Earnings Per Share

Basic earnings per share (EPS) is calculated using the weighted average number of common shares outstanding during the period and includes the effect of any participating securities as appropriate. Participating securities consist of unvested restricted stock issued to our employees and non-employee directors that provide dividend rights.

Diluted EPS is calculated assuming the issuance of common shares for all potentially dilutive securities, provided the effect is not antidilutive. For the Current Quarter, the Prior Quarter, the Current Period and the Prior Period, our contingent convertible senior notes did not have a dilutive effect and therefore were excluded from the calculation of diluted EPS. See Note 3 for further discussion of our convertible senior notes and contingent convertible senior notes.

For the Current Quarter, the Prior Quarter, the Current Period and the Prior Period, shares of common stock for the following dilutive securities were excluded from the calculation of diluted EPS as the effect was antidilutive.



		Shares
		(in millions)
Three Months Ended June 30, 2017
Participating securities		1
Three Months Ended June 30, 2016
Common stock equivalent of our preferred stock outstanding:
5.75% cumulative convertible preferred stock		58
5.75% cumulative convertible preferred stock (series A)		42
5.00% cumulative convertible preferred stock (series 2005B)		6
4.50% cumulative convertible preferred stock		6
Participating securities		1
Six Months Ended June 30, 2017
Common stock equivalent of our preferred stock outstanding:
5.75% cumulative convertible preferred stock		31
5.75% cumulative convertible preferred stock (series A)		18
5.00% cumulative convertible preferred stock (series 2005B)		5
4.50% cumulative convertible preferred stock		6
Participating securities		1
Common stock equivalent of our preferred stock outstanding prior to exchange:
5.75% cumulative convertible preferred stock exchanged		1
Six Months Ended June 30, 2016
Common stock equivalent of our preferred stock outstanding:
5.75% cumulative convertible preferred stock		58
5.75% cumulative convertible preferred stock (series A)		42
5.00% cumulative convertible preferred stock (series 2005B)		6
4.50% cumulative convertible preferred stock		6
Participating securities		1

For the Current Quarter and the Current Period, outstanding stock options were included in the calculation of diluted EPS. A reconciliation of basic EPS and diluted EPS is as follows:



	Income (Numerator)		Weighted Average Shares (Denominator)	Per Share Amount
	(in millions, except per share data)
Three Months Ended June 30, 2017
Basic EPS	$	470	908	$	0.52
Effect of Dilutive Securities:
5.75% cumulative convertible preferred stock	11		31
5.75% cumulative convertible preferred stock (series A)	7		18
5.00% cumulative convertible preferred stock (series 2005B)	2		5
4.50% cumulative convertible preferred stock	3		6
5.5% convertible senior notes due 2026	36		146
Diluted EPS	$	529	1,114	$	0.47

Six Months Ended June 30, 2017
Basic EPS	$	547	907	$	0.60
Effect of Dilutive Securities:
5.5% convertible senior notes due 2026	72		146
Diluted EPS	$	619	1,053	$	0.59