Acquisitions and Dispositions (Narrative) (Details) € in Millions, SFr in Millions								3 Months Ended			9 Months Ended
	Jul. 31, 2019 EUR (€)	Jul. 31, 2019 USD ($)	Jun. 03, 2019 EUR (€)	Jun. 03, 2019 USD ($)	May 02, 2019 EUR (€)	May 02, 2019 USD ($)	Jul. 31, 2018	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jun. 02, 2019	Feb. 27, 2019 CHF (SFr)	Feb. 27, 2019 USD ($)	Dec. 31, 2018 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds received upon disposition of discontinued operations, net											$ 11,219,900,000	$ 2,061,200,000
Carrying value								$ 26,890,100,000			26,890,100,000					$ 29,183,900,000
Funding of the Vodafone Escrow Accounts, net											(306,500,000)	0
Gain on disposal of discontinued operations, net of taxes								12,205,700,000		$ 1,098,100,000	12,312,300,000	$ 1,098,100,000
Vodafone Disposal Group | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash to be paid to settle obligations	€ 183.7	$ 205,800,000
Proceeds received upon disposition of discontinued operations, net	€ 10,000.0	11,100,000,000
Gain on disposal of discontinued operations, net of taxes		12,200,000,000
Cumulative foreign currency translation gain (loss)		88,200,000
Income tax on gain		$ 11,700,000
Term of transitional services	4 years	4 years
Revenue from transitional services								25,500,000
UPC Switzerland
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Carrying value								$ 1,645,000,000.0			1,645,000,000.0
UPC Austria | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Term of transitional services							4 years
Revenue from transitional services											34,300,000
UPC DTH | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds received upon disposition of discontinued operations, net					€ 130.5	$ 145,800,000
Gain on disposal of discontinued operations, net of taxes						106,600,000
Cumulative foreign currency translation gain (loss)						(10,000,000.0)
Income tax on gain						$ 0
Term of transitional services					2 years	2 years
Revenue from transitional services											$ 900,000
Sunrise Communications Group AG
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Termination fee															$ 50,100,000
Sunrise Communications Group AG | UPC Switzerland
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Termination fee | SFr														SFr 50.0
De Vijver Media
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Previous interest													50.00%
Interest acquired			50.00%	50.00%
Consideration transferred			€ 52.5	$ 58,900,000
Repayment of debt			€ 62.0	$ 69,500,000
Gain on remeasurement									$ 25,700,000
Fair value									$ 57,900,000