Estimated Amounts to be Amortized from AOCI into Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Total	$ 24

- Definition

The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.

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