Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Reconciliation Between Earnings Per Share

The following table provides a reconciliation between basic and diluted earnings per share for the years ended December 31:

Millions, Except Per Share Amounts	2019		2018		2017
Net income	$	5,919	$	5,966	$	10,712
Weighted-average number of shares outstanding:
Basic		703.5		750.9		798.4
Dilutive effect of stock options		1.2		1.9		1.8
Dilutive effect of retention shares and units		1.4		1.5		1.5
Diluted		706.1		754.3		801.7
Earnings per share – basic	$	8.41	$	7.95	$	13.42
Earnings per share – diluted	$	8.38	$	7.91	$	13.36