Change in Plan Assets (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Pension Plans, Defined Benefit
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,742		$ 2,550
Defined Benefit Plan, Actual Return on Plan Assets	304		350
Defined Benefit Plan, Contributions by Employer	8		26
Defined Benefit Plan, Contributions by Plan Participants	0		0
Defined Benefit Plan, Benefits Paid	(181)		(184)
Defined Benefit Plan, Fair Value of Plan Assets	2,873		2,742
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan, Fair Value of Plan Assets	164	[1],[2]	161
Defined Benefit Plan, Actual Return on Plan Assets	14		17
Defined Benefit Plan, Contributions by Employer	0		0
Defined Benefit Plan, Contributions by Plan Participants	21		22
Defined Benefit Plan, Benefits Paid	(41)		(36)
Defined Benefit Plan, Fair Value of Plan Assets	$ 158	[1],[2]	$ 164	[1],[2]

[1] 2 Plan remeasured at December 31, 2013 due to plan amendment.

[2] 1 Schedule does not include accrued income.