Income Taxes (Provision (Benefit) for Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Income Taxes
Federal Current	$ 3,378		$ 10,421		$ (65,309)
State Current	820		1,518		340
Total Current	4,198		11,939		(64,969)
Federal Deferred	345,922		319,279		48,308
State Deferred	60,941		59,982		298
Foreign Deferred	2,160		459		0
Deferred	409,023		379,720		48,606
Provision (benefit) for income taxes	$ 413,221	[1]	$ 391,659	[1]	$ (16,363)

[1] (1) Interest income, interest expense and the provision (benefit) for income taxes by segment are an allocation of corporate amounts as cash equivalents, debt and income tax expense allocated as they are incurred at the corporate level.