Stockholders Equity (Details) (USD $) Share data in Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method	$ 1,015,000,000	$ 513,000,000	$ 8,000,000
Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	1,500,000,000
Authorized Stock Repurchase Program Repurchase Amount	4,700,000,000
Authorized Stock Repurchase Program Repurchased Number Of Shares	121
Treasury Stock, Value, Acquired, Cost Method	$ 1,000,000,000
Treasury Stock, Shares, Acquired	29