Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal	$ 1,067	$ 1,006	$ 595
States and Puerto Rico	90	81	53
Total current provision	1,157	1,087	648
Deferred (benefit) provision	(2)	(64)	42
Provision for income taxes	$ 1,155	$ 1,023	$ 690