Capital Stock (Tables)

12 Months Ended

Dec. 31, 2019

Capital [Abstract]

Summary of Stock Option Activity

A summary of stock option activity for the year ended December 31, 2019 is as follows:

	Number of Shares		Weighted-Average Option Price per Share		Weighted-Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value
Outstanding at January 1, 2019	3.7		$	149.65
Granted	0.7		306.61
Exercised	(1.2	)	126.10
Forfeited or expired	(0.1	)	241.26
Outstanding at December 31, 2019	3.1		190.31		6.18	$	355
Exercisable at December 31, 2019	2.0		145.37		4.93	$	312

Summary of Nonvested Restricted Stock Activity Including Restricted Stock Units

A summary of the status of nonvested restricted stock activity, including restricted stock units, for the year ended December 31, 2019 is as follows:

	Restricted Stock Shares and Units		Weighted-Average Grant Date Fair Value per Share
Nonvested at January 1, 2019	1.7		$	183.32
Granted	0.6		305.88
Vested	(0.8	)	153.79
Forfeited	(0.1	)	242.38
Nonvested at December 31, 2019	1.4		242.47

Summary of Weighted-Average Assumptions Used to Estimate the Fair Values of Options Granted During the Periods

The following weighted-average assumptions were used to estimate the fair values of options granted during the years ended December 31, 2019, 2018 and 2017:

	2019		2018		2017
Risk-free interest rate	2.69	%	2.90	%	2.31	%
Volatility factor	25.00	%	30.00	%	32.00	%
Dividend yield (annual)	1.00	%	1.30	%	1.60	%
Weighted-average expected life (years)	4.40		3.70		4.00

Schedule of Weighted-Average Fair Values Determined For the Periods

The following weighted-average fair values were determined for the years ending December 31, 2019, 2018 and 2017:

	2019		2018		2017
Options granted during the year	$	68.66	$	55.48	$	40.88
Restricted stock awards granted during the year	305.88		233.73		174.44

Summary of Cash Dividend Activity

A summary of the cash dividend activity for the years ended December 31, 2019 and 2018 is as follows: 

Declaration Date	Record Date	Payment Date	Cash Dividend per Share		Total
Year ended December 31, 2019
January 29, 2019	March 18, 2019	March 29, 2019	$	0.80	$	206
April 23, 2019	June 10, 2019	June 25, 2019	0.80		206
July 23, 2019	September 10, 2019	September 25, 2019	0.80		204
October 22, 2019	December 5, 2019	December 20, 2019	0.80		202
Year ended December 31, 2018
January 30, 2018	March 9, 2018	March 23, 2018	$	0.75	$	192
April 24, 2018	June 8, 2018	June 25, 2018	0.75		196
July 24, 2018	September 10, 2018	September 25, 2018	0.75		195
October 30, 2018	December 5, 2018	December 21, 2018	0.75		193

Summary of Share Repurchases

A summary of common stock repurchases for the years ended December 31, 2019 and 2018 is as follows:

	Years Ended December 31
	2019		2018
Shares repurchased	6.3		6.8
Average price per share	$	268.65	$	248.34
Aggregate cost	$	1,701	$	1,685
Authorization remaining at end of year	$	3,792	$	5,493