Estimated Amount to be Recognized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Pension Benefits
Schedule Of Accumulated Benefit Obligations In Excess Of Fair Value Of Plan Assets And Amounts Recognized In Balance Sheet And In Other Comprehensive Income Loss [Line Items]
Amortization of actuarial (gain) loss	$ 9
Amortization of prior service cost	3
Total estimated amounts to be recognized	12
Other Postretirement Benefits
Schedule Of Accumulated Benefit Obligations In Excess Of Fair Value Of Plan Assets And Amounts Recognized In Balance Sheet And In Other Comprehensive Income Loss [Line Items]
Amortization of actuarial (gain) loss	(1)
Total estimated amounts to be recognized	$ (1)