Activity Related to Noncontrolling Interests (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 80	$ 73
Acquired noncontrolling interests	(67)	7
Dividends attributable to noncontrolling interests	0	0
Net income attributable to noncontrolling interests	0	0
Balance at end of period	$ 13	$ 80

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest).

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Represents an increase in noncontrolling interest from issuance of additional equity interests to noncontrolling interest holders or the sale of a portion of the parent's controlling interest.

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- Definition

Amount of Net Income (Loss) attributable to noncontrolling interest.

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- Definition

Cash outflow in the form of ordinary dividends to noncontrolling interests, generally out of earnings.

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