Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 1,179	$ 1,105
Net actuarial losses of defined benefit plans:
Adjustments, net of tax effect of $3 and ($2)	(7)	5
Recognized within net income, net of tax effect of ($1) and ($1)	2	2
Derivative instruments:
Change in fair value, net of tax effect of $0 and $0	0	1
Available-for-sale investments:
Unrealized gains (losses), net of tax effect of $0 and $2	(2)	(6)
Other comprehensive income (loss), net of taxes	(7)	2
Total comprehensive income	$ 1,172	$ 1,107