Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Current Income Tax Expense (Benefit)	$ 1	$ 83	$ (7)
Deferred Other Tax Expense (Benefit)	(449)	(349)	(265)
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance	432	351	257
Income Tax Expense (Benefit)	$ (16)	$ 85	$ (15)