Aggregate dividends paid during the period for each share of common stock outstanding.

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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

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Current fair value of each cash settlement alternative for each freestanding forward contract.

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Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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Amount of a stock repurchase plan authorized by an entity's Board of Directors.

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No definition available.

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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Capital Stock, Dividends and Share Repurchases - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended			3 Months Ended	1 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Feb. 28, 2015
Stock Repurchase Program [Line Items]
Common stock shares authorized	1,500,000,000us-gaap_CommonStockSharesAuthorized	1,500,000,000us-gaap_CommonStockSharesAuthorized	1,500,000,000us-gaap_CommonStockSharesAuthorized
Common stock par value per share	$ 0.01	$ 0.01	$ 0.01
Common stock shares issued	630,282,461us-gaap_CommonStockSharesIssued	630,282,461us-gaap_CommonStockSharesIssued	630,282,461us-gaap_CommonStockSharesIssued
Common stock shares outstanding	458,500,000us-gaap_CommonStockSharesOutstanding	458,500,000us-gaap_CommonStockSharesOutstanding	464,300,000us-gaap_CommonStockSharesOutstanding	464,200,000us-gaap_CommonStockSharesOutstanding
Preferred stock shares authorized	10,000,000us-gaap_PreferredStockSharesAuthorized	10,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock par value per share	$ 0.01	$ 0.01
Preferred stock shares outstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding
Cash dividends		$ 693us-gaap_PaymentsOfDividendsCommonStock	$ 683us-gaap_PaymentsOfDividendsCommonStock	$ 658us-gaap_PaymentsOfDividendsCommonStock
Cash dividends declared and paid per common share	$ 0.375	$ 1.50	$ 1.46	$ 1.42
Treasury stock at cost		600	239
Accelerated Share Repurchase Agreement (ASR) [Member]
Stock Repurchase Program [Line Items]
Treasury stock at cost					420
Forward contract indexed to own stock					180
Share Repurchase Program [Member] \| Subsequent Event [Member]
Stock Repurchase Program [Line Items]
Maximum capital allocated for repurchases of shares						$ 1,000