Income Taxes (Details 5) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred Tax Liabilities and Assets Not Recognized [Line Items]
Effective tax rate on income from continuing operations	33.30%	32.30%	19.50%
Recognition of net tax benefits, as a result of the settlement			$ 298
Estimated value of uncertain tax positions - accrued interest and penalties	19
Federal and foreign income tax benefits that would impact the rate	128
Net interest income (expense) included in federal and foreign, and state income tax provisions	(1)	(5)	88
Valuation allowance against tax assets	52	50
Federal income tax statutory rate	35.00%
United Kingdom
Deferred Tax Liabilities and Assets Not Recognized [Line Items]
Unused net operating losses	$ 185