Intangible Assets (Indefinite-Lived Intangible Assets) (Details)	3 Months Ended
	Jun. 30, 2019 USD ($)
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets, Period Start	$ 41,465,000,000
Indefinite-lived Intangible Assets, Period End	41,474,000,000
Goodwill, beginning balance	4,598,000,000
Goodwill, Period Increase (Decrease)	0
Goodwill, ending balance	4,598,000,000
Total indefinite-lived intangible assets including FCC licenses, Trademarks, Goodwill, beginning balance	46,063,000,000
Indefinite lived intangible assets period increase decrease	9,000,000
Total indefinite-lived intangible assets including FCC licenses, Trademarks, Goodwill, ending balance	46,072,000,000
Goodwill, Impairment Loss	2,000,000,000.0
Goodwill, Impaired, Accumulated Impairment Loss	0
FCC Licenses [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets, Period Start	37,430,000,000
Indefinite-lived Intangible Assets, Period Increase (Decrease)	9,000,000
Indefinite-lived Intangible Assets, Period End	37,439,000,000
Trademarks [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets, Period Start	4,035,000,000
Indefinite-lived Intangible Assets, Period Increase (Decrease)	0
Indefinite-lived Intangible Assets, Period End	$ 4,035,000,000