Income Taxes Income Taxes - Effective Income Tax Rate Table (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Income tax expense (benefit) at the federal statutory rate (35%)	$ 505	$ (341)	$ 1,008
State income taxes (net of federal income tax benefit)	38	(38)	74
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	5	(1)	41
Total Income Tax Expense (Benefit)	$ 548	$ (380)	$ 1,123