Funded Status of Plans (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Pension Plans, Defined Benefit
Defined Benefit Plan, Fair Value of Plan Assets	$ 2,873		$ 2,742		$ 2,550
Defined Benefit Plan, Benefit Obligation	(2,575)	[1]	(2,838)	[1]	(2,661)
Defined Benefit Plan, Funded Status of Plan	298		(96)
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan, Fair Value of Plan Assets	158	[2],[3]	164	[2],[3]	161
Defined Benefit Plan, Benefit Obligation	(81)	[1],[2]	(167)	[1],[2]	(173)
Defined Benefit Plan, Funded Status of Plan	$ 77	[2]	$ (3)	[2]

[1] 1 Includes $80 million and $91 million of benefit obligations for the unfunded nonqualified supplemental pension plans at December 31, 2013 and 2012, respectively.

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

[3] 1 Schedule does not include accrued income.