Share-based Compensation (Summary of Stock-Based Compensation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 39.0	$ 69.0
Other operating expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1.4	0.7
SG&A expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	37.6	68.3
Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2.4	1.5
Liberty Global Group [Member] | Other operating expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	0.9	0.5
Liberty Global Group [Member] | SG&A expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	32.5	66.7
LiLAC Group [Member] | Other operating expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	0.5	0.2
LiLAC Group [Member] | SG&A expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	5.1	1.6
Parent Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	32.6	66.5
Parent Company [Member] | Performance-based incentive awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	4.5	41.1
Parent Company [Member] | Other share-based incentive awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	28.1	25.4
Telenet [Member] | Telenet share-based incentive awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4.0	$ 1.0