Investments (Result of Operations) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024
Schedule of Equity Method Investments [Line Items]
Revenue	$ 1,269.1		$ 1,057.9		$ 2,440.3	$ 2,149.2
Earnings (loss) before income taxes	(2,772.9)		352.3		(4,166.2)	1,029.6
Net earnings (loss)	(2,773.8)	$ (1,323.3)	275.2	$ 527.0	(4,097.1)	802.2
VodafoneZiggo JV
Schedule of Equity Method Investments [Line Items]
Revenue	1,123.3		1,091.6		2,175.3	2,205.6
Operating Segments | VodafoneZiggo JV
Schedule of Equity Method Investments [Line Items]
Revenue	1,123.3		1,091.6		2,175.3	2,205.6
VMO2 JV
Schedule of Equity Method Investments [Line Items]
Revenue	3,373.5		3,375.4		6,499.8	6,658.2
Earnings (loss) before income taxes	(403.9)		27.1		(616.1)	70.1
Net earnings (loss)	(308.9)		12.6		(474.7)	35.3
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Revenue	1,123.3		1,091.6		2,175.3	2,205.6
Earnings (loss) before income taxes	(157.6)		(10.0)		(246.6)	(35.5)
Net earnings (loss)	$ (119.9)		$ (15.4)		$ (190.4)	$ (29.0)