Capital Stock (Tables)

9 Months Ended

Sep. 30, 2016

Capital [Abstract]

Summary of Cash Dividend Activity

A summary of the cash dividend activity for the nine months ended September 30, 2016 and 2015 is as follows:

Declaration Date	Record Date	Payment Date	Cash Dividend per Share	Total
Nine Months Ended September 30, 2016
February 18, 2016	March 10, 2016	March 25, 2016	$0.650	$170.7
April 26, 2016	June 10, 2016	June 24, 2016	$0.650	$170.9
July 26, 2016	September 9, 2016	September 26, 2016	$0.650	$171.1
Nine Months Ended September 30, 2015
January 27, 2015	March 10, 2015	March 25, 2015	$0.625	$166.6
April 28, 2015	June 10, 2015	June 25, 2015	$0.625	$163.9
July 28, 2015	September 10, 2015	September 25, 2015	$0.625	$163.0

Summary of Share Repurchases

A summary of common stock repurchases for the nine months ended September 30, 2015 is as follows:

	Nine Months Ended   September 30
	2015
Shares repurchased	10.4
Average price per share	$	145.50
Aggregate cost	$	1,515.8
Authorization remaining at the end of the period	$	4,175.9

Summary of Stock Option Activity

A summary of stock option activity for the nine months ended September 30, 2016 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, 2016	6.0		$	87.23
Granted	1.4		131.89
Exercised	(1.2	)	61.23
Forfeited or expired	(0.3	)	116.81
Outstanding at September 30, 2016	5.9		101.68		5.27	$	174.3
Exercisable at September 30, 2016	4.0		87.16		3.73	$	165.7

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 nine months ended September 30, 2016 is as follows:

	Restricted Stock Shares and Units		Weighted- Average Grant Date Fair Value per Share
Nonvested at January 1, 2016	2.7		$	101.66
Granted	1.0		131.88
Vested	(1.3	)	82.20
Forfeited	(0.2	)	118.56
Nonvested at September 30, 2016	2.2		126.69

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

The following weighted-average assumptions were used to estimate the fair values of options granted during the nine months ended September 30, 2016 and 2015:

	Nine Months Ended September 30
	2016		2015
Risk-free interest rate	1.76	%	1.96	%
Volatility factor	32.00	%	31.00	%
Quarterly dividend yield	0.491	%	0.425	%
Weighted-average expected life (years)	4.10		4.00

Schedule of Weighted-Average Fair Values Determined for the Periods

The following weighted-average fair values were determined for the nine months ended September 30, 2016 and 2015:

	Nine Months Ended September 30
	2016		2015
Options granted during the period	$	30.57	$	34.02
Restricted stock awards granted during the period	131.88		147.22