Income per Share (Tables)

9 Months Ended

Sep. 30, 2012

Earnings Per Share [Abstract]

Reconciliation of the number of shares used for the basic and diluted income per share calculations

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

	Three Months Ended September 30		Nine Months Ended September 30
Millions of shares	2012	2011	2012	2011
Basic weighted average common shares outstanding	928	920	925	917
Dilutive effect of employee stock plans	2	5	2	5
Diluted weighted average common shares outstanding	930	925	927	922