Income Taxes (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2010	Sep. 30, 2009 M	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes
Income tax receivables, long-term portion		$ 69,000,000	$ 68,633,000	$ 65,103,000
Period over which the cash refunds are not expected to be received (in months)		12
Settlements with taxing authorities	62,000,000		124,000	62,199,000	4,089,000
Net decrease in uncertain tax positions which decreased our effective tax rate	3,000,000
Net interest benefits through the effective tax rate	4,000,000
Tabular reconciliation of the total amounts of unrecognized tax benefits, excluding interest and penalties, at the beginning and end of the year
Total unrecognized tax benefits at the beginning of the year	201,216,000		127,595,000	201,216,000	63,318,000
Additions for tax positions of the current year			10,915,000	7,551,000	44,094,000
Additions for tax positions of prior years					98,942,000
Reductions for tax positions of prior years for:
Changes in judgment			(1,555,000)	(11,017,000)
Settlements with taxing authorities	(62,000,000)		(124,000)	(62,199,000)	(4,089,000)
Lapses of applicable statute of limitations			(826,000)	(7,956,000)	(1,049,000)
Total unrecognized tax benefits at the end of the year			136,005,000	127,595,000	201,216,000
Unrecognized tax benefits if recognized, would decrease effective tax rate			8,000,000	7,000,000	16,000,000
Pre-tax interest expense (benefit) related to unrecognized tax benefits			3,000,000	(2,000,000)	2,000,000
Accrued liabilities for interest related to unrecognized tax benefits			9,000,000	6,000,000	8,000,000
Interest income to be received on the overpayment of income taxes for certain adjustments that we have filed, or will file, with the IRS			$ 4,000,000