Stockholders' Equity - Changes in Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Changes in Stockholders' Equity
Beginning balance	$ 146,043	$ 138,245	$ 134,001	$ 138,245
Common stock repurchased		(2,700)
Other comprehensive income (loss)	514	(989)
Net income (loss)	3,172	(3,844)	4,294		$ 21,413
Ending balance	154,526	134,001	154,526	146,043	134,001
Common stock
Changes in Stockholders' Equity
Beginning balance	108	106	107	106
Stock-based compensation and issuance of employee benefit plan stock	0	1
Ending balance	108	107	108	108	107
Treasury stock
Changes in Stockholders' Equity
Beginning balance	(7,837)	(1,837)	(4,503)	(1,837)
Common stock repurchased	0	(2,666)
Ending balance	(7,837)	(4,503)	(7,837)	(7,837)	(4,503)
Additional paid-in capital
Changes in Stockholders' Equity
Beginning balance	75,066	55,437	58,691	55,437
Stock-based compensation and issuance of employee benefit plan stock	4,797	3,254
Ending balance	79,863	58,691	79,863	75,066	58,691
Accumulated other comprehensive income (loss)
Changes in Stockholders' Equity
Beginning balance	(4,487)	(1,376)	(2,365)	(1,376)
Other comprehensive income (loss)	514	(989)
Ending balance	(3,973)	(2,365)	(3,973)	(4,487)	(2,365)
Retained earnings
Changes in Stockholders' Equity
Beginning balance	83,193	85,915	82,071	85,915
Net income (loss)	3,172	(3,844)
Ending balance	$ 86,365	$ 82,071	$ 86,365	$ 83,193	$ 82,071