v3.19.3
Investments and Fair Value Measurement - Unrealized Gain (Loss) on Non-Marketable Securities (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Fair Value Disclosures [Abstract]        
Upward adjustments $ 0 $ 0 $ 22 $ 1,984
Downward adjustments (including impairment) 0 0 0 0
Total unrealized gain for non-marketable equity securities $ 0 $ 0 $ 22 $ 1,984