Fair Value Measurements (Assets and Liabilities Reconciliation) (Schedule and Footnote) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of net assets at January 1, 2014	$ 612.9
Partial settlement of the Ziggo Collar (a)	17.9
Gains (losses) included in net loss (b):
Realized and unrealized losses on derivative instruments, net	(124.3)
Realized and unrealized gains due to changes in fair values of certain investments, net	29.5
Foreign currency translation adjustments and other, net	11.1
Balance of net assets at September 30, 2014	547.1
Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of net assets at January 1, 2014	299.4
Partial settlement of the Ziggo Collar (a)	0
Gains (losses) included in net loss (b):
Realized and unrealized losses on derivative instruments, net	0
Realized and unrealized gains due to changes in fair values of certain investments, net	29.5
Foreign currency translation adjustments and other, net	(14.2)
Balance of net assets at September 30, 2014	314.7
Equity-related derivative instruments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of net assets at January 1, 2014	313.5
Partial settlement of the Ziggo Collar (a)	17.9
Gains (losses) included in net loss (b):
Realized and unrealized losses on derivative instruments, net	(124.3)
Realized and unrealized gains due to changes in fair values of certain investments, net	0
Foreign currency translation adjustments and other, net	25.3
Balance of net assets at September 30, 2014	$ 232.4