Income Taxes Components of Income Tax Provision (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components of income tax provision [Line Items]
Current Federal Tax Expense (Benefit)	$ 553	$ (4)	$ 0
Current State and Local Tax Expense (Benefit)	26	0	(14)
Current Income Tax Expense (Benefit)	579	(4)	(14)
Deferred Federal Income Tax Expense (Benefit)	229	81	(177)
Deferred State and Local Income Tax Expense (Benefit)	(35)	2	6
Deferred Income Tax Expense (Benefit)	194	83	(171)
Income Tax Expense (Benefit)	$ 773	$ 79	$ (185)