Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 1,466	$ 1,393	$ 4,057	$ 3,847
Other comprehensive income:
Change in pension and retiree health and welfare benefits, net of tax	0	(1)	63	(1)
Change in accumulated other comprehensive income (loss) of equity method investees	0	0	(1)	1
Other comprehensive income (loss), net of tax	0	(1)	62	0
Total comprehensive income	$ 1,466	$ 1,392	$ 4,119	$ 3,847