Debt 7.75% Senior Subordinated Notes (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Long-term Debt, Gross	$ 2,346,488,000	$ 2,500,434,000
Debt Instrument, Repurchased Face Amount		150,000,000
Gains (Losses) on Extinguishment of Debt	69,381,000	56,280,000	47,558,000
Current Fiscal Year End Date	--12-31
7.75% Senior Subordinated Notes, Due 2020 [Member]
Long-term Debt, Gross	0	400,000,000
Debt Instrument, Interest Rate, Stated Percentage	7.75%
Debt Instrument, Repurchased Face Amount	400,000,000
Cash Paid for Debt Repurchased	429,000,000
Gains (Losses) on Extinguishment of Debt	29,000,000	19,000,000
Deferred Finance Costs, Gross	13,000,000
Amortization of Financing Costs	1,000,000	1,000,000	1,000,000
Write off of Deferred Debt Issuance Cost	5,000,000	2,000,000
Initial 7.75% Swap Agreement [Member]
Gains (Losses) on Extinguishment of Debt	(18,000,000)
Initial 7.75% Swap Agreement [Member] | 7.75% Senior Subordinated Notes, Due 2020 [Member]
Derivative, Basis Spread on Variable Rate	3.87%
Additional 7.75% swap agreement [Member]
Gains (Losses) on Extinguishment of Debt		$ 5,000,000
Additional 7.75% swap agreement [Member] | 7.75% Senior Subordinated Notes, Due 2020 [Member]
Derivative, Basis Spread on Variable Rate	5.32%