Restructuring Charges - Schedule of Restructuring Charges (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 21	$ 19	$ 49	$ 21	$ 34
Cost of transportation and services
Restructuring Cost and Reserve [Line Items]
Restructuring charges			2	0
Direct operating expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges			1	1
SG&A
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 46	$ 20