Deferred Tax Assets (Liabilities) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Employee benefits	$ 137	$ 161
Settlement costs	525	511
State and local income taxes	22	18
Litigation and legal	24	6
Inventory	3	4
Other	3	2
Gross deferred tax assets	714	702
Deferred tax liabilities:
Depreciation	(66)	(63)
Federal effect of state deferred taxes	(42)	(34)
Gross deferred tax liabilities	(108)	(97)
Net deferred tax assets	$ 606	$ 605