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Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Debt Instrument [Line Items]
Total debt	$ 64,600
Fair value of debt	66,000
Repurchases and repayments of debt	4,347	$ 4,967
NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Total debt	12,500
Fair value of debt	12,700
Repurchases and repayments of debt	332	$ 3,402
Universal Beijing Resort Term Loans [Member] | NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Debt face amount	235
Universal Studios Japan Term Loans [Member]
Debt Instrument [Line Items]
Repurchases and repayments of debt	318
Universal Studios Japan Term Loans [Member] | NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Repurchases and repayments of debt	$ 318

X

- Definition

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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