Stock-Based Compensation Expense Recognized in Noninterest Expense (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock-based compensation expense:
Stock options	$ 0	$ 0	$ 0	$ 1
Restricted Stock Expense	4	6	9	14
Phantom stock expense	9	4	17	6
Restricted stock units	10	7	28	21
Total stock-based compensation expense	23	17	54	42
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	$ 9	$ 6	$ 21	$ 16