Preferred Stock Issued and Outstanding (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Class of Stock [Line Items]
Shares Issued and Outstanding	885
Liquidation Preference	$ 885	$ 0
Carrying Value	865
Series A Preferred Stock
Class of Stock [Line Items]
Shares Issued and Outstanding	400
Liquidation Preference Per Share	$ 1,000
Liquidation Preference	400
Carrying Value	394
Series B Preferred Stock
Class of Stock [Line Items]
Shares Issued and Outstanding	485
Liquidation Preference Per Share	$ 1,000
Liquidation Preference	485
Carrying Value	$ 471

The per share liquidation preference (or restrictions) of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share.

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Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.

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