Leases (Supplemental Balance Sheet Information Related to Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Operating Leases
Operating lease right-of-use assets	$ 20,909	$ 20,905
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accounts payable and accrued liabilities	Accounts payable and accrued liabilities
Accounts payable and accrued liabilities	$ 3,533	$ 3,524
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Operating lease obligation	Operating lease obligation
Operating lease obligation	$ 17,391	$ 17,568
Total operating lease obligation	20,924	21,092
Finance Leases
Property, plant and equipment, at cost	2,449	2,828
Accumulated depreciation and amortization	(1,378)	(1,399)
Property, plant and equipment – net	$ 1,071	$ 1,429
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant and Equipment – Net	Property, Plant and Equipment – Net
Current portion of long-term debt	$ 179	$ 183
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Debt maturing within one year	Debt maturing within one year
Long-term debt	$ 1,237	$ 1,655
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-Term Debt	Long-Term Debt
Total finance lease obligation	$ 1,416	$ 1,838
Weighted-Average Remaining Lease Term (years), Operating leases	7 years 7 months 6 days	7 years 8 months 12 days
Weighted-Average Remaining Lease Term (years), Finance leases	6 years 8 months 12 days	7 years 2 months 12 days
Weighted-Average Discount Rate, Operating leases	4.50%	4.10%
Weighted-Average Discount Rate, Finance leases	8.50%	8.30%