Contract Receivables, Net - Summary of Reconciliation of Billed Contract Receivables Sold to MUF Including Receivables Sold to MUFC And Collected from Customers on Behalf of MUFG And Receivables Not Yet Collected from Customers (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Receivables [Abstract]
Proceeds from sale of billed contract receivables	$ 4.7	$ 17.5