Earnings or Loss per Share (Net Earnings (Loss) From Continuing Operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings (loss) from continuing operations	$ 315.6	$ (985.6)	$ 12,889.2	$ (502.2)
Net earnings from continuing operations attributable to noncontrolling interests	(41.6)	(49.5)	(142.8)	(137.8)
Net earnings (loss) attributable to Liberty Global shareholders	$ 274.0	$ (1,035.1)	$ 12,746.4	$ (640.0)