Stockholders' Equity Stockholders' Equity, Share Repurchases and Dividends (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended						9 Months Ended		0 Months Ended	9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2014	Sep. 30, 2013	Oct. 30, 2014 Subsequent Event	Sep. 30, 2014 2013 Share repurchase program	Sep. 30, 2013 2013 Share repurchase program	Nov. 06, 2013 2013 Share repurchase program	Jul. 30, 2014 2014 Share repurchase program
Number of shares purchased (shares)										6.2	6.4
Share repurchases, value										$ 350,000,000	$ 336,000,000
Stock Repurchase Program, Authorized Amount												1,000,000,000	1,000,000,000
Dividend payments	$ 39,000,000			$ 33,000,000			$ 104,000,000	$ 88,000,000
Dividends declared (dollars per share)	$ 0.30	$ 0.25	$ 0.25	$ 0.25	$ 0.20	$ 0.20	$ 0.80	$ 0.65	$ 0.30
Dividends payable, date declared									Oct. 30, 2014
Dividends, date to be paid									Dec. 15, 2014
Dividends, date of record									Nov. 28, 2014