EPS under Basic and Diluted Computations (Parenthetical) (Detail) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Earnings Per Share Disclosure [Line Items]
Antidilutive stock options and restricted stock awards excluded from the calculation of diluted EPS	74	63	52

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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+ Details