Consolidated Balance Sheet (Unaudited) (Parenthetical) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheet [Abstract]
Securities held to maturity, fair value	$ 2,200,000,000	$ 2,300,000,000
Loans held for sale, designated under fair value option	410,000,000	377,000,000
Interest bearing, designated under fair value option	10,000,000,000	9,800,000,000
Long-term debt, designated under fair value option	$ 6,000,000,000	$ 5,000,000,000
Common stock, par value	$ 5	$ 5
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares outstanding	712	712
Common stock, shares issued	712	712