Components of Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Pension Plans, Defined Benefit
Defined Benefit Plan, Service Cost	$ 1	[1]	$ 1	[1]	$ 2	[1]	$ 2	[1]
Defined Benefit Plan, Actuarial Gain (Loss)	4		7		8		13
Defined Benefit Plan, Interest Cost	31		28		62		56
Defined Benefit Plan, Expected Return on Plan Assets	(50)	[1]	(48)	[1]	(100)	[1]	(95)	[1]
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0		0		0		0
Net periodic benefit cost	(14)		(12)		(28)		(24)
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan, Service Cost	0		0		0		0
Defined Benefit Plan, Actuarial Gain (Loss)	0		0		0		0
Defined Benefit Plan, Interest Cost	1		2		2		3
Defined Benefit Plan, Expected Return on Plan Assets	(1)		(2)		(3)		(3)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(2)		0		(3)		0
Net periodic benefit cost	$ (2)		$ 0		$ (4)		$ 0

[1] 1 Administrative fees are recognized in service cost for each of the periods presented. Prior to the second quarter of 2014, administrative fees were recognized in expected return on plan assets.