 2025	1
Minimum future commitments, Thereafter	1
Minimum future commitments, Total	$ 32

Individual commitments incurred in excess of $1 million

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Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

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Amount of purchase arrangement to be paid in second fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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