Supplemental cash flow information (Tables)

12 Months Ended

Dec. 31, 2020

Supplemental Cash Flow Elements [Abstract]

Schedule of supplemental cash flow information

A summary of supplemental cash flow information for each of the three years ending December 31, 2020 is presented in the following table (in millions).

	2020		2019		2018
Cash paid during the period for:
Income taxes	$	5,001	$	5,415	$	4,354
Interest:
Insurance and other		1,001		1,011		1,111
Railroad, utilities and energy		3,006		2,879		2,867
Non-cash investing and financing activities:
Liabilities assumed in connection with business acquisitions		6,981		766		3,735
Operating lease liabilities arising from obtaining right-of-use assets		729		782		—