Leases - Components of Lease Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease expense	$ 4,987	$ 6,514	$ 5,921
Financing lease expense:
Amortization of right-of-use assets	684	733	738
Interest on lease liabilities	79	68	69
Total financing lease expense	763	801	807
Variable lease expense	411	484	429
Total lease expense	$ 6,161	$ 7,799	$ 7,157