Net Funded Status (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prepaid benefit cost		$ 4
Accrued benefit liability	(72)	(34)
Net underfunded status	$ (72)	$ (30)

This represents the entire assets recognized in the balance sheet that are associated with the defined benefit plans.

This represents the entire liability recognized in the balance sheet that is associated with the defined benefit plans.

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+ Details