Fair Value Measurements and Financial Instruments - Debt Excluding Capital Leases (Detail) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	$ 150,971	$ 148,906
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	144,922	139,041
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	86,908	84,385
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	58,014	54,656
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	$ 0	$ 0