Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2009	Dec. 31, 2011	Dec. 31, 2010
Valuation Allowance [Line Items]
Future Tax Expense (Benefit)	$ 321,000,000
Valuation Allowance, Amount	11,000,000,000
Non Cash Income Tax Expense Recorded In Other Comprehensive Income		(321,000,000)
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	402,000,000		402,000,000
Operating Loss Carryforwards	16,300,000,000
Operating Loss Carryforwards, Expiration Dates	2022
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	12,000,000		5,000,000	72,000,000
Accumulated Other Comprehensive Income Valuation Allowance Net Of Tax	$ (3,144,000,000)	$ (1,207,000,000)	$ (2,454,000,000)	$ (1,213,000,000)