Income Tax Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current:
Federal	$ 424	$ 326	$ 400
State	52	50	73
Total current	476	376	473
Deferred:
Federal	44	(43)	12
State	8	(8)	4
Total deferred	52	(51)	16
Taxes on income	$ 528	$ 325	$ 489