Capital contribution to a VIE recorded in the current period to be paid in a future period.

No definition available.

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- Definition

The aggregate principal amount of the debt being exchanged in a debt exchange transaction.

+ References

No definition available.

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- Definition

[Line Items] for Supplemental Financial Information [Table]

+ References

No definition available.

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- Definition

Future cash outflow to pay for purchases of fixed assets that have occurred.

+ References

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-Topic 230
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Balance Type:	credit
Period Type:	duration

- Definition

Value of property contributed in noncash investing and financing activities.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

+ References

+ Details

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Period Type:	instant

- Definition

Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

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Period Type:

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Supplemental Financial Information (Noncash Investing and Financing Activities) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Financial Information [Line Items]
Property and equipment and intangible assets accrued but not yet paid			$ 2,100	$ 1,200	$ 1,300
Dividends payable		$ 732	$ 860	$ 732	$ 653
Dividends payable (in dollars per share)		$ 0.1575	$ 0.19	$ 0.1575	$ 0.1375
Capital contribution accrued but not yet paid					$ 447
NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Property and equipment and intangible assets accrued but not yet paid			$ 1,400	$ 325	$ 189
Senior Notes Exchange [Member] \| Senior Notes [Member] \| Comcast and NBCUniversal Senior Notes [Member]
Supplemental Financial Information [Line Items]
Aggregate principal amount issued		$ 5,500		$ 5,500
Aggregate principal amount of certain series of outstanding notes		$ 3,900
Senior Notes Exchange [Member] \| Senior Notes [Member] \| Comcast and NBCUniversal Senior Notes [Member] \| NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Aggregate principal amount of certain series of outstanding notes	$ 3,900
Universal Beijing Resort [Member]
Supplemental Financial Information [Line Items]
Assets contributed to variable interest entity			391
Universal Beijing Resort [Member] \| NBCUniversal Media LLC [Member]
Supplemental Financial Information [Line Items]
Assets contributed to variable interest entity			$ 391