Capital Stock

Use of Capital – Dividends and Stock Repurchase Program

We regularly review the appropriate use of capital, including acquisitions, common stock and debt security repurchases and dividends to shareholders. The declaration and payment of any dividends or repurchases of our common stock or debt is at the discretion of our Board of Directors and depends upon our financial condition, results of operations, future liquidity needs, regulatory and capital requirements and other factors deemed relevant by our Board of Directors.

A summary of the cash dividend activity for the three months ended March 31, 2017 and 2016 is as follows:



Declaration Date	Record Date	Payment Date	Cash Dividend per Share	Total
Three Months Ended March 31, 2017
February 22, 2017	March 10, 2017	March 24, 2017	$0.65	$172.2

Three Months Ended March 31, 2016
February 18, 2016	March 10, 2016	March 25, 2016	$0.65	$170.7

Under our Board of Directors’ authorization, we maintain a common stock repurchase program. On October 2, 2014, the Board of Directors authorized a $5,000.0 increase to the common stock repurchase program. Repurchases may be made from time to time at prevailing market prices, subject to certain restrictions on volume, pricing and timing. The repurchases are effected from time to time in the open market, through negotiated transactions, including accelerated share repurchase agreements, and through plans designed to comply with Rule 10b5-1 under the Securities Exchange Act of 1934, as amended. Our stock repurchase program is discretionary as we are under no obligation to repurchase shares. We repurchase shares under the program when we believe it is a prudent use of capital. The excess cost of the repurchased shares over par value is charged on a pro rata basis to additional paid-in capital and retained earnings.

A summary of common stock repurchases from April 1, 2017 through April 13, 2017 (subsequent to March 31, 2017) and for the three months ended March 31, 2017 is as follows:



	April 1, 2017 Through April 13, 2017		Three Months Ended March 31, 2017
Shares repurchased	0.2		0.3
Average price per share	$	166.04	$	160.81
Aggregate cost	$	31.9	$	50.7
Authorization remaining at the end of the period	$	4,093.3	$	4,125.2

There were no common stock repurchases during the three months ended March 31, 2016.

Equity Units

We have 25.0 Equity Units with an aggregate principal amount of $1,250.0. For additional information relating to the Equity Units, see Note 10, “Debt.”

Stock Incentive Plans

A summary of stock option activity for the three months ended March 31, 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		166.95
Exercised	(1.1	)	83.14
Forfeited or expired	(0.1	)	107.37
Outstanding at March 31, 2017	5.5		119.24		6.52	$	254.8
Exercisable at March 31, 2017	3.1		96.31		4.58	$	217.3

A summary of the status of nonvested restricted stock activity, including restricted stock units, for the three months ended March 31, 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	0.5		166.94
Vested	(0.7	)	109.02
Forfeited	—		133.09
Nonvested at March 31, 2017	1.9		145.67

Fair Value

We use a binomial lattice valuation model to estimate the fair value of all stock options granted. For a more detailed discussion of our stock incentive plan fair value methodology, see Note 14, “Capital Stock,” to our audited consolidated financial statements as of and for the year ended December 31, 2016 included in our 2016 Annual Report on Form 10-K.

The following weighted-average assumptions were used to estimate the fair values of options granted during the three months ended March 31, 2017 and 2016:



	Three Months Ended March 31
	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

The following weighted-average fair values were determined for the three months ended March 31, 2017 and 2016:



	Three Months Ended March 31
	2017		2016
Options granted during the period	$	40.73	$	30.55
Restricted stock awards granted during the period	166.94		131.83