Reconciliation of Benefit Obligations, Plan Assets and Funded Status of Pension and Postretirement Plans (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair value beginning balance	$ 1,078
Fair value ending balance	1,134	1,078
Noncurrent liabilities	(305)	(409)
Total recognized net periodic benefit cost and other comprehensive (income) loss	36	44	28
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation beginning balance	1,265	1,183
Service cost	26	24	18
Interest cost	51	55	56
Actuarial (gain) loss	(98)	66
Benefits paid	(65)	(63)
Benefit obligation ending balance	1,179	1,265	1,183
Fair value beginning balance	1,078	998
Actual return on plan assets	90	112
Employer contributions	31	31
Benefits paid from plan assets	(65)	(63)
Fair value ending balance	1,134	1,078	998
Funded status	(45)	(187)
Noncurrent assets	55
Noncurrent liabilities	(100)	(187)
Net amount recognized	(45)	(187)
Net actuarial (gain) loss	(107)	30
Recognized actuarial gain (loss)	(21)	(22)
Recognized prior service cost	(4)	(4)
Total recognized in other comprehensive (income) loss	(132)	4
Total recognized net periodic benefit cost and other comprehensive (income) loss	(112)	33
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation beginning balance	230	212
Service cost	6	5	4
Interest cost	9	10	10
Plan participants' contributions	5	5
Amendments		2
Actuarial (gain) loss	(19)	12
Benefits paid	(18)	(18)
Other		2
Benefit obligation ending balance	213	230	212
Employer contributions	13	13
Plan participants' contributions	5	5
Benefits paid from plan assets	(18)	(18)
Funded status	(213)	(230)
Current liabilities	(14)	(14)
Noncurrent liabilities	(199)	(216)
Net amount recognized	(213)	(230)
Net actuarial (gain) loss	(19)	12
Recognized actuarial gain (loss)	(1)
Prior service cost		2
Total recognized in other comprehensive (income) loss	(20)	14
Total recognized net periodic benefit cost and other comprehensive (income) loss	$ (4)	$ 28