Description of Business, Accounting Policies, and Supplemental Disclosures - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Cash paid for interest on debt	$ 1,098	$ 916	$ 875
Cash paid for operating leases	6,722	4,475	3,361
Cash paid for interest on finance leases	521	612	647
Cash paid for interest on financing obligations	153	102	39
Cash paid for income taxes, net of refunds	3,688	1,713	881
Assets acquired under operating leases	25,369	16,217	7,870
Property and equipment acquired under finance leases	7,061	11,588	13,723
Property and equipment acquired under build-to-suit lease arrangements	$ 5,616	$ 2,267	$ 1,362