Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 1,190	$ 1,253
Other comprehensive income:
Change in pension and retiree health and welfare benefits, net of tax	0	63
Change in accumulated other comprehensive income (loss) of equity method investees	1	(1)
Other comprehensive income (loss), net of tax	1	62
Total comprehensive income	$ 1,191	$ 1,315