Supplemental cash flow information (Tables)

12 Months Ended

Dec. 31, 2019

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, 2019 is presented in the following table (in millions).

	2019		2018		2017
Cash paid during the period for:
Income taxes	$	5,415	$	4,354	$	3,286
Interest:
Insurance and other		1,011		1,111		1,260
Railroad, utilities and energy		2,879		2,867		2,828
Non-cash investing and financing activities:
Liabilities assumed in connection with business acquisitions		766		3,735		747
Right-of-use assets obtained in exchange for new operating lease liabilities		782		—		—
Equity securities surrendered in connection with warrant exercise		—		—		4,965