Leases, Codification Topic 842 (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Lessee, Operating Lease, Contingent Liability		$ 6.8
Operating Lease, Cost		6.3	$ 6.4	$ 6.0
Operating Leased Assets [Line Items]
Cash Paid on Operating Leases		6.3	6.4	5.6
Operating Lease, Right-of-Use Asset	[1]	33.0	37.6
Operating Lease, Liability	[2]	$ 37.6	$ 42.3
Operating Lease, Weighted Average Remaining Lease Term		12 years 2 months 12 days	12 years 6 months
Operating Lease, Weighted Average Discount Rate, Percent		3.90%	3.90%
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		$ 0.0	$ 1.4	10.7
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months		5.7
Lessee, Operating Lease, Liability, Payments, Due Year Two		5.1
Lessee, Operating Lease, Liability, Payments, Due Year Three		3.1
Lessee, Operating Lease, Liability, Payments, Due Year Four		3.0
Lessee, Operating Lease, Liability, Payments, Due Year Five		3.0
Lessee, Operating Lease, Liability, Payments, Due after Year Five		28.7
Lessee, Operating Lease, Liability, Payments, Due		48.6
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		11.0
Lessee, Operating Lease, Contingent Liability		6.8
Operating Lease, Cost		6.3	6.4	6.0
Og and E [Member]
Leases [Abstract]
Operating Lease, Cost		5.7	5.5	5.1
Operating Leased Assets [Line Items]
Cash Paid on Operating Leases		5.7	5.5	4.8
Operating Lease, Right-of-Use Asset	[1]	33.0	37.0
Operating Lease, Liability	[2]	$ 37.6	$ 41.7
Operating Lease, Weighted Average Remaining Lease Term		12 years 2 months 12 days	12 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent		3.90%	3.90%
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		$ 0.0	$ 1.4	10.7
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months		5.7
Lessee, Operating Lease, Liability, Payments, Due Year Two		5.1
Lessee, Operating Lease, Liability, Payments, Due Year Three		3.1
Lessee, Operating Lease, Liability, Payments, Due Year Four		3.0
Lessee, Operating Lease, Liability, Payments, Due Year Five		3.0
Lessee, Operating Lease, Liability, Payments, Due after Year Five		28.7
Lessee, Operating Lease, Liability, Payments, Due		48.6
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		11.0
Operating Lease, Cost		$ 5.7	$ 5.5	$ 5.1

[1] Included in Property, Plant and Equipment in the Registrants' balance sheets.

[2] Included in Other Deferred Credits and Other Liabilities in the Registrants' balance sheets.