Equity (Stock Repurchase Program) (Details) (USD $)	0 Months Ended	3 Months Ended		12 Months Ended			0 Months Ended	2 Months Ended	12 Months Ended			2 Months Ended	12 Months Ended
	Jun. 26, 2009	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 30, 2012 Warrants Issued to Allianz [Member]	Feb. 25, 2014 Common Stock [Member]	Dec. 31, 2013 Common Stock [Member]	Dec. 31, 2012 Common Stock [Member]	Dec. 31, 2011 Common Stock [Member]	Feb. 25, 2014 Treasury Stock [Member]	Dec. 31, 2013 Treasury Stock [Member]	Dec. 31, 2012 Treasury Stock [Member]	Dec. 31, 2011 Treasury Stock [Member]	Dec. 31, 2013 Additional Paid-in Capital [Member]	Dec. 31, 2012 Additional Paid-in Capital [Member]	Dec. 31, 2011 Additional Paid-in Capital [Member]
Class of Stock [Line Items]
Stock Issued During Period, Shares, Warrant Exercised									13,497,000	0	0
Warrants, acquired																1,600,000
Payments for Repurchase of Warrants				$ 33,000,000	$ 300,000,000											$ 33,000,000	$ (300,000,000)
Authorization of stock repurchase program				500,000,000
Treasury stock acquired				8,000,000				7,700,000	19,235,000	8,045,000	3,225,000
Common stock repurchased, value				149,000,000								262,000,000	600,000,000	149,000,000	51,000,000
Repurchase of warrants							300,000,000											0
Warrants to purchase shares							69,351,806
Exercise price of warrant							$ 25.23
Stock Repurchase Program, Authorized Amount	750,000,000	2,000,000,000	500,000,000	1,250,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount				$ 600,000,000