Earnings Per Share

The following table sets forth the computation of basic earnings per share and earnings per share, assuming dilution:



	Third Quarters				Nine Months
	2017		2016		2017			2016
Numerator (Dollars in millions):
Net Earnings	$	459	$	455	$	1,331		$	1,256
Dividend Equivalents on Restricted Stock	—		—		(1		)	(1		)
Net Earnings, Attributable to Common Shareholders	$	459	455		$	1,330		1,255

Denominator (Units in millions):
Average Common Shares Outstanding	902		942		916			952
Other Potentially Dilutive Common Shares	4		1		3			1
Average Common Shares Outstanding, Assuming Dilution	906		943		919			953

Net Earnings Per Share, Basic	$	0.51	$	0.48	$	1.45		$	1.32
Net Earnings Per Share, Assuming Dilution	$	0.51	$	0.48	$	1.45		$	1.32

Basic earnings per share is based on the weighted-average number of shares of common stock outstanding. Earnings per share, assuming dilution, is based on the weighted-average number of shares of common stock equivalents outstanding adjusted for the effects of common stock that may be issued as a result of potentially dilutive instruments. CSX's potentially dilutive instruments are made up of equity awards, which include long-term incentive awards, and employee stock options.

The Earnings Per Share Topic in the FASB's ASC requires CSX to include additional shares in the computation of earnings per share, assuming dilution. The additional shares included in diluted earnings per share represent the number of shares that would be issued if all of the above potentially dilutive instruments were converted into CSX common stock.

When calculating diluted earnings per share, this rule requires CSX to include the potential shares that would be outstanding if all outstanding stock options were exercised. This number is different from outstanding stock options, which is included in Note 3, Share-Based Compensation, because it is offset by shares CSX could repurchase using the proceeds from these hypothetical exercises to obtain the common stock equivalent. Approximately 10 million and 2.4 million of total average outstanding stock options for the third quarters ended September 30, 2017 and September 23, 2016, respectively, were excluded from the diluted earnings per share calculation because their effect was antidilutive.

Share Repurchases

In July 2017, the Board of Directors approved an additional $500 million of share repurchase authority under the share repurchase program announced in April 2017, bringing the total program size to $1.5 billion. As of October 2, 2017, the Company had completed all share repurchases under this program.

During the third quarters of 2017 and 2016, the Company repurchased approximately $1 billion, or 20 million shares, and $263 million, or 10 million shares, respectively. During the nine months of 2017 and 2016, the Company repurchased $1.8 billion, or 35 million shares, and $778 million, or 30 million shares, respectively.

NOTE 2. Earnings Per Share, continued

Management's assessment of market conditions and other factors guides the timing and volume of repurchases. Future share repurchases are expected to be funded by cash on hand, cash generated from operations and debt issuances. Shares are retired immediately upon repurchase. In accordance with the Equity Topic in the ASC, the excess of repurchase price over par value is recorded in retained earnings. Generally, retained earnings is only impacted by net earnings and dividends.