Net Periodic Benefit Cost and Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Pension And Other Postretirment Benefits Recgonized In Accumulated Other Comprehensive Income (Loss) [Abstract]
Interest cost	$ 10	$ 10	$ 11
Expected return on assets	(13)	(13)	(15)
Amortization of net actuarial loss	11	14	11
Amortization of net prior service cost			1
Settlement	5	6	6
Net periodic pension cost	13	17	14
Net actuarial gain (loss) arising during the period	(38)	7	50
Amortization of net actuarial loss	(11)	(14)	(11)
Amortization of prior service cost			(1)
Settlement	(5)	(6)	(6)
Total recognized in other comprehensive income	(54)	(13)	32
Total recognized in net periodic benefit cost and other comprehensive income	$ (41)	$ 4	$ 46