Significant Accounting Policies - Property Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 33,550	$ 31,306
Accumulated depreciation and amortization	(20,654)	(18,700)
Property and equipment, net	12,896	12,606
Land
Property, Plant and Equipment [Line Items]
Total property and equipment	2,038	2,134
Building and improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	4,225	3,950
Fixtures and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	13,619	13,125
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	6,242	6,077
Software
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 7,426	$ 6,020