Capital Stock (Tables)

9 Months Ended

Sep. 30, 2017

Capital [Abstract]

Summary of Cash Dividend Activity

A summary of the cash dividend activity for the nine months ended September 30, 2017 and 2016 is as follows:

Declaration Date	Record Date	Payment Date	Cash Dividend per Share	Total
Nine Months Ended September 30, 2017
February 22, 2017	March 10, 2017	March 24, 2017	$0.65	$172.2
April 27, 2017	June 9, 2017	June 23, 2017	$0.65	$171.8
July 25, 2017	September 8, 2017	September 25, 2017	$0.70	$181.4
Nine Months Ended September 30, 2016
February 18, 2016	March 10, 2016	March 25, 2016	$0.65	$170.7
April 26, 2016	June 10, 2016	June 24, 2016	$0.65	$170.9
July 26, 2016	September 9, 2016	September 26, 2016	$0.65	$171.1

Summary of Share Repurchases

A summary of common stock repurchases from October 1, 2017 through October 12, 2017 (subsequent to September 30, 2017) and for the nine months ended September 30, 2017 is as follows:

	October 1, 2017   Through   October 12, 2017		Nine Months Ended   September 30, 2017
Shares repurchased	0.7		8.7
Average price per share	$	191.35	$	186.80
Aggregate cost	$	130.5	$	1,635.4
Authorization remaining at the end of the period	$	2,410.0	$	2,540.5

Summary of Stock Option Activity

A summary of stock option activity for the nine months ended September 30, 2017 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, 2017	5.6		$	102.80
Granted	1.1		167.38
Exercised	(1.8	)	87.22
Forfeited or expired	(0.2	)	136.02
Outstanding at September 30, 2017	4.7		122.55		6.27	$	318.3
Exercisable at September 30, 2017	3.0		106.20		4.89	$	253.8

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, 2017 is as follows:

	Restricted Stock Shares and Units		Weighted- Average Grant Date Fair Value per Share
Nonvested at January 1, 2017	2.1		$	127.68
Granted	0.8		173.62
Vested	(0.8	)	110.12
Forfeited	(0.1	)	147.04
Nonvested at September 30, 2017	2.0		151.64

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, 2017 and 2016:

	Nine Months Ended September 30
	2017		2016
Risk-free interest rate	2.31	%	1.76	%
Volatility factor	32.00	%	32.00	%
Quarterly dividend yield	0.397	%	0.491	%
Weighted-average expected life (years)	4.00		4.10

Schedule of Weighted-Average Fair Values Determined for the Periods

The following weighted-average fair values per option or share were determined for the nine months ended September 30, 2017 and 2016:

	Nine Months Ended September 30
	2017		2016
Options granted during the period	$	40.84	$	30.57
Restricted stock awards granted during the period	173.62		131.88