Share-based Compensation (Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 104.4	$ 74.0	$ 243.4	$ 228.3
Share-based compensation expense	104.4	74.0	243.4	228.3
Other operating expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	2.5	1.1	4.8	3.0
SG&A expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	101.9	72.9	238.6	225.3
Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	91.7	68.5	219.3	209.9
Performance-based incentive awards | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	57.0	28.9	106.3	96.8
Non-performance based incentive awards | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	27.8	31.6	93.9	82.6
Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	12.7	5.5	24.1	18.4
Other | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 6.9	$ 8.0	$ 19.1	$ 30.5