Commitments and Contingencies (Narrative) (Details) € in Millions, £ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	Dec. 31, 2015 EUR (€)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 GBP (£)	Dec. 31, 2018 EUR (€)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 GBP (£)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 GBP (£)
Loss Contingencies [Line Items]
Programming and copyright costs						$ 1,671,400,000		$ 1,470,200,000	$ 1,783,400,000
Rent expense under non-cancelable operating lease arrangements						111,800,000		104,500,000	125,700,000
Aggregate expense for matching contributions under various defined contribution plans						41,000,000.0		$ 34,700,000	$ 67,600,000
Maximum | Unfavorable Regulatory Action | Scenario, Forecast | U.K.
Loss Contingencies [Line Items]
Estimate of possible loss										$ 36,000,000	£ 28.0
Interkabel Acquisition
Loss Contingencies [Line Items]
Loss contingency damages in excess value					€ 20.0							$ 22,900,000
Damages sought	€ 1,400.0	$ 1,600,000,000
Loss contingency accrual												$ 0
Deutsche Telekom Litigation
Loss Contingencies [Line Items]
Damages sought					€ 75.0	$ 86,000,000
Reduction of annual lease fees					83.33%	83.33%	83.33%
Belgium Regulatory Developments
Loss Contingencies [Line Items]
Percent of Reduction in Monthly Wholesale Cable Resale Access Prices					17.00%							17.00%	17.00%
Virgin Media VAT Matters
Loss Contingencies [Line Items]
Loss contingency accrual												$ 0
Virgin Media VAT Matters | Maximum
Loss Contingencies [Line Items]
Estimate of possible loss					€ 47.0							60,000,000
Virgin Media VAT Matters 2
Loss Contingencies [Line Items]
Estimate of possible loss												$ 83,100,000	£ 63.7
Income tax paid			$ 99,100,000	£ 67.0
Interest expense						$ 4,400,000	£ 3.3