Share-based Compensation (Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 74.0	$ 42.8	$ 228.3	$ 131.0
Other operating expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	1.1	1.2	3.0	2.2
SG&A expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	72.9	41.6	225.3	128.8
Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	68.5	36.5	209.9	120.0
Performance-based incentive awards | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	28.9	9.3	96.8	26.0
Non-performance based incentive awards | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	31.6	18.3	82.6	64.6
Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	5.5	6.3	18.4	11.0
Other | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 8.0	$ 8.9	$ 30.5	$ 29.4