Accounting Policies and Supplemental Disclosures - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Accounting Policies [Abstract]
Cash paid for interest on debt	$ 402	$ 279	$ 1,684	$ 1,101
Cash paid for operating leases	2,467	2,367	8,733	7,449
Cash paid for interest on finance leases	81	107	348	471
Cash paid for interest on financing obligations	59	58	208	178
Cash paid for income taxes, net of refunds	619	453	6,201	3,340
Assets acquired under operating leases	3,626	2,175	20,251	24,008
Property and equipment acquired under finance leases, net of remeasurements and modifications	8	166	517	5,160
Property and equipment recognized during the construction period of build-to-suit lease arrangements	131	1,365	1,953	6,324
Property and equipment derecognized after the construction period of build-to-suit lease arrangements, with the associated leases recognized as operating	$ 720	$ 33	$ 5,845	$ 263