Income Taxes (Narrative) (Details) (USD $)	12 Months Ended								3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Continuing operations [Member]	Dec. 31, 2012 Continuing operations [Member]	Dec. 31, 2011 Continuing operations [Member]	Dec. 31, 2013 Domestic Tax Authority [Member]	Dec. 31, 2013 Foreign Tax Authority [Member]	Mar. 31, 2013 U.K. Tax Expected April 2014 [Member]	Mar. 31, 2013 U.K. Tax Expected April 2015 [Member]	Dec. 31, 2013 Virgin Media [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Statutory income tax rate							23.00%	35.00%	21.00%	20.00%
Change in valuation allowances	$ 4,868,400,000
Change in valuation allowances related to net tax expense	80,900,000	122,700,000	271,000,000	80,900,000
Net operating losses from deductions of stock based compensation excluded from recorded deferred tax assets	74,100,000
Deferred tax liability, temporary difference	8,000,000,000
Unrecognized tax benefits - favorable impact on effective income tax rate if ultimately recognized, net of valuation allowances	419,000,000
Amount on which future tax deductions can be claimed											22,200,000,000
Maximum percent of capital allowances claimed allowance											18.00%
Benefit (expense) from release (accrual) of interest and penalties				(14,000,000)	(7,700,000)	(16,000,000)
Accrued interest and penalties on tax related items	$ 40,800,000