Income Taxes (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Contingency [Line Items]
Total deferred income tax provision benefit		$ 69,223,000	$ (325,223,000)	$ (192,000)
Provision benefit for decrease increase to deferred tax asset for federal AMT credits			10,100,000
Deferred tax benefit provision in other comprehensive income		39,400,000	22,300,000
Excess tax benefit from equity compensation recorded to paid-in-capital		1,200,000	400,000
No longer subject to examination for years prior to		2007
Statute of limitations to expire during next twelve months		2007 and 2008
Liability for UTPs	122,800,000	139,900,000	122,800,000
Unrecognized tax benefits, interest on income taxes accrued		29,000,000
Unrecognized tax benefits, income tax penalties accrued		24,500,000
Potential change in unrecognized tax benefits is reasonably possible during next twelve months, amount of unrecorded benefit tax positions		61,000,000
Unrecognized Tax Benefits that Would reduce the income tax provision		108,100,000
Reversal of valuation allowance based upon change in judgment as to realization			335,300,000
Valuation Allowance, Other Deferred Tax Assets, Changes in Amount				(73,700,000)
Valuation allowance	11,228,000	10,887,000	11,228,000	414,000,000
Benefit To Continuing Operations [Member]
Income Tax Contingency [Line Items]
Reversal of valuation allowance based upon change in judgment as to realization	335,500,000
Valuation Allowance, Other Deferred Tax Assets, Changes in Amount		(300,000)	(402,800,000)	(96,600,000)
Accumulated Other Comprehensive Loss [Member]
Income Tax Contingency [Line Items]
Valuation Allowance, Other Deferred Tax Assets, Changes in Amount				7,000,000
Deferred Tax Asset [Member]
Income Tax Contingency [Line Items]
Valuation Allowance, Other Deferred Tax Assets, Changes in Amount				15,900,000
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, limitations on use		32,600,000
Operating loss carryforwards		380,400,000
Operating loss carryforwards, expiration dates		2012 to 2031
State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards		244,000,000
Operating loss carryforwards, expiration dates		2012 to 2031
Research Credit [Member]
Income Tax Contingency [Line Items]
Federal research credits		5,800,000
Research credit carryforwards, expiration dates		2012 to 2031
Other Tax Carryforward, AMT Tax Credits [Member]
Income Tax Contingency [Line Items]
Federal and state AMT credit carryforwards		$ 14,400,000