Debt and Capital Lease Obligations (Components of Debt and Capital Lease Obligations) (Details) € in Millions	3 Months Ended
	Mar. 31, 2018 GBP (£) group	Mar. 31, 2018 EUR (€) group	Mar. 31, 2018 USD ($) group	Feb. 28, 2018 GBP (£)	Feb. 28, 2018 USD ($)	Jan. 31, 2018 GBP (£)	Jan. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Weighted average interest rate	4.35%	4.35%	4.35%
Unused borrowing capacity			$ 3,624,600,000
Estimated fair value			41,716,300,000					$ 41,859,300,000
Total debt before deferred financing costs, discounts and premiums			41,333,100,000					41,017,600,000
Deferred financing costs, discounts and premiums, net			(216,700,000)					(223,200,000)
Total carrying amount of debt			41,116,400,000					40,794,400,000
Capital lease obligations			1,450,300,000					1,420,500,000
Total debt and capital lease obligations			42,566,700,000					42,214,900,000
Current maturities of debt and capital lease obligations			(4,290,700,000)					(4,165,400,000)
Long-term debt and capital lease obligations			38,276,000,000.0					38,049,500,000
General term of vendor financing arrangements	1 year
Debt			$ 949,600,000					965,700,000
Number of borrowing groups | group	4	4	4
Virgin Media [Member]
Debt Instrument [Line Items]
Deferred financing costs, discounts and premiums, net			$ (61,600,000)
Capital lease obligations			81,300,000					79,100,000
Unitymedia [Member]
Debt Instrument [Line Items]
Deferred financing costs, discounts and premiums, net			(50,700,000)
Capital lease obligations			733,600,000					722,400,000
Telenet [Member]
Debt Instrument [Line Items]
Deferred financing costs, discounts and premiums, net			(24,500,000)
Capital lease obligations			476,200,000					456,100,000
UPC Holding [Member]
Debt Instrument [Line Items]
Deferred financing costs, discounts and premiums, net			(52,400,000)
Capital lease obligations			95,400,000					95,700,000
Other [Member]
Debt Instrument [Line Items]
Deferred financing costs, discounts and premiums, net			(27,500,000)
Capital lease obligations			63,800,000					67,200,000
Significant other observable inputs (Level 2)
Debt Instrument [Line Items]
Debt			$ 334,500,000					344,000,000.0
VM Notes [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.54%	5.54%	5.54%
Unused borrowing capacity	£ 0		$ 0
Estimated fair value			9,891,300,000					9,987,400,000
Total debt before deferred financing costs, discounts and premiums			$ 9,750,900,000					9,565,700,000
VM Credit Facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.19%	4.19%	4.19%
Unused borrowing capacity			$ 946,200,000
Estimated fair value			4,889,000,000.0					4,681,500,000
Total debt before deferred financing costs, discounts and premiums			$ 4,869,200,000					4,676,200,000
Unitymedia Notes [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.73%	4.73%	4.73%
Unused borrowing capacity		€ 0.0	$ 0
Estimated fair value			5,892,300,000					5,773,300,000
Total debt before deferred financing costs, discounts and premiums			$ 5,555,200,000					5,465,200,000
Unitymedia Credit Facilities [Member]
Debt Instrument [Line Items]
Weighted average interest rate	3.55%	3.55%	3.55%
Unused borrowing capacity		€ 500.0	$ 614,600,000
Estimated fair value			2,718,700,000					2,698,400,000
Total debt before deferred financing costs, discounts and premiums			$ 2,719,000,000.0					2,696,800,000
UPCB SPE Notes [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.49%	4.49%	4.49%
Unused borrowing capacity		€ 0.0	$ 0
Estimated fair value			2,580,900,000					2,638,800,000
Total debt before deferred financing costs, discounts and premiums			$ 2,614,900,000					2,582,600,000
UPC Holding Bank Facility [Member]
Debt Instrument [Line Items]
Weighted average interest rate	3.91%	3.91%	3.91%
Unused borrowing capacity		€ 990.1	$ 1,216,900,000
Estimated fair value			2,596,800,000					2,576,400,000
Total debt before deferred financing costs, discounts and premiums			$ 2,589,600,000					2,576,100,000
UPC Holding Senior Notes [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.55%	4.55%	4.55%
Unused borrowing capacity		€ 0.0	$ 0
Estimated fair value			1,242,200,000					1,272,500,000
Total debt before deferred financing costs, discounts and premiums			$ 1,330,500,000					1,313,400,000
Telenet Credit Facility [Member]
Debt Instrument [Line Items]
Weighted average interest rate	3.65%	3.65%	3.65%
Unused borrowing capacity			$ 846,900,000
Estimated fair value			2,211,300,000					2,188,900,000
Total debt before deferred financing costs, discounts and premiums			$ 2,197,200,000					2,177,600,000
Telenet Senior Secured Notes [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.65%	4.65%	4.65%
Unused borrowing capacity		€ 0.0	$ 0
Estimated fair value			1,677,300,000					1,724,400,000
Total debt before deferred financing costs, discounts and premiums			$ 1,737,500,000					1,721,300,000
Telenet SPE Notes [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.52%	5.52%	5.52%
Unused borrowing capacity		€ 0.0	$ 0
Estimated fair value			960,200,000					1,014,400,000
Total debt before deferred financing costs, discounts and premiums			$ 893,600,000					937,700,000
Vendor Financing [Member]
Debt Instrument [Line Items]
Weighted average interest rate	3.74%	3.74%	3.74%
Unused borrowing capacity			$ 0
Estimated fair value			3,768,100,000					4,039,700,000
Total debt before deferred financing costs, discounts and premiums			$ 3,768,100,000					4,039,700,000
ITV Collar Loan [Member]
Debt Instrument [Line Items]
Weighted average interest rate	0.71%	0.71%	0.71%
Unused borrowing capacity			$ 0
Estimated fair value			1,484,600,000					1,445,800,000
Total debt before deferred financing costs, discounts and premiums			$ 1,517,100,000					1,463,800,000
Sumitomo Share Loan [Member]
Debt Instrument [Line Items]
Weighted average interest rate	0.95%	0.95%	0.95%
Unused borrowing capacity		€ 0.0	$ 0
Estimated fair value			615,100,000					621,700,000
Total debt before deferred financing costs, discounts and premiums			$ 615,100,000					621,700,000
Derivative-related debt instruments [Member]
Debt Instrument [Line Items]
Weighted average interest rate	3.38%	3.38%	3.38%
Unused borrowing capacity			$ 0
Estimated fair value			604,400,000					612,400,000
Total debt before deferred financing costs, discounts and premiums			$ 585,600,000					592,500,000
Sumitomo Collar Loan [Member]
Debt Instrument [Line Items]
Weighted average interest rate	1.88%	1.88%	1.88%
Unused borrowing capacity		€ 0.0	$ 0
Estimated fair value			179,400,000					170,300,000
Total debt before deferred financing costs, discounts and premiums			$ 178,900,000					169,100,000
Other [Member]
Debt Instrument [Line Items]
Weighted average interest rate	5.70%	5.70%	5.70%
Unused borrowing capacity			$ 0
Estimated fair value			404,700,000					413,400,000
Total debt before deferred financing costs, discounts and premiums			410,700,000					418,200,000
Other [Member] | Virgin Media [Member]
Debt Instrument [Line Items]
Total carrying amount of debt			$ 158,400,000					$ 160,900,000
Aggregate Variable and Fixed Rate Indebtedness [Member]
Debt Instrument [Line Items]
Weighted average interest rate	4.20%	4.20%	4.20%
VM Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility amount						£ 675,000,000.0	$ 946,200,000
VM Revolving Facility A [Member]
Debt Instrument [Line Items]
Facility amount				£ 75,000,000.0	$ 105,200,000
VM Revolving Facility B [Member]
Debt Instrument [Line Items]
Facility amount				£ 600,000,000.0	$ 841,000,000.0
Telenet Facility AG [Member]
Debt Instrument [Line Items]
Unused borrowing capacity		€ 400.0	$ 491,600,000
Telenet Facility AL Add-on [Member]
Debt Instrument [Line Items]
Unused borrowing capacity			300,000,000.0
Telenet Overdraft Facility [Member]
Debt Instrument [Line Items]
Unused borrowing capacity		25.0	30,700,000
Telenet Revolving Facility [Member]
Debt Instrument [Line Items]
Unused borrowing capacity		€ 20.0	$ 24,600,000