Basis of Presentation (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2016
Telenet
Basis of Presentation [Line Items]
Percentage ownership in subsidiary	60.20%
VodafoneZiggo JV
Basis of Presentation [Line Items]
Ownership percentage	50.00%	50.00%	50.00%
Co-venturer ownership percentage	50.00%		50.00%
Liberty Puerto Rico
Basis of Presentation [Line Items]
Ownership percentage	60.00%