Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

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Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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Fair value portion of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

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Impairment, Number Of Assessments Performed

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Indefinite-lived Intangible Assets, Percent Of Carrying Value

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Number Of Markets With Book Value Of FCC Licenses

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Number Of Television Markets, Impaired

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Number Of Television Markets, Quantitative Impairment Test

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Goodwill and Other Intangible Assets (Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($) market	Jun. 30, 2020 USD ($) market	Dec. 31, 2020 USD ($) market reportingunit assessment	Dec. 31, 2019 USD ($)
Impairment Testing Assumptions [Line Items]
Number of reporting units \| reportingunit			4
Number of assessments performed \| assessment			10
Number of television markets \| market	4	3
Impairment charge \| $			$ 25	$ 20
FCC Licenses Impairment Test [Member]
Impairment Testing Assumptions [Line Items]
Number of markets lower than carrying value \| market		2
Estimated fair value fair value \| $		$ 216
Indefinite-lived intangible assets \| $	$ 269	$ 53	$ 269
Percentage of fair value in excess of carrying amount	20.00%	7.00%	20.00%
Percent of carrying value	10.00%		10.00%
FCC Licenses Impairment Test Television Stations [Member]
Impairment Testing Assumptions [Line Items]
Number of markets with book value of FCC licenses \| market			14