Equity (Details) (USD $)	3 Months Ended	12 Months Ended			134 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Treasury Stock, Shares, Acquired	246,104				36,186,389
Treasury Stock, Value, Acquired, Cost Method	$ 45,200,000				$ 1,200,000,000
Treasury Stock Acquired, Average Cost Per Share					$ 32.91
Treasury Stock, Shares, Retired		1,149,582			29,825,406
Treasury Stock, Retired, Cost Method, Amount		0	0	0	680,200,000
Treasury Stock, Shares		1,648,613	1,550,173		1,648,613
Treasury shares, Remaining shares authorized to be purchased		3,026,387			3,026,387
Common Stock, Dividends, Per Share, Cash Paid		$ 0.32
Dividends		$ (58,642,000)	$ (52,950,000)	$ (46,027,000)
Common Stock, Dividends, Per Share, Declared	$ 0.50