Investments (Schedule of Investments) (Details) - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Schedule of Investments [Line Items] | ||
| Equity method | $ 4,035 | $ 3,546 |
| Marketable equity securities | 341 | 433 |
| Nonmarketable equity securities | 1,805 | 1,186 |
| Other investments | 1,796 | 1,785 |
| Total investments | 7,977 | 6,950 |
| Less: Current investments | 94 | 19 |
| Long-term Investments | 7,883 | 6,931 |
| NBCUniversal Media LLC [Member] | ||
| Schedule of Investments [Line Items] | ||
| Equity method | 707 | 690 |
| Marketable equity securities | 162 | 430 |
| Nonmarketable equity securities | 811 | 696 |
| Total investments | 1,680 | 1,816 |
| Long-term Investments | $ 1,680 | $ 1,816 |
| X | ||||||||||
- Definition 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of investment in equity security without readily determinable fair value. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Sum of the carrying amounts as of the balance sheet date of all investments. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of investments classified as other. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition 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. No definition available.
|
| X | ||||||||||
- Definition Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Details
|