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Benefit Plans (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Benefit Plans [Line Items] |  |
Total plan assets (less than 1%), percentage of common stock | 1.00% | 1.00%
Common stock percentage in assets held in 401(k) saving plans | 9.00% | 9.00%
Unrecognized compensation cost | $ 5 |
Percentage of base salary and short-term cash incentive compensation | 100.00% |
Carrying value of deferred compensation obligations | $ 22 | $ 22
Performance Shares Equity Awards [Member] |  |
Benefit Plans [Line Items] |  |
Performance period | 3 years |
Performance Shares and Performance Units Liability Awards [Member] |  |
Benefit Plans [Line Items] |  |
Performance period | 3 years |
Instrument valuation based on shares of common stock, number of shares | 1 |
Restricted Stock Units Equity Awards [Member] |  |
Benefit Plans [Line Items] |  |
Performance period | 3 years |
Instrument valuation based on shares of common stock, number of shares | 1 |
Restricted Stock Units Liability Awards [Member] |  |
Benefit Plans [Line Items] |  |
Performance period | 3 years |
Instrument valuation based on shares of common stock, number of shares | 1 |
Performance Restricted Stock Units Equity Awards [Member] |  |
Benefit Plans [Line Items] |  |
Performance period | 3 years |
Instrument valuation based on shares of common stock, number of shares | 1 |
Minimum [Member] |  |
Benefit Plans [Line Items] |  |
Unrecognized compensation cost recognized over a weighted average period | 1 year |
Minimum [Member] | Performance Shares Equity Awards [Member] |  |
Benefit Plans [Line Items] |  |
Actual number of shares paid out upon vesting, percentage of target shares | 0.00% |
Minimum [Member] | Performance Shares and Performance Units Liability Awards [Member] |  |
Benefit Plans [Line Items] |  |
Actual number of shares paid out upon vesting, percentage of target shares | 0.00% |
Minimum [Member] | Performance Restricted Stock Units Equity Awards [Member] |  |
Benefit Plans [Line Items] |  |
Actual number of shares paid out upon vesting, percentage of target shares | 0.00% |
Maximum [Member] |  |
Benefit Plans [Line Items] |  |
Unrecognized compensation cost recognized over a weighted average period | 2 years |
Maximum [Member] | Performance Shares Equity Awards [Member] |  |
Benefit Plans [Line Items] |  |
Actual number of shares paid out upon vesting, percentage of target shares | 200.00% |
Maximum [Member] | Performance Shares and Performance Units Liability Awards [Member] |  |
Benefit Plans [Line Items] |  |
Actual number of shares paid out upon vesting, percentage of target shares | 200.00% |
Maximum [Member] | Performance Restricted Stock Units Equity Awards [Member] |  |
Benefit Plans [Line Items] |  |
Actual number of shares paid out upon vesting, percentage of target shares | 200.00% |
IPL [Member] |  |
Benefit Plans [Line Items] |  |
Unrecognized compensation cost | $ 3 |
WPL [Member] |  |
Benefit Plans [Line Items] |  |
Unrecognized compensation cost | 2 |
Other Postretirement Benefits Plans [Member] |  |
Benefit Plans [Line Items] |  |
Plan asset threshold for long-term allocation targets | 5 |
Other Postretirement Benefits Plans [Member] | IPL [Member] |  |
Benefit Plans [Line Items] |  |
Plan asset threshold for long-term allocation targets | 5 |
Other Postretirement Benefits Plans [Member] | WPL [Member] |  |
Benefit Plans [Line Items] |  |
Plan asset threshold for long-term allocation targets | $ 5 |
Omnibus Incentive Plan [Member] |  |
Benefit Plans [Line Items] |  |
Shares available for issuance under the Amended and Restated OIP (in shares) | 9,000,000 |
Shares included in diluted earnings per share (in shares) | 653,956 |

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- Definition Common stock percentage in assets held saving plans. + References No definition available. + Details
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- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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