Equity (Narrative) (Details) (USD $)	0 Months Ended		12 Months Ended		0 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended	0 Months Ended	1 Months Ended
	Nov. 07, 2012	Mar. 28, 2012	Dec. 31, 2012	Nov. 30, 2011	Mar. 05, 2011 Restricted Stock Units (RSUs) [Member]	Mar. 05, 2010 Restricted Stock Units (RSUs) [Member]	Mar. 05, 2009 Restricted Stock Units (RSUs) [Member]	Jun. 30, 2013 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2013 Restricted Stock Units (RSUs) [Member]	Jun. 30, 2013 Restricted Stock Units (RSUs) [Member] Special Distribution [Member]	Mar. 28, 2012 Restricted Stock Units (RSUs) [Member] Special Dividend [Member]	Jun. 30, 2013 Restricted Stock Units (RSUs) [Member] Special Dividend [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock, shares issued net of shares for tax withholdings								91,204		41,300		19,368
Shares surrendered to fund withholding taxes, shares								83,796		40,033		18,774
Restricted stock units granted to former Chief Executive Officer					40,000	50,000	85,000
Shares, Vested								175,000	27,681
Dividends per share		$ 13.60
Common dividends declared ($13.60 per share)		$ 417,600,000	$ 417,606,000
Dividends payable date		Apr. 20, 2012
Dividend payable record date		Apr. 10, 2012
Equitable adjustment to stock options outstanding											19,058
Equitable adjustment to restricted stock units for dividends and distributions										5,100,000		2,400,000
Special distribution Paid date	Dec. 04, 2012
Special distribution record date	Nov. 19, 2012
Special distribution declared per share	$ 29.00		$ 29.00
Equitable adjustment to restricted stock units outstanding											6,875
Aggregate special distribution	$ 892,100,000
Voting common stock repurchased, authorized shares				800,000