Earnings (Losses) per Share - Reconciliation of Basic Earnings Per Share to Diluted Earnings Per Share for Income from Continuing Operations (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Income from continuing operations	$ 137	$ 129	$ 280	$ 258
Weighted average common shares for basic earnings per share	192	195	192	193
Effect of dilutive stock options and restricted stock awards	2	3	2	4
Weighted average common shares for diluted earnings per share	194	198	194	197
Basic earnings per share	$ 0.72	$ 0.67	$ 1.46	$ 1.34
Diluted earnings per share	$ 0.71	$ 0.66	$ 1.44	$ 1.31