Equity Method Investments (Reconciliation Of Investments In Equity Affiliates) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Beginning of year	$ 6,245	$ 1,560
Additional investments	448	237
Time Warner investments acquired	0	4,912
Equity in net income (loss) of affiliates	(6)	48	$ 128
Dividends and Distributions received	(301)	(243)
Currency translation adjustments	(10)	(14)
Other adjustments	(35)	7
End of year	3,695	6,245	$ 1,560
Hudson Yards North Tower Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Disposition of investments	1,681	0
Hulu [Member]
Schedule of Equity Method Investments [Line Items]
Disposition of investments	689	0
Game Show Network [Member]
Schedule of Equity Method Investments [Line Items]
Disposition of investments	288	0
Otter Media [Member]
Schedule of Equity Method Investments [Line Items]
Acquisition of remaining interest in Otter Media	$ 0	$ (166)

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This item represents disclosure of additional investments made during the period.

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Represents the purchase by the parent of an additional equity interest in a subsidiary during the period, thereby effecting a change in total (consolidated) equity attributable to the parent. The purchase of the additional equity interest represented by this element increases the parent's controlling interest in the subsidiary.

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Represents a sale by the parent of a portion of its equity interest in a subsidiary during the period, thereby effecting a change in total (consolidated) equity attributable to the parent. The sale of the equity interest represented by this element does not result in a loss of control by the parent.

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Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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