CONSOLIDATED BALANCE SHEET (UNAUDITED) (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Securities held-to-maturity, fair value	$ 1,598,000,000	$ 1,831,000,000
Loans held for sale, fair value	1,000,000	465,000,000
Interest bearing, designated under fair value option	7,900,000,000	8,700,000,000
Long-term debt, designated under fair value option	$ 6,800,000,000	$ 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