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Business Segment Information (Schedule Of Operating Income Derived From Revenues And Expenses By Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 1,027.4	$ 1,089.5	$ 4,083.4	$ 4,146.0
Consolidated Operating Income (Loss)	233.0	156.7	932.9	900.3
Eliminations
Segment Reporting Information [Line Items]
Revenues	(125.1)	(118.6)	(371.1)	(359.5)
Gas Distribution Operations
Segment Reporting Information [Line Items]
Revenues	531.5	575.5	2,731.8	2,759.6
Consolidated Operating Income (Loss)	52.2	33.4	614.5	624.8
Gas Distribution Operations | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	528.5	572.4	2,722.6	2,750.2
Gas Distribution Operations | Intersegment
Segment Reporting Information [Line Items]
Revenues	3.0	3.1	9.2	9.4
Electric Operations
Segment Reporting Information [Line Items]
Revenues	499.1	516.5	1,360.9	1,384.1
Consolidated Operating Income (Loss)	175.8	123.3	307.3	295.1
Electric Operations | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	498.7	516.3	1,360.2	1,383.5
Electric Operations | Intersegment
Segment Reporting Information [Line Items]
Revenues	0.4	0.2	0.7	0.6
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	121.9	116.1	361.8	361.8
Consolidated Operating Income (Loss)	5.0	0.0	11.1	(19.6)
Corporate and Other | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	0.2	0.8	0.6	12.3
Corporate and Other | Intersegment
Segment Reporting Information [Line Items]
Revenues	$ 121.7	$ 115.3	$ 361.2	$ 349.5

X

- Definition

The net result for the period of deducting operating expenses from operating revenues.

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