CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Common shares, par value	$ 0.10	$ 0.10
Common shares, shares authorized	600,000,000	600,000,000
Common shares, shares issued	359,469,367	359,378,751
Treasury at cost	1,010,390	1,030,053
Class H Preferred Shares [Member]
Cumulative redeemable preferred shares, liquidation value	$ 500	$ 500
Cumulative redeemable preferred shares, shares authorized	750,000	750,000
Cumulative redeemable preferred shares, shares issued	110,000	110,000
Cumulative redeemable preferred shares, shares outstanding	110,000	110,000
Preferred stock dividend rate	7.375%	7.375%
Cumulative redeemable preferred shares, par value
Class J Preferred Shares [Member]
Cumulative redeemable preferred shares, liquidation value	$ 500	$ 500
Cumulative redeemable preferred shares, shares authorized	750,000	750,000
Cumulative redeemable preferred shares, shares issued	400,000	400,000
Cumulative redeemable preferred shares, shares outstanding	400,000	400,000
Preferred stock dividend rate	6.50%	6.50%
Cumulative redeemable preferred shares, par value
Class K Preferred Shares [Member]
Cumulative redeemable preferred shares, liquidation value	$ 500	$ 500
Cumulative redeemable preferred shares, shares authorized	750,000	750,000
Cumulative redeemable preferred shares, shares issued	300,000	300,000
Cumulative redeemable preferred shares, shares outstanding	300,000	300,000
Preferred stock dividend rate	6.25%	6.25%
Cumulative redeemable preferred shares, par value