Balance Sheets - MPC (Parenthetical) - shares	Dec. 31, 2021	Dec. 31, 2020
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Mississippi Power
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares outstanding (in shares)	1,000,000	1,000,000