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- Definition

The date amortization of a regulatory asset or liability begins.

+ References

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- Definition

Multi-Year Rate Plan Reconciliation Cap

+ References

No definition available.

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- Definition

Ameren Illinois' requested multi-year rate plan revenue requirement.

+ References

No definition available.

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- Definition

Number of Performance Metrics

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No definition available.

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- Definition

Rate And Regulatory Matters [Line Items]

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No definition available.

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- Definition

Value established for a utility on which the entity is allowed to earn a particular rate of return

+ References

No definition available.

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- Definition

The return on equity adjustments related to the achievement of certain performance metrics requested by Ameren Illinois.

+ References

No definition available.

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- Definition

Percentage of public utility's approved equity to capital, including debt and equity.

+ References

No definition available.

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- Definition

Percentage of public utility's requested equity to capital, including debt and equity.

+ References

No definition available.

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- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

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- Definition

Percentage of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

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- Definition

Percentage of public utility's requested return on equity.

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Rate And Regulatory Matters (Narrative-Illinois) (Details) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($) numberOfProposedPerformanceMetrics	Mar. 31, 2022 USD ($)	Dec. 31, 2027 USD ($)	Dec. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Rate And Regulatory Matters [Line Items]
Revenues		$ 2,062	$ 1,879
Ameren Illinois Company
Rate And Regulatory Matters [Line Items]
Revenues		$ 1,101	$ 1,024
Ameren Illinois Company \| Electric Distribution
Rate And Regulatory Matters [Line Items]
Number of Performance Metrics \| numberOfProposedPerformanceMetrics		7
Requested Return on Equity Adjustment		0.24%
IETL \| Ameren Illinois Company \| Electric Distribution
Rate And Regulatory Matters [Line Items]
Public Utilities, Approved Equity Capital Structure, Percentage		50.00%
Amortization Period		2 years
Amortization Start Date		1 year
Multi-Year Rate Plan Reconciliation Cap		105.00%
IETL \| Ameren Illinois Company \| Electric Distribution \| Subsequent Event
Rate And Regulatory Matters [Line Items]
Multi-year rate plan requested revenue requirement				$ 1,556	$ 1,477	$ 1,373	$ 1,282
Public Utilities, Requested Return on Equity, Percentage				10.50%	10.50%	10.50%	10.50%
Public Utilities, Requested Equity Capital Structure, Percentage				54.03%	54.02%	53.97%	53.99%
Rate Base				$ 5,300	$ 5,000	$ 4,600	$ 4,300
Public Utilities, Requested Rate Increase (Decrease), Percentage							50.00%
Public Utilities, Requested Rate Increase (Decrease), Amount							$ 171
IETL \| Ameren Illinois Company \| Electric Distribution \| Minimum
Rate And Regulatory Matters [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Percentage		50.00%
Pending Rate Case \| Ameren Illinois Company \| Electric Distribution \| Subsequent Event
Rate And Regulatory Matters [Line Items]
Public Utilities, Requested Equity Capital Structure, Percentage	53.99%
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 127
Pending Rate Case \| Ameren Illinois Company \| Natural gas
Rate And Regulatory Matters [Line Items]
Public Utilities, Requested Return on Equity, Percentage		10.70%
Public Utilities, Requested Equity Capital Structure, Percentage		53.99%
Rate Base		$ 2,900
Public Utilities, Requested Rate Increase (Decrease), Amount		160
Revenues		$ 77