Long-Term Debt	3 Months Ended
Long-Term Debt	Mar. 31, 2019
Debt Instrument [Line Items]
Long-Term Debt	Long-Term Debt As of March 31, 2019, our debt had a carrying value of $109.1 billion and an estimated fair value of $115.8 billion. The estimated fair value of our publicly traded debt was primarily based on Level 1 inputs that use quoted market values for the debt. The estimated fair value of debt for which there are no quoted market prices was based on Level 2 inputs that use interest rates available to us for debt with similar terms and remaining maturities. Debt Borrowings and Repayments For the three months ended March 31, 2019, we had borrowings of $222 million related to the Universal Beijing Resort term loans. For the three months ended March 31, 2019, we made debt repayments of $2.1 billion primarily related to our dollar-denominated term loan due 2022. Revolving Credit Facilities For the three months ended March 31, 2019, we made net repayments of $615 million under Sky’s £1 billion revolving credit facility due 2021, which was terminated in February 2019. As of March 31, 2019, there were no amounts outstanding under our revolving credit facilities. Amounts available under our revolving credit facilities, net of amounts outstanding under our commercial paper programs and outstanding letters of credit and bank guarantees, totaled $9.2 billion. Commercial Paper Programs For the three months ended March 31, 2019, we made net repayments of $673 million under our commercial paper programs. As of March 31, 2019, we had no commercial paper outstanding. Guarantee Structure Comcast, Comcast Cable and NBCUniversal have fully and unconditionally guaranteed each other’s debt securities, including the Comcast revolving credit facility. As of March 31, 2019, the principal amount of debt securities within the cross-guarantee structure totaled $92.3 billion. Comcast and Comcast Cable fully and unconditionally guarantee NBCUniversal Enterprise’s $3.0 billion aggregate principal amount of senior notes, its revolving credit facility and its commercial paper program. NBCUniversal does not guarantee the NBCUniversal Enterprise senior notes, revolving credit facility or commercial paper program. Comcast Parent provides an unconditional guarantee of the Universal Studios Japan yen-denominated ¥385 billion (approximately $3.5 billion using exchange rates as of March 31, 2019) term loans with a final maturity of March 2022. None of Comcast, Comcast Cable nor NBCUniversal guarantee the ¥5.5 billion RMB ($815 million using exchange rates as of March 31, 2019) principal amount of Universal Beijing Resort term loans outstanding. In March 2019, Sky announced a series of consent solicitations for holders of all of its outstanding debt (approximately $10.0 billion using exchange rates as of March 31, 2019). If all of the consent solicitations are successful, Comcast Parent will provide a full and unconditional guarantee of the Sky notes in exchange for noteholders consenting to (i) the transfer of the listing of three series of notes from the Main Market of the London Stock Exchange to the Professional Securities Market of the London Stock Exchange and (ii) amending certain terms of the Sky notes.
NBCUniversal Media LLC [Member]
Debt Instrument [Line Items]
Long-Term Debt	Long-Term Debt As of March 31, 2019, our debt, excluding our revolving credit agreement with Comcast, had a carrying value of $13.1 billion and an estimated fair value of $13.7 billion. The estimated fair value of our publicly traded debt was primarily based on Level 1 inputs that use quoted market values for the debt. The estimated fair value of debt for which there are no quoted market prices was based on Level 2 inputs that use interest rates available to us for debt with similar terms and remaining maturities. For the three months ended March 31, 2019, Universal Beijing Resort borrowed $222 million under its debt financing agreement to fund the construction of a Universal theme park and resort in Beijing, China (see Note 5). For the three months ended March 31, 2019, we repaid $45 million of Universal Studios Japan term loans maturing 2022. Guarantee Structure We, Comcast and a 100% owned cable holding company subsidiary of Comcast (“CCCL Parent”) have fully and unconditionally guaranteed each other’s debt securities, including the $7.6 billion Comcast revolving credit facility due 2021. As of March 31, 2019, $84.6 billion principal amount of outstanding debt securities of Comcast and CCCL Parent were subject to the cross-guarantee structure. We do not, however, guarantee the obligations of NBCUniversal Enterprise with respect to its $3.0 billion aggregate principal amount of senior notes, its revolving credit facility, its commercial paper program, nor its $725 million liquidation preference of Series A cumulative preferred stock. The Universal Studios Japan term loans are not subject to the cross-guarantee structure, however they have a separate guarantee from Comcast. The Universal Beijing Resort term loans are not guaranteed.