Stock-Based Compensation Expense Recognized in Noninterest Expense (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Stock-based compensation expense:
Stock options	$ 0	$ 0	$ 1	$ 1
Restricted Stock Expense	4	7	13	21
Phantom stock expense	5	4	21	9
Restricted stock units	7	5	35	27
Total stock-based compensation expense	16	16	70	58
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	$ 6	$ 6	$ 27	$ 22