Share-based Compensation (Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 58.0	$ 104.4	$ 220.6	$ 243.4
Other operating expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	1.6	2.5	10.4	4.8
SG&A expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	56.4	101.9	210.2	238.6
Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	51.1	91.7	188.7	219.3
Performance-based incentive awards | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	11.9	57.0	50.3	106.3
Non-performance based incentive awards (b) | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	31.4	27.8	116.2	93.9
Other (d)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	6.9	12.7	31.9	24.1
Other (d) | Liberty Global
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 7.8	$ 6.9	$ 22.2	$ 19.1