Derivative Instruments (Realized and Unrealized Gains (Losses) on Derivatives) (Schedule and Footnotes) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative [Line Items]
Gain (loss) on derivative instruments, net	$ (679.7)	$ (328.6)	$ (61.2)	$ (705.2)
Cross-currency and interest rate derivative contracts
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(548.3)	(285.7)	192.2	(705.9)
Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(16.3)	0.4	(24.4)	20.4
Liberty Global Group [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(680.9)	(330.4)	(141.8)	(580.4)
Liberty Global Group [Member] | Cross-currency and interest rate derivative contracts
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(547.7)	(287.6)	114.6	(580.3)
Liberty Global Group [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(18.1)	0.5	(27.4)	19.6
Liberty Global Group [Member] | Equity Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(114.8)	(44.4)	(229.7)	(20.3)
Liberty Global Group [Member] | Other
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(0.3)	1.1	0.7	0.6
Liberty Global Group [Member] | ITV Collar [Member] | Equity Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(53.5)	0.0	(158.9)	0.0
Liberty Global Group [Member] | Sumitomo Collar [Member] | Equity Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(61.8)	(23.8)	(71.9)	(15.3)
Liberty Global Group [Member] | Ziggo Collar [Member] | Equity Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	0.0	(21.3)	0.0	(5.9)
Liberty Global Group [Member] | Other [Member] | Equity Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	0.5	0.7	1.1	0.9
LiLAC Group [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	1.2	1.8	80.6	(124.8)
LiLAC Group [Member] | Cross-currency and interest rate derivative contracts
Derivative [Line Items]
Gain (loss) on derivative instruments, net	(0.6)	1.9	77.6	(125.6)
LiLAC Group [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain (loss) on derivative instruments, net	$ 1.8	$ (0.1)	$ 3.0	$ 0.8