Investments (Investment and Other Income (Loss), Net) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Investment and Other Income (Loss), Net [Line Items]
Equity in net income (losses) of investees, net	$ 262	$ (49)
Realized and unrealized gains (losses) on equity securities, net	214	28
Other income (loss), net	200	147
Investment and other income (loss), net	676	126
NBCUniversal Media LLC [Member]
Investment and Other Income (Loss), Net [Line Items]
Equity in net income (losses) of investees, net	(120)	(100)
Realized and unrealized gains (losses) on equity securities, net	161	37
Other income (loss), net	199	59
Investment and other income (loss), net	$ 240	$ (4)

Nonoperating income (losses), net recorded in the income statement that are not separately stated.

No definition available.

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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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