Supplemental cash flow information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Supplemental Cash Flow Information [Line Items]
Cash paid during the period for income taxes	$ 2,962	$ 1,951
Noncash Investing and Financing Items [Abstract]
Liabilities assumed in connection with business acquisitions	10,815	21
Insurance and Other [Member]
Supplemental Cash Flow Information [Line Items]
Cash paid during the period for interest	725	567
Railroad, Utilities and Energy [Member]
Supplemental Cash Flow Information [Line Items]
Cash paid during the period for interest	$ 1,857	$ 1,564