XML 47 R36.htm IDEA: XBRL DOCUMENT v3.21.2
Valuation of debt and equity investments and certain liabilities - Additional Information (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Credit losses related to available-for-sale investments     $ 0 $ 0  
Proceeds from sales, redemptions and maturities of short-term available-for-sale investments $ 2,460,000,000 $ 1,810,000,000 4,460,000,000 3,200,000,000  
Proceeds from sale of short-term investments       $ 253,000,000  
Level 3          
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]          
Liabilities, fair value 0   0   $ 0
Assets, fair value $ 0   $ 0   $ 0