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Investments (Schedule of Investments) (Details) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Schedule of Investments [Line Items] |  |
Equity method | $ 5,347 | $ 4,035
Marketable equity securities | 353 | 341
Nonmarketable equity securities | 1,896 | 1,805
Other investments | 1,796 | 1,796
Total investments | 9,392 | 7,977
Less: Current investments | 1,709 | 94
Less: Investment securing collateralized obligation | 694 | 0
Noncurrent investments | 6,989 | 7,883
NBCUniversal Media LLC [Member] |  |
Schedule of Investments [Line Items] |  |
Equity method | 1,156 | 707
Marketable equity securities | 295 | 162
Nonmarketable equity securities | 804 | 811
Total investments | 2,255 | 1,680
Less: Current investments | 1 | 0
Less: Investment securing collateralized obligation | 694 | 0
Noncurrent investments | $ 1,560 | $ 1,680

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