Share Repurchases in the Open Market (Detail) - Jun. 30, 2015 - USD ($) $ / shares in Units, shares in Millions, $ in Millions		Total	Total
Stockholders' Equity Note [Abstract]
Shares repurchased in the open market	[1]	15	44
Average repurchase price per share	[2]	$ 68.05	$ 65.98
Total cost		$ 1,055	$ 2,910

[1] All shares repurchased in the open market have been retired and constitute authorized but unissued shares.

[2] Figures in the table may not recalculate exactly due to rounding. Average repurchase price per share is calculated based on unrounded numbers.