Consolidated Statements of Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Statement of Other Comprehensive Income [Abstract]
Net income (loss), Before-tax Amount	$ 31,477		$ (59,532)		$ (778,529)
Net income (loss), Tax (expense) Benefit	798,732		(1,312)		(12,328)
Net income (loss), Net of Tax Amount	830,209		(60,844)		(790,857)
Net unrealized gains/losses on cash flow hedges: Before-tax Amount
Net unrealized gains (losses) arising during the period, Before-tax Amount	(1,381)		(11,316)		(20,459)
Valuation allowance for the change in deferred taxes arising from unrealized gains/losses, Before-tax Amount	0	[1]	0	[1]	0	[1]
Net unrealized gains (losses), Before-tax Amount	(1,381)		(11,316)		(20,459)
Net unrealized gains/losses on cash flow hedges: Tax (Expense) Benefit
Net unrealized gains (losses) arising during the period, Tax (Expense) Benefit	532		4,279		7,867
Valuation allowance for the change in deferred taxes arising from unrealized gains/losses, Tax (Expense) Benefit	0	[1]	(4,279)	[1]	(7,858)	[1]
Net unrealized gains (losses), Tax (Expense) Benefit	532		0		9
Net unrealized gains/losses on cash flow hedges: Net of Tax Amount
Net unrealized gains (losses) arising during the period, Net of Tax Amount	(849)		(7,037)		(12,592)
Valuation allowance for the change in deferred taxes arising from unrealized gains/losses, Net of Tax Amount	0	[1]	(4,279)	[1]	(7,858)	[1]
Net unrealized gains (losses), Net of Tax Amount	(849)		(11,316)		(20,450)
Net unrealized gains/losses on investment securities available for sale: Before-tax Amount
Net unrealized gains (losses) arising during the period, Before-tax Amount	12,296		50,258		(9,991)
Reclassification adjustment for (gains) losses realized in net income, Tax (Expense) Benefit	(39,142)		(75,007)		1,271
Valuation allowance for the change in deferred taxes arising from unrealized gains/losses, Before-tax Amount	0	[1]	0	[1]	0	[1]
Net unrealized gains (losses), Before-tax Amount	(26,846)		(24,749)		(8,720)
Net unrealized gains/losses on investment securities available for sale: Tax (Expense) Benefit
Net unrealized gains (losses) arising during the period, Tax (Expense) Benefit	(4,730)		(19,349)		3,889
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	15,070		29,271		(494)
Valuation allowance for the change in deferred taxes arising from unrealized gains/losses, Tax (Expense) Benefit	0	[1]	(9,922)	[1]	(3,393)	[1]
Net unrealized gains (losses), Tax (Expense) Benefit	10,340		0		2
Net unrealized gains/losses on investment securities available for sale: Net of Tax Amount
Net unrealized gains (losses) arising during the period, Net of Tax Amount	7,566		30,909		(6,102)
Reclassification adjustment for (gains) losses realized in net income, Net of Tax Amount	(24,072)		(45,736)		777
Valuation allowance for the change in deferred taxes arising from unrealized gains/losses, Net of Tax Amount	0	[1]	(9,922)	[1]	(3,393)	[1]
Net unrealized gains (losses), Net of Tax Amount	(16,506)		(24,749)		(8,718)
Amortization of post-retirement unfunded health benefit: Before-tax Amount
Amortization arising during the period, Before-tax Amount	590		0		2,470
Amortization of post-retirement unfunded health benefit: Tax (Expense) Benefit
Amortization arising during the period, Tax (Expense) Benefit	(227)		0		(950)
Amortization of post-retirement unfunded health benefit: Net of Tax Amount
Amortization arising during the period, Net of Tax Amount	363		0		1,520
Other comprehensive income (loss), Before-tax Amount	(27,637)		(36,065)		(26,709)
Less: comprehensive loss attributable to non-controlling interest, Before-tax Amount	0		(220)		(179)
Other comprehensive income (loss), Tax (Expense) Benefit	10,645		0		(939)
Less: comprehensive loss attributable to non-controlling interest, Tax (Expense) Benefit	0		0		0
Other comprehensive income (loss), Net of Tax Amount	(16,992)		(36,065)		(27,648)
Less: comprehensive loss attributable to non-controlling interest, Net of Tax Amount	0		(220)		(179)
Comprehensive income (loss), Net of Tax Amount	$ 813,217		$ (96,689)		$ (818,326)

[1] In accordance with ASC 740-20-45-11(b), the deferred tax asset valuation allowance associated with unrealized gains and losses not recognized in income is charged directly to other comprehensive income (loss).