Equity and Earnings Per Share - Calculations of Earnings Per Share of Common Stock (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]
Net Income from continuing operations	$ 75	$ (111)
Net Income from discontinued operations		(319)
Net Income	$ 75	$ (430)
Average shares outstanding	250	237
Adjustment to shares outstanding	1
Weighted Average Shares Outstanding for Computation of Basic Earnings Per Share of Common Stock	251	237
Net effect of potentially dilutive shares
Weighted Average Shares Outstanding for Computation of Diluted Earnings Per Share of Common Stock	251	237
Basic and Diluted Earnings per Share
Earnings per share of common stock from continuing operations	$ 0.30	$ (0.47)
Earnings per share of common stock from discontinued operations		$ (1.35)
Basic and diluted earnings per share	$ 0.30	$ (1.82)