Income per Share Income per Share (Tables)

12 Months Ended

Dec. 31, 2015

Weighted average shares outstanding and antidilutive shares [Line Items]

Weighted average shares outstanding and antidilutive shares [Table Text Block]

A reconciliation of the number of shares used for the basic and diluted income per share computations is as follows:

	Year Ended December 31
Millions of shares	2015	2014	2013
Basic weighted average common shares outstanding	853	848	898
Dilutive effect of awards granted under our stock incentive plans	—	4	4
Diluted weighted average common shares outstanding	853	852	902
Antidilutive shares:
Options with exercise price greater than the average market price	10	2	3
Options which ordinarily would be considered dilutive if not for being in net loss position	2	—	—
Total antidilutive shares	12	2	3