Segment Reporting - Selected Financial Data for Each of Operating Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenue	$ 4,221	$ 4,154	$ 11,587	$ 12,512
Operating income (loss)	223	229	163	619
Depreciation and amortization	193	186	572	546
Restructuring expense		11	53	28
Transaction and integration costs	3		93	2
Operating Segments | Transportation
Segment Reporting Information [Line Items]
Revenue	2,675	2,684	7,261	8,090
Operating income (loss)	202	208	307	579
Depreciation and amortization	114	110	337	334
Operating Segments | Logistics
Segment Reporting Information [Line Items]
Revenue	1,580	1,510	4,421	4,530
Operating income (loss)	77	61	72	168
Depreciation and amortization	76	73	225	201
Corporate
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
Operating income (loss)	(56)	(40)	(216)	(128)
Depreciation and amortization	3	3	10	11
Eliminations/Other
Segment Reporting Information [Line Items]
Revenue	(34)	(40)	(95)	(108)
Operating income (loss)	0	0	0	0
Depreciation and amortization	$ 0	$ 0	$ 0	$ 0