Leases (Supplemental Balance Sheet Information Related to Leases) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Operating Leases
Operating lease right-of-use assets	$ 21,782	$ 21,824
Accounts payable and accrued liabilities	$ 3,468	$ 3,393
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accounts payable and accrued liabilities	Accounts payable and accrued liabilities
Operating lease obligation	$ 18,741	$ 18,956
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Operating lease obligation	Operating lease obligation
Total operating lease obligation	$ 22,209	$ 22,349
Finance Leases
Property, plant and equipment, at cost	2,612	2,494
Accumulated depreciation and amortization	(1,141)	(1,053)
Property, plant and equipment, net	$ 1,471	$ 1,441
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Debt maturing within one year	Debt maturing within one year
Current portion of long-term debt	$ 155	$ 127
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Long-term debt	$ 1,476	$ 1,442
Total finance lease obligation	$ 1,631	$ 1,569
Weighted-Average Remaining Lease Term (years), Operating leases	8 years 1 month 6 days		8 years 2 months 12 days
Weighted-Average Remaining Lease Term (years), Finance leases	7 years 10 months 24 days		9 years
Weighted-Average Discount Rate, Operating leases	3.60%		3.70%
Weighted-Average Discount Rate, Finance leases	7.90%		8.30%