Income Taxes - Provision for Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 268	$ 240	$ 354
State	72	38	99
Foreign	36	35	22
Current total	376	313	475
Deferred:
Federal	48	162	85
State	17	36	64
Foreign	2		5
Deferred total	67	198	154
Provision for income taxes	$ 443	$ 511	$ 629