Financial Instruments (Measurement Alternative Investments) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Gains and Losses on Marketable and Non-Marketable Equity Securities
Net gain (loss) on equity securities sold during the period	$ (5)	$ (63)	$ 426	$ 381
Net unrealized gain (loss) on equity securities held as of the end of the period	1,904	(1,465)	2,114	1,873
Total gain (loss) recognized in other income (expense), net	1,899	(1,528)	2,540	2,254
Total unrealized gain on non-marketable equity securities	$ 1,198	$ 166	$ 357	$ 1,446