Leases - Lease Position (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets
Operating lease assets	$ 7,237	$ 5,733
Finance lease assets	1,596	1,002
Total lease assets	$ 8,833	$ 6,735
Finance lease asset, balance sheet	Property and equipment, net of accumulated depreciation and amortization of $18,671 and $17,511	Property and equipment, net of accumulated depreciation and amortization of $18,671 and $17,511
Liabilities
Current operating lease liabilities	$ 703	$ 678
Current finance lease liabilities	280	289
Noncurrent operating lease liabilities	7,056	5,713
Noncurrent finance lease liabilities	1,556	894
Total lease liabilities	$ 9,595	$ 7,574
Operating leases, weighted-average remaining lease term	13 years	12 years
Finance leases, weighted-average remaining lease term	6 years	5 years
Operating leases, weighted-average discount rate	3.81%	4.88%
Finance leases, weighted-average discount rate	3.36%	3.61%
Finance lease liability, current, balance sheet	Current maturities of debt and finance leases	Current maturities of debt and finance leases
Finance lease liability, noncurrent, balance sheet	Debt and finance leases	Debt and finance leases