Expected Cash Flows for the Pension Benefit and Other Postretirement Benefit Plans (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Pension Plans, Defined Benefit
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	$ 171,000,000	[1],[2]
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	153,000,000	[1],[2]
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	153,000,000	[1],[2]
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	155,000,000	[1],[2]
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	155,000,000	[1],[2]
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	817,000,000	[1],[2]
Pension Plans, Defined Benefit | Plan Participants
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	7,000,000	[1],[2]
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	12,000,000	[3]
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	9,000,000	[3]
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	8,000,000	[3]
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	8,000,000	[3]
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	7,000,000	[3]
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	25,000,000	[3]
Other Postretirement Benefit Plans, Defined Benefit | Plan Participants
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	0	[3]
Medicare Part D
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	(1,000,000)
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	0
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	0
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	0
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	0
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	0
Medicare Part D | Plan Participants
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ (1,000,000)

[1] 1 At this time, the Company anticipates contributions to the Retirement Plan will be permitted (but not required) during 2014 based on the funded status and contribution limitations under the ERISA.

[2] 2 The expected benefit payments for the SERP will be paid directly from the Company's corporate assets.

[3] 3 Expected benefit payments under Other Postretirement Benefits Plans are shown net of participant contributions.