Segments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information, Profit (Loss)
Operating revenue	$ 9,154	$ 3,062	$ 20,429	$ 13,122
Intersegment Sales/Other | Exchanged products
Segment Reporting Information, Profit (Loss)
Operating revenue	$ (629)	$ (249)	$ (1,667)	$ (1,144)