Stockholders' Equity - Changes in Stockholders Equity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Changes in Stockholders' Equity
Beginning balance	$ 131,402	$ 114,803	$ 138,245	$ 93,404	$ 138,245	$ 93,404	$ 120,564
Common stock repurchased					(6,000)
Other comprehensive income (loss)	(2,333)	(550)			(5,739)	(895)
Net income (loss)	2,872	3,156			(3,000)	19,041	11,323	$ 26,263
Ending balance	137,489	120,564	131,402	114,803	137,489	120,564	137,489	120,564
Common stock
Changes in Stockholders' Equity
Beginning balance	107	106	106	105	106	105	106
Stock-based compensation and issuance of employee benefit plan stock	0	0			1	1
Ending balance	107	106	107	106	107	106	107	106
Treasury stock
Changes in Stockholders' Equity
Beginning balance	(7,837)	(1,837)	(1,837)	(1,837)	(1,837)	(1,837)	(1,837)
Common stock repurchased	0	0			(6,000)	0
Ending balance	(7,837)	(1,837)	(7,837)	(1,837)	(7,837)	(1,837)	(7,837)	(1,837)
Additional paid-in capital
Changes in Stockholders' Equity
Beginning balance	63,871	48,623	55,437	42,765	55,437	42,765	51,778
Stock-based compensation and issuance of employee benefit plan stock	5,548	3,155			13,982	9,013
Ending balance	69,419	51,778	63,871	48,623	69,419	51,778	69,419	51,778
Accumulated other comprehensive income (loss)
Changes in Stockholders' Equity
Beginning balance	(4,782)	(525)	(1,376)	(180)	(1,376)	(180)	(1,075)
Other comprehensive income (loss)	(2,333)	(550)			(5,739)	(895)
Ending balance	(7,115)	(1,075)	(4,782)	(525)	(7,115)	(1,075)	(7,115)	(1,075)
Retained earnings
Changes in Stockholders' Equity
Beginning balance	80,043	68,436	85,915	52,551	85,915	52,551	71,592
Net income (loss)	2,872	3,156			(3,000)	19,041
Ending balance	$ 82,915	$ 71,592	$ 80,043	$ 68,436	$ 82,915	$ 71,592	$ 82,915	$ 71,592