v3.10.0.1
Long-lived Assets (Schedule of PP&E) (Details) - USD ($)
$ in Millions
Jun. 30, 2018
Dec. 31, 2017
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross $ 27,393.2 $ 26,747.4
Accumulated depreciation (13,340.2) (12,502.1)
Total property and equipment, net 14,053.0 14,245.3
Distribution systems    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross 17,714.5 17,522.9
Customer premises equipment    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross 4,633.9 4,434.3
Support equipment, buildings and land    
Property, Plant and Equipment [Line Items]    
Total property and equipment, gross $ 5,044.8 $ 4,790.2