Shareholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified			12 Months Ended			12 Months Ended			0 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Common stock	Dec. 31, 2013 Preferred stock purchase rights	Dec. 31, 2013 Preferred stock purchase rights Newly created series of preferred stock	Dec. 31, 2013 Preferred stock purchase rights Common stock item	Nov. 19, 2012 Stock buyback program 2000	Dec. 31, 2000 Stock buyback program 2000	Sep. 30, 2013 Accelerated Share Repurchase program 2012	Nov. 20, 2012 Accelerated Share Repurchase program 2012	Dec. 31, 2013 Accelerated Share Repurchase program 2012	Dec. 31, 2012 Accelerated Share Repurchase program 2012	Dec. 31, 2013 Share repurchase program addition December 2013	Dec. 31, 2013 Share repurchase program addition December 2013
Shareholders' Equity
Maximum number of shares authorized for purchases under the program								500,000
Total shares purchased	6,242,326	6,415,176					11,300
Purchase price of stock repurchased recorded as a reduction in stockholder's equity										$ 50
Available value of shares authorized for repurchase under the Program													$ 150
Shares repurchased										3,276,002		3,276,002		146,800
Shares sold back			340,334						340,334		340,334
Average purchase price (in dollars per share)												$ 15.26		$ 20.37
Number of preferred share purchase rights held by shareholders for each share of common stock owned				1
Number of shares of preferred stock that a holder is entitled to purchase					0.0001
Purchase price per unit (in dollars per share)					$ 35
Minimum beneficial ownership percentage required to exercise the rights				10.00%
Minimum beneficial ownership percentage of certain institutional investors for exercise of rights				15.00%
Value of stock called by rights as multiple of exercise price of rights						2