Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jan. 25, 2013
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	248,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 535
Stock Repurchase Program, Authorized Amount				$ 1,000
Stock Repurchased During Period, Shares		10,000,000	51,000,000
Payments for Repurchase of Common Stock	$ 0	$ 125	$ 500