Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Supplemental Balance Sheet Information Related to Leases [Line Items]
Operating lease ROU assets	$ 2,654	$ 2,405
Short-term operating lease liabilities	576	555
Long-term operating lease liabilities	$ 2,117	$ 1,884
Weighted average discount rate	3.68%	1.82%
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities, Current	Accounts Payable and Accrued Liabilities, Current
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Vehicles, net	Vehicles, net
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Total	Total
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Operating lease ROU assets	Operating lease ROU assets
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Operating lease ROU assets	Operating lease ROU assets
Property leases
Supplemental Balance Sheet Information Related to Leases [Line Items]
Operating lease ROU assets	$ 2,654	$ 2,405
Short-term operating lease liabilities	576	555
Long-term operating lease liabilities	2,117	1,884
Operating lease liabilities	$ 2,693	$ 2,439
Weighted average remaining lease term	8 years 1 month 6 days	8 years 2 months 12 days
Weighted average discount rate	4.83%	4.30%
Vehicle leases
Supplemental Balance Sheet Information Related to Leases [Line Items]
Operating lease ROU assets	$ 117	$ 86
Short-term operating lease liabilities	83	64
Long-term operating lease liabilities	36	22
Operating lease liabilities	$ 119	$ 86
Weighted average remaining lease term	1 year 6 months	1 year 4 months 24 days
Weighted average discount rate	5.13%	4.86%
Finance lease ROU assets, gross	$ 265	$ 267
Accumulated amortization	(41)	(45)
Finance Lease ROU assets, net	224	222
Short-term vehicle finance lease liabilities	59	44
Long-term vehicle finance lease liabilities	113	132
Total	$ 172	$ 176
Weighted average remaining lease term	2 years 9 months 18 days	2 years
Weighted average discount rate	3.68%	1.82%