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Financial Instruments and Fair Value Measurements (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) market	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) market	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Derivative [Line Items]
Carrying value of notes and debentures	$ 19,930		$ 19,930		$ 17,980
Fair value of debt	23,200		23,200		20,600
Investments without readily determinable fair value	104		104		113
Unrealized gain	32		32
Proceeds from sale of marketable securities			146
Gain on marketable securities		$ 28		$ 66
Impairment charges	25	$ 0		$ 0
TV Entertainment Segment [Member] \| Depreciation and Amortization [Member]
Derivative [Line Items]
Impairment charges	$ 25		$ 25
FCC License Impairment Test [Member]
Derivative [Line Items]
Number of markets lower than carrying value \| market	2		2
Cash Flow Hedging [Member] \| Foreign exchange contract [Member]
Derivative [Line Items]
Maximum derivative contract term			24 months
Notional amount of derivative	$ 881		$ 881		1,440
Cash Flow Hedging [Member] \| Foreign exchange contract [Member] \| Future Production Costs [Member]
Derivative [Line Items]
Notional amount of derivative	421		421		833
Cash Flow Hedging [Member] \| Foreign exchange contract [Member] \| Other Foreign Currency [Member]
Derivative [Line Items]
Notional amount of derivative	$ 460		$ 460		$ 606