Financial Instruments (Measurement Alternative Investments) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Gains and Losses on Marketable and Non-Marketable Equity Securities
Net gain on equity securities sold during the period	$ 18	$ 80	$ 233	$ 130
Net unrealized gain (loss) on equity securities held as of the end of the period	1,437	2,619	408	3,652
Total gain recognized in other income (expense), net	1,455	2,699	641	3,782
Total unrealized gain (loss) for non-marketable equity securities	$ 91	$ 890	$ (850)	$ 1,280