Stockholders' Equity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stockholders' Equity Attributable to Parent [Abstract]
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Common Stock, Shares Authorized	2,000,000,000	2,000,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Treasury Stock, Shares	248,000,000	238,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 535,000,000
Stock Repurchase Program, Authorized Amount		1,000,000,000
Stock Repurchased During Period, Shares	10,000,000	51,000,000	105,000,000
Payments for Repurchase of Common Stock	$ 125,000,000	$ 500,000,000	$ 600,000,000