Segments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information, Profit (Loss)
Operating revenue	$ 7,126	$ 1,468	$ 11,276	$ 10,060
Intersegment Sales/Other | Exchanged products
Segment Reporting Information, Profit (Loss)
Operating revenue	$ (536)	$ (65)	$ (1,039)	$ (895)