Acquisitions, Dispositions, and Deconsolidations - Broadcasting Acquisitions (Details) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($)
Broadcasting
Business Acquisition [Line Items]
Consideration paid	$ 71.4

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
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-Section 30
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