Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 1,709	$ 2,295	$ 5,139	$ 6,787
Net actuarial losses of defined benefit plans:
Adjustments, net of tax effect of ($3) and ($4); ($4) and $2	6	11	6	(23)
Recognized within net income, net of tax effect of ($1) and ($4); ($3) and ($9)	3	15	9	33
Prior service cost (credit) of defined benefit plans:
Adjustments, net of tax effect of $0 and $0; $0 and $0	0	1	0	1
Recognized within net income, net of tax effect of $0 and $0; $0 and $0	1	(1)	1	(1)
Derivative instruments:
Change in fair value, net of tax effect of $0 and $0; $0 and $0	0	1	1	1
Available-for-sale investments:
Unrealized gains (losses), net of tax effect of $0 and $0; $0 and $2	1	(1)	2	(8)
Other comprehensive income (loss), net of taxes	11	26	19	3
Total comprehensive income	$ 1,720	$ 2,321	$ 5,158	$ 6,790