Fair Value Measurements Summary of Classification of Equity Securities (Details) - Other Equity Securities - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	$ 14,610	$ 11,039
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable equity securities	11,430	7,069
Prepaid and other current assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable equity securities	986	319
Other long-term assets
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable equity securities	$ 2,194	$ 3,651