Significant Accounting Policies - Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables	$ 11,908	$ 8,983
Vendor and manufacturer receivables	15,711	12,395
Premium receivables	3,714	2,676
Other receivables	3,894	3,449
Accounts receivable, net	35,227	27,276
Total accounts receivable, net		27,503
Allowance for credit losses	$ 343	333
Disposal Group, Held-for-sale, Not Discontinued Operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable, net		$ 227