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 Collected from Customers (Parenthetical) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Receivables [Abstract]
Proceeds from (payments for) sale of billed contract receivables	$ (1.6)	$ 13.4