Consolidated Statements Of Income And Retained Earnings (Parenthetical) (USD $)	9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements Of Income And Retained Earnings [Abstract]
Common stock, cash dividends declared per share	$ 1.45	$ 1.42
Series B, preferred stock dividend rate	6.75%	6.75%