Income Taxes (Details 5) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2015
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	$ 61	$ 1	$ 1
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	75
Estimated value of uncertain tax positions - accrued interest and penalties	25
Federal and foreign income tax benefits that would impact the rate	145
Operating Loss Carryforwards	211
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal income tax statutory rate	35.00%
Deferred Tax Assets, Gross [Abstract]
Valuation allowance against tax assets	53	55
Maximum | Forecast
Income Tax Contingency [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions				(40)
Partial resolution of IRS examination of the company's 2007-2009 tax returns [Member]
Income Tax Contingency [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	(51)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	59
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ (12)