Financial Instruments (Carrying Amount of Equity Securities) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Total sale price	$ 2,629	$ 590	$ 3,353	$ 1,499
Total initial cost	409	424	766	685
Cumulative net gains	(2,220)	$ (166)	(2,587)	$ (814)
Marketable Securities
Total initial cost	2,662		2,662		$ 2,227
Cumulative net gain (loss)	4,208		4,208		3,631
Carrying value	6,870		6,870		5,858
Non-Marketable Securities
Total initial cost	14,743		14,743		14,616
Cumulative net gain (loss)	8,730		8,730		4,277
Carrying value	23,473		23,473		18,893
Total
Total initial cost	17,405		17,405		16,843
Cumulative net gain (loss)	12,938		12,938		7,908
Carrying value	30,343		30,343		24,751
Cumulative loss from equity derivatives	684
Cumulative net gain of non-marketable securities	10,400		10,400		6,100
Unrealized loss of non-marketable securities	1,700		1,700		1,900
Other Noncurrent Assets
Marketable Securities
Carrying value	$ 591		$ 591		$ 429