Investments (Schedule of Investments by Accounting Method) (Details) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Investment [Line Items]
Fair value	$ 4,364.3	$ 3,481.8
Equity	165.0	8.9
Cost	0.4	0.5
Total	4,529.7	3,491.2
Ziggo N.V. [Member]
Investment [Line Items]
Fair value	2,670.0	2,609.5
Number of common stock shares owned (in shares)	57,000,738
Ziggo N.V. [Member] | Securities Not Subject to Re-Use Rights [Member]
Investment [Line Items]
Fair value	1,825.4	1,560.1
Number of common stock shares owned (in shares)	39,000,000	34,100,000
Ziggo N.V. [Member] | Securities Subject to Re-Use Rights [Member]
Investment [Line Items]
Fair value	844.6	1,049.4
Number of common stock shares owned (in shares)	18,000,000	22,900,000
ITV - Subject to Re-Use Rights [Member]
Investment [Line Items]
Fair value	875.7	0
Sumitomo [Member]
Investment [Line Items]
Fair value	503.9	572.9
Number of common stock shares owned (in shares)	45,652,043
Cyfra, Privately Held DTH Operator in Poland [Member]
Investment [Line Items]
Fair value	$ 314.7	$ 299.4