EARNINGS PER COMMON SHARE AND DIVIDENDS PER SHARE - Dividends Per Share (Details)						2 Months Ended	3 Months Ended
	Nov. 03, 2020 $ / shares	Nov. 03, 2020 $ / shares	Sep. 01, 2020 $ / shares	Jun. 01, 2020 $ / shares	Mar. 01, 2020 $ / shares	Feb. 29, 2020 $ / shares	Aug. 31, 2020 $ / shares	May 31, 2020 $ / shares
Dividends Payable [Line Items]
Common stock, dividends, per share, declared (in dollars per share)					$ 0.81	$ 0.738
Increase in quarterly dividend per common share (percent)					9.80%
Preferred share investment | Preference Shares, Series C
Dividends Payable [Line Items]
Dividend per share (in dollars per share)			$ 0.15975	$ 0.16779	$ 0.25458	0.25305	$ 0.16779	$ 0.25458
Preferred share investment | Preference Shares, Series 11
Dividends Payable [Line Items]
Dividend per share (in dollars per share)					$ 0.24613	$ 0.275
Preferred share investment | Preference Shares, Series 13
Dividends Payable [Line Items]
Dividend per share (in dollars per share)				$ 0.19019				$ 0.275
Preferred share investment | Preference Shares, Series 15
Dividends Payable [Line Items]
Dividend per share (in dollars per share)			$ 0.18644				$ 0.275
Subsequent event | Common shares
Dividends Payable [Line Items]
Common stock, dividends, per share, declared (in dollars per share)	$ 0.81000
Subsequent event | Preferred share investment | Preference Shares, Series A
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.34375
Subsequent event | Preferred share investment | Preference Shares, Series B
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.21340
Subsequent event | Preferred share investment | Preference Shares, Series C
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.15975
Subsequent event | Preferred share investment | Preference Shares, Series D
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.27875
Subsequent event | Preferred share investment | Preference Shares, Series F
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.29306
Subsequent event | Preferred share investment | Preference Shares, Series H
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.27350
Subsequent event | Preferred share investment | Preference Shares, Series J
Dividends Payable [Line Items]
Dividend per share (in dollars per share)		$ 0.30540
Subsequent event | Preferred share investment | Preference Shares, Series L
Dividends Payable [Line Items]
Dividend per share (in dollars per share)		0.30993
Subsequent event | Preferred share investment | Preference Shares, Series N
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.31788
Subsequent event | Preferred share investment | Preference Shares, Series P
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.27369
Subsequent event | Preferred share investment | Preference Shares, Series R
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.25456
Subsequent event | Preferred share investment | Preference Shares, Series 1
Dividends Payable [Line Items]
Dividend per share (in dollars per share)		0.37182
Subsequent event | Preferred share investment | Preference Shares, Series 3
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.23356
Subsequent event | Preferred share investment | Preference Shares, Series 5
Dividends Payable [Line Items]
Dividend per share (in dollars per share)		$ 0.33596
Subsequent event | Preferred share investment | Preference Shares, Series 7
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.27806
Subsequent event | Preferred share investment | Preference Shares, Series 9
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.25606
Subsequent event | Preferred share investment | Preference Shares, Series 11
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.24613
Subsequent event | Preferred share investment | Preference Shares, Series 13
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.19019
Subsequent event | Preferred share investment | Preference Shares, Series 15
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.18644
Subsequent event | Preferred share investment | Preference Shares, Series 17
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	0.32188
Subsequent event | Preferred share investment | Preference Shares, Series 19
Dividends Payable [Line Items]
Dividend per share (in dollars per share)	$ 0.30625