Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Contingency [Line Items]
Income tax expense associated with an indemnification benefit from income tax claim related to acquisition	$ 40,000,000	$ 55,000,000
Income tax expense (benefit) related to net gains (losses) from sales of investment securities	22,000,000	55,000,000	(98,000,000)
Income (loss) from continuing operations before income taxes, foreign	1,110,000,000	1,230,000,000	1,340,000,000
Investment of retained earnings	2,700,000,000
Deferred tax assets, operating loss carryforwards	45,000,000	34,000,000
Tax Credit Carryforward, Deferred Tax Asset	76,000,000	34,000,000
Tax Credit Carryforward, Expiration Date	Dec. 31, 2032
Tax positions for which the ultimate deductibility is highly certain but time is uncertain	35,000,000
Interest accrued	2,000,000	8,000,000
Interest expense	$ 12,000,000	$ 10,000,000
Minimum [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards expiration dates	2013
Maximum [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards expiration dates	2031