Earnings Per Share - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock outstanding	6,000,000
Number of weighted average outstanding diluted shares	1,238,000,000	1,101,000,000
Number of common stock shares issued in a part of acquisition	90,000,000
Convertible Debt Securities [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares, option exercised		89,000,000
Common stock outstanding		89,000,000
Number of weighted average outstanding shares included in both basic and diluted shares		23,000,000
Common stock outstanding		89,000,000
Number of weighted average outstanding diluted shares		66,000,000
Mandatory Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities	77,000,000
Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities		66,000,000
Shares that would have been included in diluted earnings per share calculation		66,000,000
Stock Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities		18,000,000
Shares that would have been included in diluted earnings per share calculation		10,000,000
Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities		31,000,000
Shares that would have been included in diluted earnings per share calculation		5,000,000
Weighted average exercise price of options	14.79	14.53
Equity Unit Purchase Agreements [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of anti-dilutive securities	13,000,000	10,000,000

Shares that would have been included in diluted earnings per share calculation.

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The weighted average exercise price of stock options whose individual exercise prices were greater than the average market price of an entity's common stock during the period.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Number of shares of equity interests issued or issuable to acquire entity.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Number of share options (or share units) exercised during the current period.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

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