Consolidated Balance Sheet (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Consolidated Balance Sheet [Abstract]
Pledged securities that can be sold or repledged	$ 1,826,011	$ 1,937,817
Investment securities, available for sale, amortized cost	6,312,423	5,494,377
Investment securities, held to maturity, fair value	1,012,562	1,225,253
Other debt securities, fair value	$ 366,886	$ 412,709
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	381,500	778,000
Preferred stock, shares outstanding	50,000	0
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Liquidation preference, per share	$ 10,000	$ 10,000
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	125,683,398	120,396,611
Common stock issuable, shares	68,220	71,345
Treasury stock - common, shares	0	693,974