Subsequent Events (Narrative) (Details) (USD $)	0 Months Ended		1 Months Ended
	Apr. 17, 2012	Mar. 31, 2012	Apr. 17, 2012 Series C Preferred Stock [Member]	Apr. 30, 2012 Series F Preferred Stock [Member]
Subsequent Event [Line Items]
Preferred stock, issued				7,300,000
Preferred stock, dividend rate			4.375%	6.625%
Preferred unit offering costs				$ 175,800,000
Senior unsecured multi-currency term loan	$ 750.0
Revolving credit facility, maturity date	Apr. 16, 2017
Senior unsecured loan, spread on variable rate		1.45%
Preferred Stock conversion ratio			0.5480