Investments - Narrative (Details) - USD ($)					3 Months Ended									12 Months Ended
	Jan. 22, 2019	May 14, 2018	Jan. 31, 2017	Oct. 27, 2009	Mar. 31, 2019	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	Sep. 13, 2018	Aug. 21, 2018	Jul. 31, 2017	Aug. 04, 2014	Dec. 31, 2012	Oct. 14, 2009	Aug. 21, 2009
Schedule of Equity Method Investments [Line Items]
Aggregate fair value of investments as of Effective Date																					$ 2,224,000,000
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity						$ 636,000,000								$ 636,000,000
Weighted average remaining useful life, years														15 years
Equity method investments						1,238,457,000				$ 1,254,198,000				$ 1,238,457,000	$ 1,254,198,000
Income on equity investments, net						45,249,000	$ 32,381,000	$ 52,568,000	$ 39,137,000	38,506,000	$ 21,058,000	$ 40,761,000	$ 37,037,000	169,335,000	137,362,000	$ 148,156,000
Distributions from equity investments														171,591,000	198,124,000	170,527,000
Write-downs of investments														0	(191,000,000)	0
Realized Gain (Loss) on Marketable Securities, Cost Method Investments, and Other Investments														4,000,000
Cost-method Investments, Other than Temporary Impairment															(3,000,000)
Proceeds from sales of investments														15,232,000	148,321,000	0
Gain (Loss) on Investments, Excluding Other than Temporary Impairments														(1,113,000)	8,131,000	0
Deferred Tax Liabilities, Investments						$ 213,887,000				209,751,000				$ 213,887,000	209,751,000
Television Food Network, G.P.
Schedule of Equity Method Investments [Line Items]
Ownership in equity method investment, percent						31.00%								31.00%
Equity method investments						$ 1,228,000,000				$ 1,234,000,000				$ 1,228,000,000	1,234,000,000
Income on equity investments, net														160,000,000	141,000,000	122,000,000
Distributions from equity investments														166,000,000	$ 186,000,000	158,000,000
CareerBuilder, LLC
Schedule of Equity Method Investments [Line Items]
Ownership in equity method investment, percent										6.00%		32.00%			6.00%		6.00%		7.00%
Equity method investments										$ 10,000,000					$ 10,000,000
Income on equity investments, net		$ 11,000,000												10,000,000	(2,000,000)	27,000,000
Distributions from equity investments		$ 5,000,000									16,000,000			6,000,000	16,000,000	13,000,000
Sale of partial interest of equity method investment							11,000,000				$ 158,000,000
Pretax gain (loss) recognized on sale of equity method investment							$ (5,000,000)							$ (5,000,000)	4,000,000
Write-downs of investments															(181,000,000)
Dose Media, LLC
Schedule of Equity Method Investments [Line Items]
Ownership in equity method investment, percent						23.00%								23.00%
Equity method investments						$ 0								$ 0
Income on equity investments, net															(2,000,000)	$ (3,000,000)
Write-downs of investments										(10,000,000)
Tribune Publishing
Schedule of Equity Method Investments [Line Items]
Tribune Publishing common stock retained, shares																				381,354
Investment Ownership Percentage																				1.50%
Proceeds from Sale and Maturity of Marketable Securities			$ 5,000,000
Realized Gain (Loss) on Marketable Securities, Cost Method Investments, and Other Investments													$ 5,000,000		$ 5,000,000
Other Equity Investment [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds from sales of investments														4,000,000
Gain (Loss) on Investments, Excluding Other than Temporary Impairments														4,000,000
Comcast SportsNet Chicago, LLC
Schedule of Equity Method Investments [Line Items]
Investment Ownership Percentage																							25.34%
New Cubs LLC
Schedule of Equity Method Investments [Line Items]
Distribution from cost investment				$ 705,000,000
Cost method investment, accounts receivables and other items retained by Company																						$ 740,000,000
CEV LLC
Schedule of Equity Method Investments [Line Items]
Investment Ownership Percentage				5.00%														5.00%
Investment owned, percent				95.00%
Cost Method Investments, Additional Information															5000000	2500000
Cost method investments						20,000,000				22,000,000				20,000,000	$ 22,000,000
Deferred Tax Liabilities, Investments						69,000,000				96,000,000				69,000,000	96,000,000
Revaluation of Assets
Schedule of Equity Method Investments [Line Items]
Fair value adjustments to investments																					1,615,000,000
Company's share of increases in carrying value of investees' amortization intangible assets																					1,108,000,000
Company's share of increases attributable to goodwill and other identifiable intangibles not subject to amortization																					$ 507,000,000
Payment Guarantee | New Cubs LLC
Schedule of Equity Method Investments [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted						$ 249,000,000				$ 699,000,000				$ 249,000,000	$ 699,000,000
Subsequent Event | CEV LLC
Schedule of Equity Method Investments [Line Items]
Investment Ownership Percentage	5.00%
Proceeds from sales of investments	$ 107,500,000
Gain (Loss) on Investments, Excluding Other than Temporary Impairments					$ 86,000,000