Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 5,481	$ 5,219	$ 11,300
Other comprehensive income:
Change in pension and retiree health and welfare benefits, net of taxes	16	(127)	112
Change in accumulated other comprehensive income (loss) of equity method investees	(1)	1	0
Other comprehensive income (loss), net of tax	15	(126)	112
Total comprehensive income	$ 5,496	$ 5,093	$ 11,412