STOCKHOLDERS' EQUITY - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Class Of Stock [Line Items]
Common stock, shares authorized		2,000,000,000	2,000,000,000
Common stock, shares issued		216,051,128	213,724,749
Common stock, shares outstanding		215,088,698	212,984,700
Granted shares of restricted stock		1,013,495
Percentage of restricted stock lapse		50.00%
Remaining percentage of share vest during period		50.00%
Corporation has authorized shares of preferred stock		50,000,000	50,000,000
Preferred stock, par value		$ 1.00
Liquidation value per share		$ 25
Repurchased of common stock		222,381	173,870
Stock repurchase plan treasury stock		962,430	740,049
Conversion Of Stock Shares Issued	852,831		4,597,121
Shares Of Preferred Stock Exchanged			1,077,726
Legal Surplus Amount Additions		$ 2.8
Minimum [Member]
Class Of Stock [Line Items]
Legal surplus reserve rate		10.00%
Restricted Stock [Member]
Class Of Stock [Line Items]
Repurchased of common stock		72,918	68,870
Forefeited		(23,000)
Number of vested shares		(349,190)
7.125% Noncumulative Perpetual Monthly Income Preferred Stock, Series A [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage		7.125%
8.35% Noncumulative Perpetual Monthly Income Preferred Stock, Series B [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage		8.35%
7.40% Noncumulative Perpetual Monthly Income Preferred Stock, Series C [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage		7.40%
7.25% Noncumulative Perpetual Monthly Income Preferred Stock, Series D [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage		7.25%
7.00% Noncumulative Perpetual Monthly Income Preferred Stock, Series E [Member]
Class Of Stock [Line Items]
Preferred stock dividend rate percentage		7.00%