Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows paid for operating leases	$ 2,756	$ 2,689	$ 2,714
Operating cash flows paid for interest portion of finance leases	73	68	62
Financing cash flows paid for principal portion of finance leases	70	62	50
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	1,132	591	1,254
Finance leases	$ (4)
Finance leases		$ 232	$ 278