Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 5,990	$ 5,161	$ 5,481
Other comprehensive income:
Change in pension and retiree health and welfare benefits, net of tax	255	(48)	16
Change in accumulated other comprehensive income (loss) of equity method investees	0	1	(1)
Other comprehensive income (loss), net of tax	255	(47)	15
Total comprehensive income	$ 6,245	$ 5,114	$ 5,496