Leases - Operating and Finance Lease Liability Reconciliation (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Total	$ 51,702	$ 44,833
Total	27,613	30,437
Gross lease liabilities	79,315	75,270
Imputed interest - operating leases	(6,419)	(5,734)
Imputed interest - finance leases	(1,943)	(2,003)
Imputed interest	(8,362)	(7,737)
Present value of operating leases	45,283	39,099
Present value of finance leases	25,670	28,434
Present value of lease liabilities	$ 70,953	$ 67,533
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued expenses and other	Accrued expenses and other
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]		Accrued expenses and other
Current portion of operating lease liabilities	$ (5,214)	$ (4,586)
Current portion of finance lease liabilities	(9,442)	(10,374)
Current portion of lease liabilities	(14,656)	(14,960)
Total long-term operating lease liabilities	40,069	34,513
Total long-term finance lease liabilities	16,228	18,060
Total long-term lease liabilities	$ 56,297	$ 52,573
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]