CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
ASSETS:
Securities held-to-maturity, fair value	$ 4,995	$ 5,058
STOCKHOLDERS’ EQUITY:
Preferred stock, par value (in dollars per share)	$ 25.00	$ 25.00
Preferred stock, authorized (in shares)	100,000,000	100,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, issued (in shares)	565,589,795	564,630,542
Common stock, outstanding (in shares)	509,515,646	511,954,871
Treasury stock (in shares)	56,074,149	52,675,671
Series A Preferred Stock
STOCKHOLDERS’ EQUITY:
Preferred stock, par value (in dollars per share)	$ 25.00	$ 25.00
Preferred stock, authorized (in shares)	250,000	250,000
Preferred stock, issued (in shares)	250,000	250,000
Preferred stock, liquidation preference (in dollars per share)	$ 1,000	$ 1,000
Available-for-sale Securities
ASSETS:
Securities, pledged as collateral	$ 243	$ 256