Condensed Consolidated Statements of Financial Position - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 1,115	$ 1,799
Short-term investments (Note 13)	46	60
Accounts receivable, net (Note 10)	1,666	1,505
Materials and supplies	688	638
Other current assets	249	212
Total current assets	3,764	4,214
Investments	2,277	2,164
Properties, net (Note 11)	54,148	54,161
Operating lease assets	1,635	1,610
Other assets	249	249
Total assets	62,073	62,398
Current liabilities:
Accounts payable and other current liabilities (Note 12)	3,247	3,104
Debt due within one year (Note 14)	1,110	1,069
Total current liabilities	4,357	4,173
Debt due after one year (Note 14)	27,702	25,660
Operating lease liabilities	1,256	1,283
Deferred income taxes	12,389	12,247
Other long-term liabilities	2,066	2,077
Commitments and contingencies (Note 15)
Total liabilities	47,770	45,440
Common shareholders' equity:
Common shares, $2.50 par value, 1,400,000,000 authorized; 1,112,456,322 and 1,112,227,784 issued; 652,954,892 and 671,351,360 outstanding, respectively	2,781	2,781
Paid-in-surplus	4,499	4,864
Retained earnings	53,116	51,326
Treasury stock	(44,542)	(40,420)
Accumulated other comprehensive loss (Note 9)	(1,551)	(1,593)
Total common shareholders' equity	14,303	16,958
Total liabilities and common shareholders' equity	$ 62,073	$ 62,398