Subsequent Events (Tables)

3 Months Ended

Mar. 31, 2013

Subsequent Events [Abstract]

Schedule of Dividends Declared

Class of stock/units	Quarterly Amount per Share or Unit	Record Date	Payment Date
Common	$0.17	May 16, 2013	May 31, 2013
Preferred (per depositary share or unit):
Series J	$0.414063	May 16, 2013	May 31, 2013
Series K	$0.406250	May 16, 2013	May 31, 2013
Series L	$0.412500	May 16, 2013	May 31, 2013