Restructuring Level 4 (Details) - Restructuring by Type (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]    
Cumulative restructuring costs, Incurred to Date $ 13  
Restructuring Reserve [Roll Forward]    
Accrued liability, Beginning Balance 0  
Restructuring charges 13 13
Payments   (1)
Accrued liability, Ending Balance 12 0
Workforce reductions [Member]    
Restructuring Cost and Reserve [Line Items]    
Restructuring costs expected to be incurred 19  
Cumulative restructuring costs, Incurred to Date 13  
Restructuring Reserve [Roll Forward]    
Accrued liability, Beginning Balance   0
Restructuring charges   13
Payments   (1)
Accrued liability, Ending Balance   $ 12