CONSOLIDATED BALANCE SHEET (UNAUDITED) (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Securities held-to-maturity, fair value	$ 1,600,000,000	$ 1,800,000,000
Loans held for sale, fair value	3,000,000	465,000,000
Interest bearing, designated under fair value option	8,400,000,000	8,700,000,000
Long-term debt, designated under fair value option	$ 7,700,000,000	$ 7,300,000,000
Common stock, par value (usd per share)	$ 5	$ 5
Common stock, shares authorized (shares)	150,000,000	150,000,000
Common stock, shares issued (shares)	713	713
Common stock, shares outstanding (shares)	713	713