Investments (Schedule of Investments by Accounting Method) (Details) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Investment [Line Items]
Fair value	$ 3,573.3	$ 3,481.8
Equity	19.3	8.9
Cost	0.5	0.5
Total	3,593.1	3,491.2
Ziggo N.V. [Member]
Investment [Line Items]
Fair value	2,635.3	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	1,791.2	1,560.1
Number of common stock shares owned (in shares)	38,700,000	34,100,000
Ziggo N.V. [Member] | Securities Subject to Re-Use Rights [Member]
Investment [Line Items]
Fair value	844.1	1,049.4
Number of common stock shares owned (in shares)	18,300,000	22,900,000
Sumitomo [Member]
Investment [Line Items]
Fair value	616.6	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	$ 321.4	$ 299.4