Accounting Policies Calculation of Diluted Shares (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Shares used in computation of basic earnings per share	468	463	467	461
Total dilutive effect of outstanding stock awards	10	0	9	0
Shares used in computation of diluted earnings per share	478	463	476	461