Stockholders' Equity - Changes in Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Stockholders' equity	$ 73,728	$ 53,061	$ 73,728	$ 53,061	$ 73,728	$ 53,061	$ 65,272	$ 62,060	$ 48,410	$ 43,549
Other comprehensive income (loss)	608	50	(469)	75
Net Income	5,243	2,625	7,778	6,186	13,180	12,096
Common stock
Stockholders' equity	5	5	5	5	5	5		5		5
Treasury stock
Stockholders' equity	(1,837)	(1,837)	(1,837)	(1,837)	(1,837)	(1,837)		(1,837)		(1,837)
Additional paid-in capital
Stockholders' equity	38,017	30,035	38,017	30,035	38,017	30,035	35,412	33,658	28,059	26,791
Stock-based compensation and issuance of employee benefit plan stock	2,605	1,976	4,359	3,244
Accumulated other comprehensive income (loss)
Stockholders' equity	(1,455)	(960)	(1,455)	(960)	(1,455)	(960)	(2,063)	(986)	(1,010)	(1,035)
Other comprehensive income (loss)	608	50	(469)	75
Retained earnings
Stockholders' equity	38,998	25,818	38,998	25,818	$ 38,998	$ 25,818	$ 33,755	31,220	$ 23,193	19,625
Net Income	$ 5,243	$ 2,625	$ 7,778	$ 6,186
Retained earnings | Revision of Prior Period, Adjustment
Stockholders' equity								$ 0		$ 7