Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Millions	Mar. 31, 2023	Mar. 31, 2022
Statement [Line Items]
Preferred shares, shares authorized (in shares)	10,000,000	10,000,000
Preferred shares, shares issued (in shares)	3,677	3,677
Preferred shares, shares outstanding (in shares)	3,677	3,677
Preferred shares, liquidation preference	$ 3,677	$ 3,677
Common shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, shares authorized (in shares)	75,000,000	75,000,000
Common shares, shares issued (in shares)	52,965,797	52,965,797
Common shares, shares outstanding (in shares)	21,042,652	21,042,652
Treasury shares (in shares)	31,923,145	31,923,145