Income Taxes (Reconciliation Of Effective Tax Rate) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Tax computed at statutory rate	$ 975,798	$ 574,682	$ 67,327
State income taxes, net of federal tax benefit	110,739	64,284	4,372
Domestic production activities deduction	(54,745)	(32,194)	(940)
Noncontrolling interest in net income	(12,783)	(14,221)	(11,315)
Uncertain tax positions	7,309	(12,125)	0
Other	1,644	1,565	(132)
Total	$ 1,027,962	$ 581,991	$ 59,312