Income Taxes Level 4 (Details) - Summary of the Valuation Allowance (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Valuation Allowance [Line Items]      
Income Tax Expense (Benefit) $ 26 $ 349 $ (384)
Deferred Tax Assets, Operating Loss Carryforwards, Domestic 999    
Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Period 518 122 432
Changes in Related Gross Deferred Tax Assets/Liabilities 24 (58) 11
Charge/Release 46 454 (321)
Balance at End of Period 588 518 122
Tax Credit Carryforward, Amount 2    
Valuation allowance on state net operating loss carryforwards 63    
Operating Loss Carryforwards, Valuation Allowance 154    
Undistributed Earnings of Foreign Subsidiaries $ 433