Investments (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Apr. 03, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Available-for-sale Debt Securities, Gross Unrealized Loss $ 101  
Trading Securities    
Trading Securities Unrealized Holding Gains (Losses) 40 43
Marketable Securities 315 255
Other Assets 94 96
Equity Securities [Member]    
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Total trading securities $ 409 $ 351