SCHEDULE I (Parent Company Information) CONDENSED STATEMENT OF CASH FLOWS (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net earnings (loss)	$ 25.1	$ 974.1	$ 912.6	$ (1,186.5)	$ (992.0)	$ (791.6)	$ (674.3)	$ (320.2)	$ 725.3	$ (2,778.1)	$ 1,705.3
Adjustments to reconcile earnings (loss) from continuing operations to net cash provided by operating activities from continuing operations:
Share-based compensation expense									206.0	162.2	268.1
Depreciation and amortization									3,858.2	3,790.6	4,117.7
Foreign currency transaction losses (gains), net									(90.4)	181.5	326.3
Deferred income tax benefit									438.1	46.6	(1,428.4)
Changes in operating assets and liabilities:
Receivables and other operating assets									635.4	470.6	362.8
Payables and accruals									459.4	(651.7)	(915.1)
Net cash provided by operating activities									5,963.1	5,708.0	5,940.9
Cash flows from investing activities:
Other investing activities, net									131.4	123.0	76.2
Net cash provided (used) by investing activities									87.3	(560.8)	(7,043.4)
Cash flows from financing activities:
Repurchase of Liberty Global ordinary shares									(2,009.9)	(2,976.2)	(1,968.3)
Other financing activities, net									(7.3)	33.9	(8.3)
Net cash provided (used) by financing activities									(6,189.8)	(4,679.6)	1,699.0
Effect of exchange rate changes on cash									(45.1)	115.3	(38.4)
Total									(184.5)	582.9	558.1
Cash and cash equivalents and restricted cash:
Beginning of year				1,682.8				1,087.4	1,682.8	1,087.4	835.5
End of year	1,498.3				1,682.8				1,498.3	1,682.8	1,087.4
Details of end of period cash and cash equivalents and restricted cash:
Cash and cash equivalents												$ 1,480.5	$ 1,672.4	$ 1,076.6
Restricted cash included in other current assets and other assets, net												15.9	8.3	10.8
Total cash and cash equivalents and restricted cash	1,498.3			1,682.8	1,682.8			1,087.4	1,498.3	1,682.8	835.5	1,498.3	1,682.8	1,087.4
Liberty Global Plc
Cash flows from operating activities:
Net earnings (loss)									725.3	(2,778.1)	1,705.3
Adjustments to reconcile earnings (loss) from continuing operations to net cash provided by operating activities from continuing operations:
Equity in losses (earnings) of consolidated subsidiaries, net									(887.9)	2,386.0	(1,279.7)
Share-based compensation expense									20.6	19.8	29.0
Related-party fees and allocations									8.0	55.2	66.3
Depreciation and amortization									1.5	1.0	0.8
Other operating expenses									0.0	0.0	0.7
Foreign currency transaction losses (gains), net									(381.0)	644.8	(45.8)
Deferred income tax benefit									(2.8)	(1.6)	(1.7)
Changes in operating assets and liabilities:
Receivables and other operating assets									(134.8)	502.7	116.4
Payables and accruals									564.4	(160.9)	29.0
Net cash provided by operating activities									(86.7)	668.9	620.3
Cash flows from investing activities:
Distribution and repayments from (investments in and advances to) consolidated subsidiaries, net									(93.4)	1,188.7	(133.6)
Other investing activities, net									0.0	(7.0)	0.3
Net cash provided (used) by investing activities									(93.4)	1,181.7	(133.3)
Cash flows from financing activities:
Borrowings of related-party debt									3,133.3	4,632.7	5,249.8
Repayments of related-party debt									(1,010.0)	(3,496.0)	(3,751.5)
Repurchase of Liberty Global ordinary shares									(2,009.9)	(2,976.2)	(1,968.3)
Proceeds from issuance of Liberty Global shares upon exercise of options									5.7	11.7	17.4
Proceeds associated with call option contracts, net									0.0	0.0	9.2
Other financing activities, net									(1.4)	(8.1)	(9.4)
Net cash provided (used) by financing activities									117.7	(1,835.9)	(452.8)
Effect of exchange rate changes on cash									0.0	(0.4)	(0.3)
Total									(62.4)	14.3	33.9
Cash and cash equivalents and restricted cash:
Beginning of year				78.4				64.1	78.4	64.1	30.2
End of year	16.0				78.4				16.0	78.4	64.1
Details of end of period cash and cash equivalents and restricted cash:
Cash and cash equivalents												10.8	73.2	58.9
Restricted cash included in other current assets and other assets, net												5.2	5.2	5.2
Total cash and cash equivalents and restricted cash	$ 16.0			$ 78.4	$ 78.4			$ 64.1	$ 16.0	$ 78.4	$ 30.2	$ 16.0	$ 78.4	$ 64.1