Dispositions and the VodafoneZiggo JV Transaction (Pending and Completed Dispositions) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating results of discontinued operations
Revenue	$ 2,982.2	$ 2,840.9	$ 2,850.4	$ 2,868.0	$ 2,949.1	$ 2,929.7	$ 3,015.6	$ 3,063.5	$ 11,541.5	$ 11,957.9	$ 11,276.4
Earnings (loss) before income taxes									(1,156.0)	161.8	(2,111.1)
Net earnings (loss)									$ 13,047.2	$ 2,261.5	$ (370.6)
Weighted average ordinary shares outstanding (LiLAC Shares) - basic and diluted (in shares)									705,794,546	778,675,957	847,894,601
Discontinued Operations
Operating results of discontinued operations
Revenue										$ 3,953.6	$ 7,362.5
Operating income (loss)										1,937.7	974.8
Earnings (loss) before income taxes										1,544.6	(96.0)
Income tax benefit (expense)										(381.2)	(274.6)
Net earnings (loss)										1,163.4	(370.6)
Net loss (earnings) attributable to noncontrolling interests										(4.2)	13.8
Net earnings (loss) attributable to Liberty Global shareholders										$ 1,159.2	$ (356.8)
Basic and diluted earnings (loss) from discontinued operations attributable to Liberty Global shareholders (in dollars per share)									$ 1.03	$ 1.49	$ 0.56
Weighted average ordinary shares outstanding (LiLAC Shares) - basic and diluted (in shares)											171,846,133
Discontinued Operations, Disposed of by Sale
Assets:
Current assets other than cash					356.5					$ 356.5
Property and equipment, net					5,671.1					5,671.1
Goodwill					3,986.7					3,986.7
Other assets, net					516.8					516.8
Total assets					10,531.1					10,531.1
Liabilities:
Current portion of debt and finance lease obligations					820.2					820.2
Other accrued and current liabilities					1,147.3					1,147.3
Long-term debt and finance lease obligations					9,074.6					9,074.6
Other long-term liabilities					997.8					997.8
Total liabilities					12,039.9					12,039.9
Discontinued Operations, Split-off Transaction
Operating results of discontinued operations
Revenue									$ 2,054.6
Operating income (loss)									1,176.3
Earnings (loss) before income taxes									1,004.2
Income tax benefit (expense)									(273.9)
Net earnings (loss) attributable to Liberty Global shareholders									730.3
UPC Austria | Discontinued Operations, Split-off Transaction
Operating results of discontinued operations
Revenue										252.4	$ 394.9
Operating income (loss)										139.0	150.0
Earnings (loss) before income taxes										138.7	150.0
Income tax benefit (expense)										(23.3)	(4.5)
Net earnings (loss)										115.4	145.5
Net loss (earnings) attributable to noncontrolling interests										(4.2)	(6.8)
Net earnings (loss) attributable to Liberty Global shareholders										111.2	138.7
Vodafone Disposal Group | Discontinued Operations, Disposed of by Sale
Assets:
Current assets other than cash					348.0					348.0
Property and equipment, net					5,591.4					5,591.4
Goodwill					3,986.7					3,986.7
Other assets, net					509.4					509.4
Total assets					10,435.5					10,435.5
Liabilities:
Current portion of debt and finance lease obligations					809.0					809.0
Other accrued and current liabilities					1,114.8					1,114.8
Long-term debt and finance lease obligations					9,037.1					9,037.1
Other long-term liabilities					997.5					997.5
Total liabilities					11,958.4					11,958.4
Vodafone Disposal Group | Discontinued Operations, Split-off Transaction
Operating results of discontinued operations
Revenue									2,017.9	3,584.2	3,263.0
Operating income (loss)									1,165.6	1,787.0	976.0
Earnings (loss) before income taxes									994.7	1,396.3	395.4
Income tax benefit (expense)									(273.9)	(365.2)	(66.1)
Net earnings (loss)										1,031.1	329.3
Net loss (earnings) attributable to noncontrolling interests										0.0	0.0
Net earnings (loss) attributable to Liberty Global shareholders									720.8	1,031.1	329.3
UPC DTH | Discontinued Operations, Disposed of by Sale
Assets:
Current assets other than cash					8.5					8.5
Property and equipment, net					79.7					79.7
Goodwill					0.0					0.0
Other assets, net					7.4					7.4
Total assets					95.6					95.6
Liabilities:
Current portion of debt and finance lease obligations					11.2					11.2
Other accrued and current liabilities					32.5					32.5
Long-term debt and finance lease obligations					37.5					37.5
Other long-term liabilities					0.3					0.3
Total liabilities					$ 81.5					81.5
UPC DTH | Discontinued Operations, Split-off Transaction
Operating results of discontinued operations
Revenue									36.7	117.0	114.6
Operating income (loss)									10.7	11.7	11.7
Earnings (loss) before income taxes									9.5	9.6	9.7
Income tax benefit (expense)									0.0	7.3	0.0
Net earnings (loss)										16.9	9.7
Net loss (earnings) attributable to noncontrolling interests										0.0	0.0
Net earnings (loss) attributable to Liberty Global shareholders									$ 9.5	$ 16.9	$ 9.7
LiLAC Shares | Discontinued Operations
Operating results of discontinued operations
Basic and diluted earnings (loss) from discontinued operations attributable to Liberty Global shareholders (in dollars per share)											$ (4.86)
LiLAC Shares | Discontinued Operations, Split-off Transaction
Operating results of discontinued operations
Revenue											$ 3,590.0
Operating income (loss)											(162.9)
Earnings (loss) before income taxes											(651.1)
Income tax benefit (expense)											(204.0)
Net earnings (loss)											(855.1)
Net loss (earnings) attributable to noncontrolling interests											20.6
Net earnings (loss) attributable to Liberty Global shareholders											$ (834.5)