Long-lived Assets (Schedule of PP&E) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment gross	$ 14,929.6	$ 14,539.6
Accumulated depreciation	(8,252.7)	(8,035.1)
Total property and equipment, net	6,676.9	6,504.5
Distribution systems
Property, Plant and Equipment [Line Items]
Property and equipment gross	9,428.5	9,134.3
Support equipment, buildings and land
Property, Plant and Equipment [Line Items]
Property and equipment gross	4,196.5	4,067.2
Customer premises equipment
Property, Plant and Equipment [Line Items]
Property and equipment gross	$ 1,304.6	$ 1,338.1