Fair Value Measurements and Financial Instruments - Fair Value of Short-term and Long-term Debt (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	$ 81,552	$ 86,806
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	55,464	58,804
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	0	0
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	141,665	148,583
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument fair value	$ 137,016	$ 145,610