Leases (Supplemental Balance Sheet Information) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Property leases
Operating lease ROU assets	$ 2,661	$ 2,405
Short-term operating lease liabilities	521	555
Long-term operating lease liabilities	2,178	1,884
Operating lease liabilities	$ 2,699	$ 2,439
Weighted average remaining lease term	8 years 4 months 24 days	8 years 2 months 12 days
Weighted average discount rate	4.74%	4.30%
Operating lease, liability, current, statement of financial position [extensible enumeration]	Accounts Payable and Accrued Liabilities, Current	Accounts Payable and Accrued Liabilities, Current